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DL2e Data Logger Hardware Reference

1. Resistance measurements 62 Measuring small changes in resistance 63 Potentiometric measurements 63 Power supplies to sensors and other devices 64 Summary of cards and on board channels 65 Summary of connections for analogue measurements 66 Input and supplementary cards 67 Installing input cards 67 Removing and fitting ribbon cables 68 Analogue Input Card type LAC1 69 15 ch mode 69 30 ch mode 69 Input protection 15 ch and 30 ch modes 70 Analogue Input Card type ACD 1 73 4 Wire Card type LFW1 75 Attenuator Card type LPR1 Input Protection Card type LPR1V 80 AC Excitation Card type ACS1 83 Voltage single ended 86 Voltage differential 89 Voltage up to 50V DC 92 Earth loops and common mode voltages 95 Earth loops 95 Common mode voltages 96 Current 98 Resistance 2 wire 101 Resistance 3 wire 104 Resistance 4 wire 106 Selecting a suitable excitation current 108 Bridge measurements 109 Potentiometer 113 Digital inputs and Counter Card type DLC1 115 Timing accuracy 118 Providing additional digital status channels 120 Relay channels 121 Intermittent logging using relay and event trigger combinations 126 Requirement 126 Explanation 126 Manual control of logging 126 Example Program and Wiring for Intermittent Logging 127 Thermistors 128 Using thermistors with the logger 128 Platinum Resistance Thermometer and other RTDs 131 Using PT100 And other RTDs with the DL2e logger 131
2. These are due to the approximations made by the logger when it performs calculations and stores data These logger errors are discussed in detail below In addition to the logger s contribution errors can be attributed to other sources Sensor errors These depend on the inherent accuracy of a sensor as specified by the manufacturer Sampling errors 1 These can be caused when a sensor is subject to influences that distort measurement of the desired parameter for example poor shielding of an air temperature sensor in bright sunlight These errors can be minimised by careful attention to sensor installation 2 These can be caused when readings of a fluctuating parameter are not logged frequently enough to build up an accurate picture of how it varies Cabling errors Cable resistance can cause significant errors when measuring resistance sensors Techniques for minimising the effects of cable resistance are discussed in 2 3 and 4 wire connection schemes on page 63 Thermistors Errors due to cable resistance on page 129 and Platinum Resistance Thermometers Errors due to cable resistance on page 132 Adding errors from different sources The logger specification in Appendix A quotes maximum and typical accuracy figures for the logger The accuracy calculations in this section and the figures quoted in the temperature measurement section are derived by adding together maximum error figures This procedur
3. CT LOTELO LYU LRA UNDERSIDE 19730 suitch Q 0O set to 15 Terminal mounted divider resistors Figure 20 Sensor connections voltage up to 50V Page 94 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Earth loops and common mode voltages Earth loops and common mode voltages Earth loops supply DL2e Hardware Reference Computer with non isolated mains power or printer An earth loop is literally two or more earth conductors connected in a loop configuration caused when there is more than one connection route between a sensor and the logger s earth You will create an earth loop if you make a single ended connection to a sensor whose OV output is already electrically connected to the logger s earth Figure 21 illustrates some possible earth loop connection routes to look out for Current flowing round an earth loop causes a voltage drop in the cable connecting the sensor to the logger s negative input terminal producing an error in the voltage reading Sensor Alternative sensor power supplies Safety earth terminal Altenative logger power supplies Shared Sensor Power Supply Power or Battery Supply non isolated Mains earth Figure 21 Potential interconnections between sensor output V and logger earth Do not use single ended connections if any of these routes are present in your system Earth l
4. Page 62 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Overview of electrical measurement techniques You choose an excitation current from 2 20 200 or 2000u A The logger performs the conversion from mV to Q or kQ for you 2 3 and 4 wire connection schemes LAC1 ACD1 and LFW1 cards can be used for general purpose resistance measurements 2 wire 3 wire and 4 wire connection schemes are available They differ in accuracy but don t affect the logging program 2 wire connection schemes are most straightforward and are available on both LAC1 and LFW1 cards The measured resistance includes the resistance of the connecting leads so 2 wire connections are suitable for measuring relatively large resistance s where the resistance of connecting cables is negligible The LAC1 in 30 ch mode introduces an additional error of up to 20Q and is not recommended for accurate measurement of resistance s smaller than around 10 kQ For improved accuracy consider the following options e Minimise cable resistance errors keep cable lengths as short as possible and use heavy duty low resistance cable e Compensate for cable resistance by configuring individual channels with an offset for linear conversion to engineering units only and not for non linear sensors see Conversion factor and offset in the on line Help e Use 3 wire connection to a LAC1 or ACD1 where only one connecting lead the return lead
5. The Input Channel tab of the Channel Properties dialog for the channel group will then offer suitable sensor types in the Sensor Type list or if you select lt Custom sensor type gt the Measurement tab will offer suitable options in the Electrical Measurement list Programming an Event Trigger Channel The Channel Properties dialog for on board digital channels 61 62 contains a Digital Channel tab which allows you to program these channels as ordinary input channels or to program them as start or data triggers Select the function that you require then provide further details in the other tabs of the Channel Properties dialog Programming a Sensor Type In the Measurement tab of the Sensor Type Properties dialog select one of the following Electrical Measurement options e Counter e Frequency You can also select the following measurement type for use with on board digital channels only e Logic Level DL2e Hardware Reference Page 117 Sensors and Input Cards Hardware Reference Digital inputs and Counter Card type DLC1 Timing accuracy Counter and frequency channels The logger reads the number of counts that have accumulated over a sampling interval and in the case of frequency channels divides by the nominal length of the sampling interval Actual intervals between sampling of counter and frequency channels are not entirely repeatable Over runs Over runs cause late sampling and will affect not only the reading fl
6. Hardware Reference Relay channels Warmed up sensor connections A common mistake is to connect a warmed up sensor to the common or NC warm up relay terminal to get a sensible result when first setting up and READing the sensor For correct warm up operation you must use the NO terminal and READ the sensor as described above 2 wire 4 20mA current loop transducers The illustration below shows the wiring for switching the logger s internal power supply to a 2 wire 4 20mA transducer Note that the power supply return must be kept away from the logger s analogue earth Use a differential connection for measuring the voltage across the shunt resistor or mount the shunt resistor R1 on an LPR1 or LPR1V card See also Current measurement on page 98 eaka Figure 36 Sensor connections power supply for 4 20 mA transducers Page 125 DL2e Hardware Reference Sensors and Input Cards Hardware Reference Intermittent logging using relay and event trigger combinations Intermittent logging using relay and event trigger combinations Page 126 The example below shows how the logger s relay and event trigger functions can be combined so that data is logged only when a condition on an input channel is true Requirement Channel is to monitor a temperature When this temperature rises above 20 C temperature readings are to be logged from channels 1 to 5 at 5s intervals No readings are to be logged when the te
7. Potentiometer Bridge e Resistance 2 wire 3 wire 4 wire no offset e Thermocouple Single ended Differential low CM Differential high CM Factory set offset e DC Voltage Single ended Differential low CM Potentiometer e Resistance 4 wire 20C PT100 offset e Thermocouple Single ended Differential low CM Alternative offset e DC Voltage Single ended Differential low CM Potentiometer e Resistance 4 wire 20C custom offset e Thermocouple Single ended Differential low CM Page 79 Sensors and Input Cards Hardware Reference Attenuator Card type LPR1 Input Protection Card type LPR1V Attenuator Card type LPR1 Input Protection Card type LPR1V Capabilities Channels LPR1 and LPRIV are supplementary cards for fitting in the logger in series with an analogue input card Each serves two terminal groups but provides no additional channels Voltages up to 50V and currents Both LPR1 and LPR1V have sockets for mounting precision resistors When fitted in series with a LAC card resistors can be fitted in a voltage divider configuration to attenuate voltages up to 50V to a value that the logger can measure or as shunts for converting currents to voltages Input protection LPR1V has transient absorbing varistors fitted on all inputs It can be fitted in series with LAC1 and LFW1 cards to provi
8. Sensors and Input Cards Hardware Reference Overview of electrical measurement techniques In single ended connection schemes the logger s negative input terminal is connected to the logger s earth In differential connection schemes neither of the logger s input terminals is connected directly to the logger s earth and the difference in voltage between the and input terminals is measured The choice between single ended and differential connection determines the logger s ability to measure a signal accurately and doesn t affect the logging program As a general rule good results can be obtained using single ended connections with either analogue card The exceptions are e low level signals such as thermocouples measuring ambient temperatures LAC1 in 30 ch mode is not recommended 15 ch mode is better see Voltage single ended on page 86 e electrically noisy environments differential connection with bias resistors or sensor earthing is recommended for best rejection of induced electrical noise particularly with sensors that have a low level output connected to the logger with long lengths of unscreened cable in noisy electrical environments Fully floating connection is not recommended e existing alternative earth paths to avoid problems associated with earth loops sensors should be earthed via a single route only A single ended connection provides an earth path and should be avoided in situations whe
9. The ACD1 is intended mainly for measuring sensors that have an ac output signal or that are excited by the ac source card type ACS1 Capability Channels 15 channels are provided on one terminal group Voltage inputs Differential A wire link can be fitted on the screw terminal block for single ended measurements Inputs signals up to 2V dc or 2Vac true rms can be measured Resistance measurements 3 wire current excited A wire link can be fitted on the screw terminal block for 2 wire measurements see Figure 8 ACD 1 circuit board layout Setting up Ribbon cables Connect one ribbon cable from the card to any terminal group All sensor connections are as LAC1 in 15 channel mode differential Ribbon cable frorn any termina group Figure 8 ACD1 circuit board layout Programming Issues Programming an Input Channel Select Input Card Type ACD for the channel group that is connected to the ACD1 card The Input Channel tab of the Channel Properties dialog for this channel group will then offer suitable sensor types in the Sensor Type list or if you select lt Custom sensor DL2e Hardware Reference Page 73 Sensors and Input Cards Hardware Reference Analogue Input Card type ACD1 type gt the Measurement tab will offer suitable options in the Electrical Measurement list Programming a Sensor Type In the Measurement tab of the Sensor Type Properties dialog select one of the following Electrical Measu
10. number of data L all readings Ensure your printer is connected and online Press PRINT to confirm that the above choices are correct and to start printing lt PRINT gt confirms other keys abort The message printing indicates that the logger is busy outputting data When finished the logger either offers auto printing see below or returns to the Keypad main menu Auto printing Auto printing allows you to print out data of a specified type automatically as it is logged to memory First start logging The logger only offers the auto print option if it is already logging Select the PRINT function select the data type TIMED TRIG 61 TRIG 62 that you want to auto print select all readings and confirm When the logger has finished printing all the data up to the present time it offers the option to auto print AUTO PRINT yes Disabling autosleep Some printers and data collection devices may spuriously interpret powering up of the logger s serial port as a character for example when the logger wakes to log data To prevent this happening you can disable autosleep by selecting no in the AUTOSLEEP menu but note that this will result in greatly increased power consumption AUTOSLEEP no The logger now returns to the Keypad main menu Auto printing does not interfere with the logger s keypad functions and you can use the PC to communicate with the logger in the normal manner The logger suspends
11. 10 30 min or 1 2 4 12 or 24 hours programmable for each channel Readings can also be reduced to averages maxima or minima at these intervals Typically 10 channels sec Input channels 60 Channels maximum depending on the number and type of input cards installed plus 2 resident digital inputs and 2 relay outputs Analogue inputs Analogue Card LAC1 Each LAC multiplexer card can select analogue inputs from Either 15 channels of differential voltages and 3 wire resistances Or 30 channels of single ended voltages and 2 wire resistances It directly measures voltages up to 2V or resistances lt IMQ Voltages up to 50V and currents can be measured using attenuator resistors mounted on the input screw terminals or on an LPR1 or LPR1V card Analogue Card ACD1 Each ACD1 card can select analogue inputs from 15 channels of differential voltages and 3 wire resistances It directly measures voltages up to 2Vdc 2Vac rms or resistances lt IMQ 4 Wire Card LFW1 Each LFW1 card can select up to 12 bridge potentiometric differential voltage or 2 or 4 wire resistance sensors 4 wire resistance measurements virtually eliminate cable resistance errors PT 100 platinum resistance thermometers e g DIN 43760 BS 1904 type are measured over 200 C to 850 C In the 17 C to 57 C range of logger and PT100 temperature 0 01 C resolution and 0 2 C accuracy is obtained Page 138 DL2e Hardware Reference Appendices
12. 62 type Data bits Data collection devices Data collection terminal Data file size of Data trigger Date format DEFAULT configuration Deleting malfunction reports Desiccant regeneration Diagnosing communication faults Differential voltage Differential voltage measurement Digital input signals status Digital status DIP switch Disk drive Display contrast DL2 Control Panel Logger Sensors panel DLC1 counter card DOWN function d trigger Earth loops Earth loop Echo test Electrical 20 20 15 59 49 60 115 148 115 22 117 108 62 80 98 9 30 30 37 10 31 36 31 34 10 30 30 30 34 38 33 50 36 36 32 60 18 20 48 15 26 55 56 53 69 73 75 61 89 115 60 60 115 120 48 50 36 49 19 22 19 22 115 33 23 62 95 53 Page 157 induced noise noisy environment Electrical mains frequency Electro Magnetic Compatibility Ending auto print Erase data up to Erasing data Error cable resistance DL2 Control Panel PT100 thermistor measurement Event EVENT Event trigger channel ed data ed start logging testing Excitation current voltage External power supply F Fenwal Unicurve Fenwal Unicurve thermistors Field installation File format Flags Follow on data Format data file Frequency resolution Frequency input Full bridge Fully floating sensor connection Function DOWN keypad PRINT READ s 14 SET TIME START t 14 WAKE Fuse r
13. auto printing while the serial port is busy with another function for example communicating The backlog of data is output on the next occasion when the logger would normally auto print i e when data of the given type is next due to be logged Note To disable autosleep fit a shorting link on the main board in position H2 See Figure 2 Main circuit board layout To stop auto printing At the Keypad main menu press PRINT If the logger has been auto printing it stops auto printing and exits the PRINT function ending auto print DL2e Hardware Reference Page 35 Collecting and Erasing Logged Data Hardware Reference Using other data collection devices Using other data collection devices Page 36 It is possible to use any data storage device with a suitable RS232 serial port for collecting data from the logger The process is identical to outputting data to a printer except that you can choose the BIN format option You can then transfer the data to your PC for processing as required This technique may be of interest if you need to collect data from a logger situated at a remote site without interrupting logging However if you have to purchase a piece of equipment specifically for this purpose we strongly recommend that you consider a portable PC instead it will be considerably more flexible and probably not much more expensive than a portable floppy disk drive or dedicated data collection terminal Suitable devices
14. presentation is cluttered with quotes and commas PRN Printable ASCII format with data in engineering units space separated and aligned in columns The PRN format is suitable for printing directly The contents and arrangement of data is similar to DAT files with the following major differences e Items are separated by spaces instead of commas and aligned in columns e Text items are not enclosed in double quotes e Error flags are appended to readings instead of preceding the reading that they refer to Data starting The logger keeps a record of where to find the first item of data in its memory and if it has been outputting data a record of where to find the next data to be output The logger can thus allow you to specify whether you want to collect data which follows on from the last data that you have collected follow on data or to duplicate the data that you have already collected i e data starting from the first item in the logger s memory You will only be offered this choice if you have already collected data from the logger on one or more occasions and not erased it from the logger s memory You cannot of course collect data that you have erased from the logger s memory Differences between timed and event triggered data When collecting timed data you will be prompted with the date and time of the first line of data that will be output When collecting event triggered data you will be prompte
15. t have any current driving capacity and can be eliminated without detrimental effect by earthing either the sensor or one of the logger s input terminals You can t measure these common mode voltages with a normal voltmeter because the effect is like earthing the signal Nevertheless induced common mode voltages can easily push the inputs outside the logger s common mode range and make the signal unreadable This is why single ended connections or other earthing schemes are essential for sensors that are otherwise electrically isolated from the logger Voltage sources between the logger s earth and the sensor e g where an earth loop occurs Such voltage sources are low impedance You can measure them with a voltmeter and if they exceed the logger s common mode range the common earth connections must be broken by using isolated power supplies or optically isolated data links Earthing the inputs doesn t work Page 97 Sensors and Input Cards Hardware Reference Current Current The connection schemes on this page are suitable for measuring DC current Examples of sensors with a current output are photodiodes and 4 20mA loop transducers A shunt resistor mounted either on the screw terminals or on an LPR1 or LPR1V card in series with a LAC1 card is required for this purpose Setting up Mounting shunt resistors on screw terminals e Setup the LAC1 or LFW and fit ribbon cables for single ended or differential voltage
16. Appendix A DL2e Technical Specifications Voltage source 1 0486V to approx 4V adjustable 60mA max per group of 6 channels Output impedance lt 0 50 Temperature coefficient lt 50ppm C 1 0486V repeatability lt 0 5mV DC Voltage readings via LAC1 ACD1 or LFW1 12 bit sign 4 Ranges user selected or autoranged Errors Maximum values shown with typical figures in brackets Logger Temperature 20 C to 60 C Full scale error 0 07 0 04 0 02 0 1 Long term stability 0 25 0 02 over 1 year Differential Offset 10 LV 3uV 0 02 12 LV 0 02 Noise 0 2uV RMS Input Impedance approximately 100 MQ Common Mode Range 2V or 1 05V if input closer to logger OV than input Common Mode Rejection ratio 140 dB typical on voltage range 1 AC Voltage readings via ACD1 12 bit sign 4 Ranges user selected or autoranged Input type and frequency Input Level mV ac rms Sinusoidal signals 0 to 10 Zero reading in this range 45 to 60 Hz 10 to 50 3mV 20 to 60 C 50 to 100 0 6 of reading 0 25mV 100 to 2000 0 6 of reading Sinusoidal signals 10 to 2000 Maximum additional error 65 to 1000 Hz 0 5 of reading Non sinusoidal signals 10 to 2000 Maximum additional error Crest factor 1 0 to 1 7 1 0 of reading square or triangular wave Common mode rejection at de 0 1 65dB up to 1kHz 0 5 45db DL2e Hardware Reference Page 139 Appendix A DL2e Technical Specifi
17. C if recalibrating the factory set PT 100 offset and the OFFSET trimmer so that the voltmeter gives a reading close to zero e The 20C and OFFSET trimmer settings interact and you may have to repeat the adjustment a few times until the results stabilise Voltage sources There are two voltage sources on an LFW1 one for each group A and B of 6 channels Each source is automatically turned on whenever one of the 6 channels in that group is measured Voltage source adjustment trimmers A and B Adjust the voltage source outputs for their respective channel groups from 1 0486 Volts up to about 4 Volts Current limiting The 6 channels in a group can draw a total of 6 0mA from the voltage source Higher currents are automatically limited to prevent damage from accidental short circuits etc The current limiting LED light emitting diode indicator on the card lights whenever the voltage source is overloaded and unable to supply enough current at the required voltage For example 1 048V is suitable for exciting a full group of six 120Q strain gauges since the current drain would be Vxn__ 1 048V x6 R 120Q 52 4mA Page 78 DL2e Hardware Reference Hardware Reference Sensors and Input Cards 4 Wire Card type LFW1 If the voltage is increased and the total required current rises to 60mA current limiting takes place and the current limiting LED indicator lights The voltage source is then not stabilised and might cause misle
18. Collecting and Erasing Logged Data Data collection options The HFD format is a hexadecimal format containing compressed data 4 bytes per reading retrieved from the logger using a hexadecimal protocol which permits frequent checks during transmission but is substantially slower than the binary protocol Both these file formats can be imported directly into Microsoft Excel using Dataset Import Wizard or you can open them for viewing in Dataset Viewer DL2 Control Panel does this for you automatically after retrieving a dataset Neither of these file formats are suitable for printing or importing into other data processing programs directly They need to be converted to DAT format open the file in Dataset Viewer and select the Save As command File menu Their structure is described in the DL2e Programmers Guide DAT Comma separated ASCII format with text enclosed in double quotes and data values separated by commas The Save As command File menu in Dataset Viewer creates DAT files from BIN or HFD files The detailed file structure is described in the Reference Topics section of Dataset Viewer s on line Help DAT files can be input directly into many data processing software packages and are easily read by programmes written in common computing languages They can also be imported into Microsoft Excel using Dataset Import Wizard DAT files can be viewed and printed out directly for example using Notepad but the
19. Hardware Reference AC Excitation Card type ACS1 SENSOR TERMINA AG SOURCE RIB3O0N AC INPUT CARD ACI To GO r CABLE 1al 114 WET 2RY lya KAT IAI Oars WATERNARK Z3 Mwzy e soncecce 1 ot 4 1a channpla card a ANA OG B cUNE REMOVE LUMPER 10 RES S7CR cearnas ured br nhar mani rl Kaw Figure 14 ACS1 system diagram A Je Power Connector Figure 15 ACS1 circuit board layout Page 84 DL2e Hardware Reference Hardware Reference DL2e Hardware Reference Sensors and Input Cards AC Excitation Card type ACS1 itla satui Granie see pari at eluatny live 34 way Ribbon aablo sonras we Znane TDA oa Os oantteton Figure 16 ACS1 circuit board channel details CONNECTING ACS POWER SUPPLY LEAD Power sLpuly jumacrs R buan cable to msir board Ca 67 prk lead CH 63 NO red ced Viewed from inside the DL2e s case Relays VaR OS Figure 17 ACS1 power connections Page 85 Sensors and Input Cards Hardware Reference Voltage single ended Voltage single ended Single ended sensor connection is suitable for measuring DC voltages up to 2V The source impedance of the voltage source should be less than 24kQ for full logger accuracy LAC in 30 ch mode is not recommended for accurate measurement of low level signals less than 32mV It can introduce a relatively large offset error typically in the region of 20uV in addition to the logger s normal d
20. LAC1 Voltage inputs Single ended only with unspecified voltage offset depending on the sensors connected to the card typically 20uV Resistance measurements 2 wire only with additional offset error up to 20Q typically 6Q Setting up 15 30 switch Set to 30 position Ribbon cables Connect one or two ribbon cables from one or two terminal groups on the terminal panel e terminal groups 1 15 31 45 connected only to the terminal block labelled 1 15 31 45 e terminal groups 16 30 46 60 connected only to the terminal block labelled 16 30 46 60 Programming Issues Programming an Input Channel Select Input Card Type LAC1 30 channel for the channel group that is connected to the LACI card The Input Channel tab of the Channel Properties dialog for this channel group will then offer suitable sensor types in the Sensor Type list or if you select lt Custom sensor type gt the Measurement tab will offer suitable options in the Electrical Measurement list Programming a Sensor Type In the Measurement tab of the Sensor Type Properties dialog select one of the following Electrical Measurement Connection Requirements combinations e DC Voltage Single ended e Resistance 2 wire Thermocouple Single ended Input protection 15 ch and 30 ch modes Input channels on the LAC1 are protected against a continuous overload voltage up to 15 V They can also survive brief spikes at muc
21. Page 38 I PRINT or ERASE ERASE If the logger has been programmed with a password you will be prompted to enter it See page 17 for details of how to enter a password I password Select TIMED TRIG 61 or TRIG 62 data type Press PRINT to accept the option shown DATA TYPE TIMED The logger briefly displays the date and time up to which data will be erased For timed data this is the date and time of the first item of data which will not be erased erase data up to 12 02 11 15 30 For Event triggered data this is the current date and time to indicate that all data of the selected type TRIG 61 or TRIG 62 up to the present time will be erased Press PRINT to proceed with the erasing data lt PRINT gt confirms other keys abort DL2e Hardware Reference Hardware Reference DL2e Logger Hardware Erasing data from the logger s memory Chapter 5 DL2e Logger Hardware DL2e Hardware Reference This section contains information on various hardware related topics that concern general operation of the logger rather than its data collection and measurement functions Sub sections within this chapter deal with e Power supplies e Rechargeable battery packs e Installing IC s e Communication parameters e Making communication cables e Modems e Testing communication e Electrical mains environment e Display viewing angle e Field installation e Security e Maintenance storage
22. Resolution is 8uV on voltage range 2 e Differential offset is 10uV e Maximum error is 8nV 1OuUV 18uV Note that e The differential offset is only specified for differential voltage readings Single ended voltage readings may have much larger offsets typically 20uV e There is a 10 hysteresis band between voltage ranges to prevent the logger changing voltage ranges too frequently this means that voltages in the upper 10 of each voltage range may be read with a resolution corresponding the next highest range Page 145 Appendix B Accuracy of logger readings Appendices Other voltage reading error sources are Long term 0 25 max 0 02 typical asmall typical error stabilit over year Noise 0 2uV RMS negligible Input Impedance approx 100 MQ negligible for source input impedance lt 10kQ Common Mode 2V or 1 05V if logger s the average of the input Range input is nearer to logger s voltages must be within the earth than the input Common Mode Range Resistance reading accuracy The following additional errors apply to resistance readings Logger 20 C 20 to 60 C Temperature 20 3 full scale 0 6 to 50 C 20 05 10 1 2 Wire LACI only 20Q 6Q typical To calculate the error in a resistance reading e First calculate the voltage the logger sees when the chosen excitation current is applied to the resistor V kxe XR determine the voltage error as above and conver
23. Rt Resistor position R4 R PRT switches DL2e Hardware Reference S O m gt co Sensors and Input Cards 4 Wire Card type LFW1 fit stable resistors in positions R1 and R4 Select R4 to be slightly greater than Rpase the new resistance offset and calculate R1 using the formula ee XxX Vinmax lt 2 097V Ri k2 Connect a calibration resistance of the exact value Rpase to one of the LFW1 channels using the 4 wire connection scheme and program the logger to read this test channel In setting up Sensor Characteristics remember that the logger will measure Rbase less than the actual resistance enter Rpase as an offset or subtract Rpase from actual resistance values when entering a linearisation table Channel group B Channel group A ribbon cable from ribbon cable from any terminal group any terminal group Figure 9 LFW1 4 wire analogue input card Page 77 Sensors and Input Cards Hardware Reference 4 Wire Card type LFW1 VU offset x typical values XX Uoffset only applied to resistance measurements Figure 10 LFW1 input stage schematic diagram Adjustments With a calibration resistor connected to a suitably programmed test channel proceed as follows e Connect a voltmeter across the pair of pins labelled AMP on the logger s main board e Set the R PRT switch to the R position and READ the test channel e Adjust the 20C trimmer until the reading corresponds exactly to Rpase 20
24. Thermocouples 133 Appendices 136 Appendix A DL2e Technical Specifications 138 Logging 138 Logging interval and speed 138 Input channels 138 Analogue inputs 138 Analogue Card LAC1 138 Analogue Card ACD1 138 4 Wire Card LFW1 138 Attenuator Card LPR1 140 Input Protection Card LPR1V 140 Digital inputs and outputs 141 Digital inputs 141 Relay outputs 141 Counter Card DLC1 141 DL2e Hardware Reference Page v Other specifications Contents Rechargeable battery pack LBK1 Electro Magnetic Compatibility Appendix B Accuracy of logger readings Adding errors from different sources Analogue accuracy Voltage reading accuracy 146 Resistance reading accuracy Calculation of logger analogue accuracy a worked example 147 Arithmetic accuracy 148 Analogue sensors linear conversion to engineering units 148 Counter and frequency sensors linear conversion to engineering units Linearisation errors 148 149 Appendix C Calculating the speed of data readings Appendix D Resident linearisation tables Thermistor tables 150 152 153 Thermocouple tables 154 Appendix E Identifying components on cards Index 155 156 Page vi DL2e Hardware Reference Hardware Reference About this manual Hardware Reference About this manual This manual contains information about e using the keypad on the front panel e power supplies and the recha
25. a 1 4 bridge This technique is particularly suited to the PT100 platinum resistance sensor where a base resistance can be specified to a high degree of accuracy and several PT100 s can be referenced to the same base resistor It can also be set up for other sensor types Potentiometric measurements The voltage excitation facility on the LFW1 can be used for potentiometer measurements avoiding the need to measure an absolute resistance see Potentiometer on page 113 DL2e Hardware Reference Page 63 Sensors and Input Cards Hardware Reference Overview of electrical measurement techniques Page 64 Power supplies to sensors and other devices Many sensors require a power supply including most that have a voltage analogue or digital or current output Notable exceptions are thermocouples voltage and photodiodes current Don t confuse power supplies with excitation voltages used for resistance and bridge sensors Excitation is precise sensor output is proportional to excitation level Power supply is not within limits the supply voltage does not affect sensor output Relay channels 63 and 64 can be used to draw power from the logger s own battery or power supply or to control external power supplies Sensors can be permanently connected to the logger s battery by fitting the power supply jumpers see Figure 33 sensor connections relays Alternatively in situations where economical power consumption
26. a sensor manually which during normal logger operation would need to be powered using the warm up relay WRM function On exiting the READ function or when the logger autosleeps the relays are returned to their normal state i e the state they would be in if they had not been switched by the READ function Note that logging requirements take priority over manual operation of the relays If the logger wakes to LOG or WARM UP it will override any manual settings of a relay In particular the logger will not allow a warm up relay to be switched off manually during a warm up period preceding a reading Testing event trigger channels An event trigger channel in the CLR state does not normally detect events When reporting its status the logger activates the trigger in a test mode Events are then detected and an EVENT message displayed but the normal trigger function remains disabled When finished Press READ to return to the Keypad main menu Error status During logging the logger detects and acts on four categories of malfunction e Battery failure e Memory full e Sensor malfunctions e Over run errors The action taken by the logger on encountering each of these malfunctions and associated malfunction reports is described in Sensor malfunctions below The logger s WAKE function and the Errors panel in the PC s DL2 Control Panel reports battery memory and sensor malfunctions but not over runs Battery failure
27. and other RTDs Use sensor code PT4 of type Platinum Resistance Thermometer type Pt100 simple resistance supplied in the sensor library This suits PT100 sensors with a temperature coefficient of 0 385Q per C Other RTD using LFW1 with offset Create a new sensor type When entering a linearisation table remember to subtract the offset from the resistance values that you enter in the table Accuracy Logger contribution to PT100 errors The table below shows the maximum logger contribution to PT 100 temperature measurements without and with resistance offset Logger Temperature 20 C to 60 C 200 C to 80 C 0 37 C 0 78 C 80 C to 600 C 2 0 C 17 C to 57 C 0 06 C _ 0 20 C LFW1 with 107 79 Q o4 0 43 C 1 08 C PRT Temp range LAC1 15 ch or LFW1 without offset resistance offset 317 C to 836 C 3 34 C 8 06 C See Appendix B for a worked example of a logger accuracy calculation Errors due to cable resistance For 2 or 3 wire connection cable resistance has a big effect on the accuracy of PT100 readings 2 6 C error per Q For 4 wire connection to LFW1 the error is less than 0 001 C error per Q Page 132 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Thermocouples Thermocouples Thermocouples are sensors that generate a voltage output They comprise a junction of two dissimilar metals e g copper constantan The thermoco
28. cards when an ACS1 is fitted These channels are then not affected by the ACS1 Installation The ACS1 card mounts on the inside of the DL2e terminal panel attached by 4 x 34 way through connectors To install apply even pressure across the card gradually easing the 4 connectors together The normal 34 way ribbon cables connect between the ACS 1 and the input card NOTE polarisation marking on ACS1 card The ACS1 is powered from the DL2e power 7 15 Vdc via a warm up relay with jumper fitted This is connected via flying leads with header soldered to the CH63 NO amp CH62 OV pins on the inner side of the terminal card If the ACS1 has not been factory fitted then you will need to connect the power supply lead See Figure 17 ACS1 power connections for details Setting up Interpreting readings The 2000 mV AC from the ACS1 is divided by the 10 KQ resistor on the ACS1 card in series with the sensor resistance The resulting Vac reading can be interpreted afterwards as a sensor resistance e AC mV reading where R is the sensor resistance in kQ Therefore R A00 LUN if V 400mV then R DUXON 2 5kQ 2000 V 1600 If measuring soil moisture the sensor calibration will relate sensor resistance to soil matrix potential Setting a channel of the logger to read soil temperature will also be useful as the readings can then be compensated for temperature variations DL2e Hardware Reference Page 83 Sensors and Input Cards
29. channel 1 is not programmed ch reading units 1 TM1 cold jn After a pause the sensor code and label are replaced with a reading in engineering units or by an error message if the sensor is faulty or incorrectly connected ch reading units 1_ 20 95 deg C Error messages may be o s limits outside limits over range or noisy These conditions are discussed in detail on page Sensor malfunctions on page 25 l ch reading units 1_ o s limits The display is up dated regularly until e you press Oor Tto move on to another channel e you press READ to exit the READ function and return to the Keypad main menu e the logger autosleeps To change channels DL2e Hardware Reference Press Oor T The reading on the next or previous programmed channel in numerical order will be displayed 1 20 95 deg C 2_ 999 9 ohm Note Even if two channels are displayed only the channel marked by the underline cursor is updated i e channel 2 in this example Page 23 Interrogating the DL2e logger Hardware Reference Error status Fast scrolling Hold down o or T for fast scrolling through the channels Exercising relay channels When you move onto a relay channel the logger initially displays its status and then switches the relay between ON and OFF states at 2s intervals When oor Tare pressed to move onto another channel the relay remains switched in the state last displayed You can use this feature to power up
30. differential Differential sensor connection is suitable for measuring DC voltages up to 2V Source impedance of the voltage source should be less than 24kQ for full logger accuracy Fully floating Fully floating connection is suitable for sensors with an existing connection to the logger s earth or with a low impedance common mode voltage less than 2V Bias resistors earthed sensor Differential connections with the sensor earthed or with bias resistors fitted are superior alternatives to single ended connection These schemes are recommended for inputs susceptible to picking up high impedance common mode noise for example thermocouples on long leads in electrically noisy environments Setting up LAC1 15 ch mode e Set 15 30 switch to 15 e Connect one ribbon cable only from any terminal group to the position marked differential on the card ACD1 e Connect a ribbon cable from any terminal group to the card LFW1 e Set the R PRT switch to R position for optimum common mode rejection see 4 Wire Card type LFW1 on page 75 e Connect one or two ribbon cable s from any terminal group to either or both positions on the card LAC1 ACD1 and LFW1 e Fit bias resistors or earth the sensor if appropriate 100kQ is generally a suitable value for bias resistors Programming Issues When programming a sensor type or entering measurement details for a lt Custom sensor type gt proceed as fol
31. if no user input occurs i e a key press or communication signal at any other time Autosleeping can be disabled when using the auto print feature See Auto printing on page 35 Logging After starting logging the logger normally autosleeps and then wakes when required to take readings from sensors or to switch warm up relays The logger is said to be logging even though it is not actually recording data at a given instant for example in messages such as logging started or already logging LOG EVENT WARM UP While logging recording of data may be initiated either by the logger s internal clock readings taken at regular intervals known as timed data or by a signal on a channel programmed as a data trigger or event triggered data Switching of a warm up relay is controlled by the logger s clock These tasks take priority over keypad functions and communication When carrying out one of these priority tasks the logger flashes up a message on its display to indicate that other logger functions are temporarily suspended The respective messages are e For recording timed data LOG e For recording event triggered data ever tid _ e For switching a warm up relay Page 10 DL2e Hardware Reference Hardware Reference About the DL2e Logger Logging a The logger is said to be performing a LOG EVENT or WARM UP While communicating with the logger you may n
32. illustrated in Figure 2 Main circuit board layout The IC s must be inserted as illustrated with the notch on the left when looking at the main board with the printed text upright Fitting memory expansion Memory expansion IC type LME6 is fitted in RAM 1 position see Figure 2 Main circuit board layout Fitting this device will double the reading capacity available to the DL2e Inserting IC s To insert an IC make sure all the pins are straight and they line up correctly with the holes on the socket If they do not line up use a ruler or other flat object to bend them slightly Push the IC into the socket making sure that none of the pins get bent underneath When finished After installing or removing IC s replace the batteries and lithium cell and coldboot the logger The logger will automatically coldboot when next woken if the batteries and lithium cell have been removed as instructed above DL2e Hardware Reference Page 49 DL2e Logger Hardware Hardware Reference Communication parameters Communication parameters The logger communicates with other devices such as computers and serial printers through the RS232 serial port on the side panel of the logger s case on older loggers the RS232 connector is on the front panel Communication parameters determine the speed and format of serial data communication For the logger to communicate successfully with a computer printer or other device their communic
33. in e The conversion factor for configuring the logger is then Programming Issues When programming a sensor type or entering measurement details for a lt Custom sensor type gt proceed as follows in the Measurement tab of the Sensor Type or Channel Properties dialog e Select Electrical Measurement DC Voltage e If programming a sensor type also select Connection Requirement as described in Voltage single ended or Voltage differential sections e Enter suitable conversion factor and offset or linearisation table for converting the input signal seen by the logger ie the voltage across the shunt resistor in mV which equals the current in mA scaled by R to engineering units Page 98 DL2e Hardware Reference Hardware Reference Accuracy Sensors and Input Cards Current The logger s voltage measurement accuracy figures see Appendices A and B apply to current measurements with the following additional error contributions from the shunt resistor See also DL2e Hardware Reference If using a calculated value for the conversion factor add the tolerance of the resistor The temperature coefficient tempco of the shunt resistor has to be added if the logger is to operate over an extended temperature range For example if using a 15ppm C resistor and operating over 20 to 60 C the maximum tempco error contribution is 40 C x 15ppm 600ppm 0 06 about a 20 C base 2 wire 4 20mA curren
34. is required use the logger s warm up function to power up sensors for just long enough to take a reading See also Comments on earth loops and common mode on page 95 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Overview of electrical measurement techniques Summary of cards and on board channels Card Channels Capability Terminal Groups LAC1 30 ch mode 15 or 30 channels VOLTAGE single ended 1 or 2 terminal groups z RESISTANCE 2 wire 200 error 15 channels per terminal LAC1 15 ch mode 15 channels VOLTAGE single ended differential 1 terminal group RESISTANCE 2 wire 3 wire LFW1 6 or 12 channels VOLTAGE single ended differential 1 or 2 terminal groups RESISTANCE 2 wire 4 wire 6 channels per terminal group BRIDGE full half 3 wire quarter current or voltage excited POTENTIOMETER LPR1 1 or 2 terminal groups Resistor mounting positions fitted in series with LAC1 SHUNT for current measurement provides no additional DIVIDER for voltage measurement up to channels 50V LPRIV 1 or 2 terminal groups fittedin Additional input protection series with LAC1 or LFW1 Also if fitted to LAC1 provides no additional provides resistor mounting positions as channels LPRI DLC1 15 channels COUNTER FREQUENCY ACD1 ACS1 15 channels VOLTAGE AC voltage true rms 2V ac rms 1 terminal group crest factor 1 0 to 1 7 DC voltage 2V dc RESISTANCE 2 wire 3 wire ACS1 1 4 termina
35. is specified to work from 20 C to 60 C Battery life is reduced at temperature extremes The logger s display works at 20 C but may become slow and difficult to read at low temperature Exposure to sunlight Moisture The case will slowly degrade if left in bright sunlight over long periods For this reason and to prevent over heating the logger should be installed in a shaded location When reading thermocouples For best accuracy minimise heat flow down the thermocouple wires to the terminal panel e Use thin sensor cables e Minimise temperature differences by coiling some of the sensor cable next to the logger in the shade The logger has two compartments the main case and the terminal compartment which need to be separately protected from moisture Main case The main case is waterproof but not hermetically sealed It breathes as the temperature changes and moist air gets drawn into the case To achieve high quality analogue performance the inside of the logger s case must be kept dry High levels of humidity can cause inaccurate readings even in the absence of condensation A bag of desiccant should be fitted inside the main case held by the two clips opposite the RS232 connector and replaced regularly The humidity indicator on the front panel is blue when dry The desiccant bag should be replaced as soon as the indicator starts to turn pink Terminal compartment DL2e Hardware Reference
36. life remaining O E Effective battery life is reduced at extremes of the logger s operating temperature range 20 C to 60 C Low battery The logger checks the battery or power supply voltage each time it wakes and if the voltage is less than 7 0 V it e briefly displays the message battery failure on its display e if logging stops logging and compiles a malfunction report e returns to sleep DL2e Hardware Reference Page 41 DL2e Logger Hardware Power supplies Hardware Reference e DL2 Control Panel will fail displaying an error message Change the battery to resume normal operation Remarks It is common for batteries to recover slightly after a period of rest It is possible to wake the logger after it has stopped logging due to battery failure and to find a battery report a little above 7 0 V The check for low battery voltage occurs only when the logger wakes from sleeping A logger kept awake for extended periods for example with autosleep disabled while auto printing can run down its batteries well below the critical battery voltage with unpredictable results If you want to operate the logger in this way it is preferable to connect an external mains power supply adapter If the logger s battery voltage is allowed to continue dropping it will eventually be unable to wake at all If batteries are removed for changing when a LOG is due the logger will be unable to wake to execute its battery failu
37. lt a gt l a On exiting any of the keypad functions the logger always returns to the Keypad main menu Note however that the logger may autosleep if left too long without a key press There is no keypad function for putting the logger to sleep The logger autosleeps see Autosleep on page 10 Entering information Some of the keypad functions require you to enter information for example date and time password or a Selection from a menu To do so use o and or 6 until the value or option that you require comes up on the display To accept the displayed option press the key corresponding to the keypad function that you are using The logger displays a prompt such as Page 12 DL2e Hardware Reference Hardware Reference About the DL2e Logger The logger s keypad and display use lt UP gt lt DOWN gt amp lt SET TIME gt Confirming a selection Some of the keypad operations require confirmation before proceeding for example erasing data or stopping logging To confirm press the key for the keypad function that you are using In the example below press START to execute the operation you requested Pressing any other key or leaving the logger to autosleep aborts the operation The logger displays a prompt such as lt START gt confirms other keys abort Summary of keypad functions The keypad functions are named after their corresponding keys WAKE 6 0 READ SET TIME START and PRINT WAKE The WA
38. mV Zero offset 3 5 2 i e 1 75 at OmV Page 113 Sensors and Input Cards Hardware Reference Potentiometer 3 Wire connection 4 Wire connection rotary potentiometer z l ju 1 Figure 29 Sensor connections potentiometer Page 114 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Digital inputs and Counter Card type DLC1 Digital inputs and Counter Card type DLC1 Digital inputs such as the logger s on board channels 61 and 62 and the 15 channels provided on Counter Card type DLC1 may be used to record e Pulse count over a sampling interval e Frequency average pulse rate over a sampling interval In addition the logger s two on board digital channels 61 and 62 have special capabilities in being able to record e Digital status e Occurrence of events Depending on the logging program an event can be used to set the logger logging start trigger or to cause data to be recorded from specified channels data trigger See also Event trigger channels on page 23 Capabilities DL2e Hardware Reference Electrical Inputs can be one of the following e mechanical voltage free switch closures e solid state switches with leakage current in the OFF state lt lt 5uA e logic level TTL or CMOS with 5 0V to 0 7V low 0 7V to 3 5V undefined 3 5V to 50V high For minimum power consumption switches and contact sets should be of a normally o
39. may be stand alone disks cassette drives solid state data collection terminals or simple computers which are unable to run Ls2Win We don t support any specific piece of equipment and can only offer general advice here Refer to the user manual supplied with the equipment for information on how to set it to receive data from the logger and for procedures for transferring data to a computer If the device requires a sequence of control codes to initialise it for receiving data this may be set up using the Setup string for PRINT facility see the on line Help but only for PRN format data Data output in PRN format is slow If your equipment is capable of receiving 8 bit data then BIN format is strongly recommended The data can then be transferred to your computer for conversion into DAT format using the PC Remember that it is essential to use an 8 bit serial word format to collect BIN format data Data integrity checks For BIN format data the logger performs bytecount and checksum calculations and displays the results when it has finished outputting the data 13576 bytes checksum 22143 These values enable you to verify that data has been correctly received The bytecount is simply the number of bytes of data the logger has output The checksumis calculated by adding together the binary values of each byte of data ignoring overflow in excess of FFFFh Both values are displayed in decimal If the data collection dev
40. memory full e Stops logging data of the relevant data type TIMED TRIG 61 or TRIG 62 e Compiles a malfunction report e Switches the malfunction warning relay if programmed If all areas of the logger s memory are full the logger also stops logging This is reported on the Logger panel of the PC s DL2 Control Panel and in the status report displayed on the Front Panel Sensor malfunctions DL2e Hardware Reference The logger detects three categories of sensor malfunction over range noisy and outside limits If they occur during a channel report they are simply reported in error messages On detecting a sensor malfunction while logging data the logger takes the following action e Flags the logged data with the appropriate flag see on line Help e Compiles a malfunction report indicating the type of sensor malfunction and if it is the first malfunction recorded for that particular channel the date and time Note that the malfunction report is more specific than the flags attached to data or error messages displayed in the Sensors status report e Switches on the malfunction warning relay if programmed Note The logger cannot detect errors whist issuing a sensors channel status report That is data are not flagged and the malfunction report and malfunction warning relay are not affected by malfunctions detected during a Sensors status report even if the logger is logging Over range An over range condition occ
41. prevent the logger recording drifting and meaningless readings a high value e g IMQ resistor R1 should be fitted to force the potentiometer output to OV when the wiper is in the gap between the windings Programming Issues When programming a sensor type or entering measurement details for a lt Custom sensor type gt proceed as follows in the Measurement tab of the Sensor Type or Channel Properties dialog DL2e Hardware Reference 1 2 In the Measurement tab select Electrical Measurement Voltage If programming a sensor type also select Connection Requirement Potentiometer There is no need to enter any information about bridge excitation the LFW1 excitation voltage is applied to the V terminal automatically When entering a conversion factor a to obtain the fractional position of the potentiometer wiper set the conversion factor equal to the excitation voltage b If using long cable lengths measure the excitation voltage across the sensor to account for any voltage drop in the wiring c For wind vanes and other rotary potentiometers refer to sensor type Windvane type WD1 potentiometric supplied in the standard Delta T sensor library It has a conversion factor and zero offset for a rotary potentiometer with a 3 5 gap centred on the 0 position excited with the factory set voltage of 1 0486V The example below shows how these are derived Conversion factor 1 0486 360 3 5 2 941
42. the WAKE key An incoming signal at the logger s RS232 port wakes the logger This occurs when you communicate with the logger from your PC using the DL2 Control Panel which is installed on your desktop as part of Ls2Win Page 9 About the DL2e Logger Hardware Reference Logging Putting the logger to Sleep The asleep state is the logger s preferred state with low power consumption for battery conservation The logger automatically sleeps if it has woken specifically to LOG EVENT or WARM UP i e provided that it is not also busy communicating or operating under keypad control In other situations the logger autosleeps if it receives no input from a user i e a key press or communication via its RS232 port within a reasonable period of time There is no manual method of putting the logger to sleep from the keypad the logger is simply left to autosleep The logger can be put to sleep by a warm reset see page 16 but this method is not recommended for routine use Autosleep The logger autosleeps in the following conditions After 10 seconds when displaying the Keypad main menu if no key is pressed Within a few seconds if the logger is woken by noise at its RS232 port such as may occur if the power supply to a printer or computer is switched while connected to the logger The logger discriminates between noise and a genuine attempt to communicate by waiting a few seconds for further signal After one or two minutes
43. the logger s current password by retrieving the logging program from the logger Page 17 About the DL2e Logger Hardware Reference Setting the logger s clock Setting the logger s clock The logger has an internal clock that marks the date and time of all logged data The date and time can be set either from the program or from the front panel keypad You cannot set the clock while the logger is logging Leap Years The logger does not keep track of years and cannot identify leap years February is always assumed to have 28 days In a leap year the logger s date has to be set to the correct date manually after 29th February Using Ls2Win See the on line Help in the PC s DL2 Control Panel program Using the keypad display At the Keypad main menu press SET TIME The logger displays the following messages l required lt SET TIME gt use lt UP gt lt DOWN gt amp lt SET TIME gt The logger displays the date and time amp lt SET TIME gt date 28 01 The date is in European day month dd mm or American month day mm dd format depending on the setting of the 50 60 switch see Electrical mains environment on page 48 The time is formatted as hours minutes seconds hh mm ss Use and Tto adjust the value indicated by the cursor and press SET TIME when the displayed value is correct The cursor then moves onto the next field Note that the first value that you set is always the
44. the logger is logging the selected channel s show the accumulated count without affecting logged data If the logger is not logging the counter is reset to zero before returning a Channel Report Using the READ function an updated accumulating count is displayed DL2 Control Panel displays only a single value and not an accumulating count If not logging this is normally zero unless you apply a high frequency input signal Frequency type channels The logger samples frequency inputs over 1 2 second periods Hence it has a resolution of 2 Hz for this purpose e g for an input signal of 1 Hz the display alternates between 0 and 2 Hz Note that this does not apply for logged data when the resolution of frequency channels corresponds to the selected sampling interval Relay channels The status of a relay channel MAL OUT and WRM functions is either ON or OFF Using the keypad READ function the relays can be exercised for testing purposes see Using the keypad display on page 23 Sensors powered through warm up relays are normally only powered up during the warm up periods specified in the logging program To obtain valid readings from a warmed up channel the warm up relay has to be switched ON Warm up relays are aautomatically switiched ON when you select a channel and press Read Now in the Sensors panel of the DL2 Control Panel Remember you must manually switch warm up relays ON when using the keypad READ functi
45. the screw terminal block can be single ended or differential see Voltage single ended on page 86 or Voltage differential on page 89 Fit link L1 if required Selecting divider resistor values e Use precision resistors e Select Ry to be lt 24kQ Ri e Select Ry such that Vinx lt 2V Ri R2 e Ensure the voltage source can drive an impedance of Rj R2 Most voltage sources will drive a 10kQ 100kQ combination Calibrating the divider optional e Program the divided channel with sensor code VLT e Apply a precisely known voltage V n and READ the channel to obtain Vead Vread e The conversion factor for configuring the logger is then Programming Issues When programming a sensor type or entering measurement details for a lt Custom sensor type gt proceed as follows in the Measurement tab of the Sensor Type or Channel Properties dialog 1 Select Electrical Measurement DC Voltage 2 If programming a sensor type also select Connection Requirement as described in Voltage single ended or Voltage differential sections 3 Enter suitable conversion factor and offset or linearisation table for converting the input signal seen by the logger ie scaled by R1 R1 R2 or determined by calibration to engineering units Page 92 DL2e Hardware Reference Hardware Reference Accuracy Remarks See also DL2e Hardware Reference Sensors and Input Cards Voltage up to 50V DC T
46. units time battery and memory condition and status messages without disturbing logging Memory Highly reliable 2 battery backed RAM Expandable from 64K to 128K timed readings Automatic RAM check Data format ASCII easily loaded into spreadsheets and other popular software such as Excel etc Transmitted readings are date time stamped labelled in engineering units with errors flagged Data files created by the Ls2Win are comma separated Interface RS232 Serial interface up to 9600 Baud Up to 10 000 readings transferred per minute without disturbing logging Computers amp Software The logger Windows software LS2Win enables a PC to communicate with the logger edit logging programs and collect accumulated data To operate the logger from your PC you need the following e A PC running Windows 95 98 2000 or NT4 0 Service Pack 4 or later e One free RS232 serial port e CD ROM drive required for installation e atleast 16M RAM memory and 5M of hard disk space e Logger PC RS232 cable Type LRS1 available from Delta T or you can make one up See Communications cables on page 51 e Ls2Win distribution disk Power 6 internal AA alkaline cells provide power for 500K readings or 24 hours of keypad LCD or RS232 interface operation The internal lithium cell will retain memory for 2 months in the event of a power supply failure DL2e Hardware Reference Appendices Appendix A DL2e Technical Specific
47. 0mA transducer 2 wire 4 wire card LFW1 resistance 4 wire resistance 50 60 switch 6 wire bridge AC card ACD1 Page 156 30 31 30 31 69 61 69 125 63 101 61 69 109 63 104 104 125 75 T3 63 106 48 151 109 73 AC Excitation card ACS1 accuracy analogue a worked example Accuracy 2 wire resistance measurement 3 wire resistance AC Voltage analogue arithmetic current measurement DC Voltage digital channels effects of moisture PT100 measurement resistance Resistance resistance measurements thermistor measurement thermocouple thermocouple measurement voltage divider voltage measurement accuracy a worked example ACD1 ACS1 AC excitation card ACS1 AC Excitation card Analogue accuracy input card signal analogue measurements connections Anti static precautions Asleep Attenuator card LPR1 Auto print ending Autoranging effect on logging speed Autosleep disabling Ave too large Awake Backup battery Bad cold jn Battery backup Index 83 147 144 101 104 139 145 148 99 139 118 132 146 140 63 129 133 135 93 145 147 61 83 61 145 61 60 66 49 9 89 80 35 35 150 10 12 25 42 25 42 DL2e Hardware Reference Index failure life life expectancy low replacing voltage Battery pack rechargeable Baud rate Baud rate selector switch Bias resistors Bridge 3 wire 6 wire bipolar common mode voltage comple
48. 1 67 14 152 152 59 55 55 53 58 128 129 152 133 55 152 135 101 18 20 30 10 21 30 21 34 34 96 92 80 75 96 78 61 145 69 73 75 89 76 DL2e Hardware Reference Index resolution single ended up to 50V DC Wake WAKE function Warm reset WARM UP DL2e Hardware Reference 145 70 75 86 80 92 9 13 21 16 9 10 24 Warm up relay Malfunction WARNINGS Warranty and Service Wind vane XON XOFF 22 24 121 25 44 48 58 113 36 Page 161
49. 300 275 250 175 143 0950 DL2e Hardware Reference Page 153 Appendix D Resident linearisation tables Appendices Thermocouple tables Temp C is the temperature difference between hot and cold junctions Output mV for sensor code and thermocouple type TCI type J TCK type K TCT type T Iron Constantan Chromel Alumel Copper Constantan fais 3 923 3 852 3 656 3 553 3 378 3 242 3 089 so as ow 1819 1 527 1 475 0 000 0 000 0 391 0 798 0 789 1 196 1 611 2 022 2 035 2 465 2 908 3 351 3 813 4 095 4 277 4 508 4 749 5 221 5 112 6 204 6 702 6 539 7 207 6 939 7 718 8 235 8 751 200 10 777 8 137 9 286 Page 154 DL2e Hardware Reference Appendices Appendix E Identifying components on cards To identify component positions on a card relating to a specific input channel refer to the table below e debounce capacitors on a DLC1 e shunt and divider resistor positions on a LPR1 or LPR1V LPRI and LPRIY debounce capacitor shunt or divider positions 217 3247 2 6 213651 e oor O 3 233853 s Json O osa 9 dooa O 12 27 42 57 13 28 43 58 14 29 44 59 15 30 45 60 11 26 41 56 DL2e Hardware Reference Page 155 Index BIN file format BIN DAT file format DAT HFD file format HFD PRN file format PRN 15 30 switch 15 ch mode 2 wire 4 20mA transducer resistance 30 ch mode 3 wire bridge resistance 3 wire bridge 3 wire resistance 4 2
50. 7 Chapter 1 About the DL2e Logger 9 Waking and sleeping 9 Waking the logger 9 Putting the logger to Sleep 10 Autosleep 10 Logging 10 LOG EVENT WARM UP 10 Conflicting priority tasks 11 The logger s keypad and display 12 Using the logger s keypad and display 12 Summary of keypad functions 13 Resetting the logger 15 Coldbooting 15 Warm reset 16 Password 17 Setting the logger s clock 18 Using Ls2Win 18 Using the keypad display 18 Chapter 2 Interrogating the DL2e logger ______ 19 Logger status 19 Using Ls2Win 21 Using the keypad display 21 Sensors status 22 What the Sensors status provides 22 Using Ls2Win 23 Using the keypad display 23 Error status 24 Using Ls2Win 26 Using the keypad display 26 Chapter 3 Starting and Stopping Logging 22 27 Starting logging 27 Using Ls2Win 27 Using the keypad display 28 Stopping logging 29 Using Ls2Win 29 Using the keypad display 29 Chapter 4 Collecting and Erasing Logged Data_ss i WU 30 Data collection options 30 DL2e Hardware Reference Page iii Contents Using Ls2Win 32 Outputting data directly to a printer 33 Preparation 33 Checking printer operation 33 Using the keypad display 34 Auto printing 35 To stop auto printing 35 Using other data collection devices 36 Data integrity checks 36 Handshakin
51. About the DL2e Logger Hardware Reference The logger s keypad and display The logger s keypad and display Using the logger s keypad and display To use the logger s keypad wake the logger by pressing WAKE You must press WAKE while the logger is asleep Any message on the screen indicates that the logger is already awake for example communicating or performing a LOG Disconnect any serial communication cable and allow the logger to autosleep if autosleeping has not been disabled In emergency try a warm reset or as a last resort coldboot the logger see Coldbooting on page 15 On its display the logger echoes the key press lt a gt l a Keypad main menu The logger displays General Status and Malfunction Reports see Logger on page 19 and page Error status on page 24 followed by a message known as the Keypad main menu ET key if required Keypad functions You can now press any key to enter one of the logger s seven keypad functions The keypad functions are named after the logger s seven keys and are summarised opposite Note that you can curtail the General Status and Malfunction Reports at any time by pressing one of the keys If you hold the key down you can also omit the main menu message and go directly into one of the keypad functions On entering a keypad function for example READ the logger first confirms the key press by displaying the name of the selected function
52. Fig 12 4 shows how to assemble the terminal compartment cover e Ensure gaskets are fitted to the terminal panel and extension piece and that the foam sealing strip on the rear of the cover plate is in good condition replace if necessary e Thread the sensor cables through the extension piece before plugging the connectors into the terminal panel e Spread the sensor cables evenly along the bottom edge of the extension piece and fit the cover plate compressing the foam rubber seating strip against the sensor cables The terminal cover does not normally form an airtight seal owing to gaps between the foam and the sensor cables The drip in the cover plate is designed to shed rain and under most conditions further sealing is not needed If flooding or heavy spraying is anticipated seal the cable exits with silicone glue Page 55 DL2e Logger Hardware Hardware Reference Field installation ea gasket terminals sprayed with water repellent oi desiccant capsule sealed power supply socket 3 lt f cover plate EISA of f lt tain shedding r f 3 ie Leh ore 4 1 ip z j PA drip Y N foam seal on i _ rcar of drip sealed sensor cable threaded through extension piece RS232 connector mounting screw and hole Figure 5 Logger assembly for field installation In exposed situations it may be better to provide a second layer of protection by enclosing the whole logger
53. IV or ACD1 or LFW1 as above Use across screw terminals conversion factor to obtain absolute voltage values LPR1 V can be used with LACI or ACD 1 for this purpose ac voltage 0 2V i eg ACD1 dc true rms 2Vac rms crest factor 1 0 to 1 7 CURRENT 4 20mA loop shunt resistors fitted to Shunt voltage measured using LAC1 transducers LPR1 LPR1V or ACD1 or LFW1 as above Use across screw terminals conversion factor to obtain absolute current values LPR1 V may be used with LAC1 or ACD1 for this purpose photodiodes RESISTANCE 10kQ to IMQ 100k thermistor LAC1 15 ch or 30 ch 2 wire ACD1 LFW1 lt 10kQ negligible 2kQ thermistors on LAC1 15 ch or 30 ch Use short heavy cables Program channel cable resistance short leads 2 wire or 3 wire with offset to null out cable resistance ACD1 LFW1 LAC1 15 ch 3 wire connection is preferable to 2 wire peaa acpi eaa a aa junction thermistor ACD1 terminal panel significant cable 2KQ thermistors on LFW1 4 wire If LFW1 unavailable use LAC1 15 ch 3 resistance long leads wire connection in preference to 2 wire connection small changes from PT100 LFW1 4 wire with r a small changes no strain gauge LFW1 full half or 3 well defined base wire bridge value potentiometer wind direction LFW 1 potentiometric Can also measure resistance using 2 3 C relieves a granular matrix ac readings taken by card ACD1 Page 66 DL2e Hardware Reference Hardware Reference Senso
54. KE function displays a General status report e Battery voltage and expected life e Current date and time e Configuration name e Whether logging or not e Date and time of start and end of logging if appropriate e Amount of memory installed and number of stored data e Malfunction Reports battery failed memory filled and suspect data logged on any channel See Logger on page 19 for details READ The READ function is for checking a logging set up before or during logging e Displays instantaneous values on input channels e Displays status of relay and event trigger channels e Permits switching of relay channels under keypad control See page 23 for details SET TIME The SET TIME function sets the time on the logger s internal clock See Setting the logger s clock on page 18 for details START The START function starts and stops logging See Starting and Stopping Logging on page 27 for details PRINT The PRINT function can be used to e Printout data on a serial printer DL2e Hardware Reference Page 13 About the DL2e Logger The logger s keypad and display Page 14 Hardware Reference e Output data in binary file format to a data collection terminal not using Logger PC Software e Frase data See Collecting and Erasing Logged Data on page 30 for details The o function is for testing two way serial communication e g with a computer See Error Reference source not found on page Error B
55. L2e Hardware Reference Appendices Appendix A DL2e Technical Specifications Digital inputs and outputs Digital inputs All DL2e s have 2 resident 16 bit counter channels that can continuously monitor logic levels or switch closures recording digital status counts or frequency up to 100Hz or can trigger special logging sequences Relay outputs 2 SPDT relays for powering up sensors or providing alarms or malfunction warnings 1 Amp 50 V contact rating Counter Card DLC1 Each DLC1 card provides up to 15 extra 16 bit counter or frequency channels Maximum frequency 500Hz 1ms pulse for switch closures 500kHz for 5V logic level signals see page 117 for details Each channel can log up to 65 472 counts between scans DL2e Hardware Reference Page 141 Appendix A DL2e Technical Specifications Appendices Other specifications Page 142 Processing The logger can convert readings into engineering units using linearisation tables or a conversion factor and zero offset User expandable sensor library includes Delta T sensors Platinum Resistance Thermometers Thermistors Fenwal 2K 2K252 10K and 100K types and Thermocouples types J K and T Cold junction temperature measured at isothermal terminals For thermistor errors see also page 129 For Platinum Resistance Thermometer errors see page 132 For Thermocouple errors see page 133 Display A 2 line LCD shows instantaneous output from any sensor in engineering
56. O00000 SCE VgoqeCcoeecy Track links on underside cut for voltage divider Varistors LPR1V only Connections to LAC1 30 ch or LAC1 15 ch or LFW1 Figure 11 LPR1 and LPR1V supplementary input cards DL2e Hardware Reference Page 81 Sensors and Input Cards Hardware Reference Attenuator Card type LPR1 Input Protection Card type LPR1V Fitting the card in the logger Mount the card on top of the input card stack Use the standoff pillars supplied with the card For newer style loggers you may have to remove the slotted nylon nuts from the top of the stack and replace them with standoff pillars before fitting the card After locating the card on the stack screw down the nylon nuts or standoff pillars onto the protruding studs to secure the card in position Connect the card to the logger s terminal panel and an analogue card as illustrated in Figure 12 LPR1 or LPR1V LAC1 30 ch or LFW1 LAC1 15 ch Figure 12 Fitting LPR1 or LPR1V to input card stack If the LAC is set for 30 ch mode see Analogue Input Card type LAC1 on page 69 for restrictions on use of terminal groups Remarks Channels without resistors fitted or cut track links are unaffected by the LPR1 card The LPR1V can affect the logger s precision when measuring resistance using the 2 uA excitation current This is due to the capacitance of the varistors on the LPRIV Measurements with larger excitation currents are much less affected and
57. Reference Hardware Reference Collecting and Erasing Logged Data Erasing data from the logger s memory Continuous data collection as a backup By using the auto print feature see Auto printing on page 35 a data collection device can act as a backup for the logger s memory with simultaneous storage of data to the logger s memory and data collection device Note that if you auto print BIN format data you will almost certainly have to disable the logger s auto sleep feature Any spurious characters in a BIN file caused by the logger waking up will render the file completely useless Erasing data from the logger s memory Data can be erased from the logger s memory in order to clear space for more data and may be carried out while the logger continues to log It is generally advisable to check that the collected data has not become corrupted during collection before irreversibly erasing it from the logger s memory You can do this by using Ls2Win A duplicate set of data can be collected from the logger if a data collection fault is suspected As the three data types TIMED TRIG 61 TRIG 62 are stored and output from the logger independently they can also be erased independently Timed data and event triggered data are stored differently in the logger and there are minor differences when erasing Timed data You will only be permitted to erase data that has previously been collected from the logger Any data l
58. The logger reads the battery voltage each time it wakes If the voltage available to power the logger is less than 7 0 Volts e The logger briefly displays battery failure on its display e Tf logging the logger stops logging compiles a malfunction report and switches the malfunction warning relay if programmed This is to conserve any remaining battery life and avoid any risk of corrupting or losing logged data e The logger autosleeps Remarks The logger can only perform this routine if there is enough power available for the logger to wake If the power supply becomes completely disconnected the logger will be unable to take any action On reconnection of the power supply the logger will fail to report battery failure If logging the most likely outcome is a series of over run errors as the logger attempts to catch up on lost logging opportunities Page 24 DL2e Hardware Reference Hardware Reference Interrogating the DL2e logger Error status The mechanism for detecting battery failure is not the same as for reading the battery voltage when reporting Logger status The logger may not detect a battery failure even though it reports a battery voltage less than 7V or the logger may have detected a battery failure while reporting a battery voltage greater than 7V due to battery de polarisation Memory full If an area of the logger s memory TIMED TRIG 61 TRIG 62 fills up the logger e Briefly displays the message
59. User Manual for DL2e Data Logger Hardware Reference nN 1 ZEA DL2 Progam New DL2 DL2 Dataset Dataset Import dit Control Panel Viewer Wizard Version 3 Delta T Devices Ltd VERSION Document code DL2 UM 05 03 Version 3 Issued 15 Dec 2000 See also Getting Started Ls2Win on line Help TRADEMARKS IBM PC PC XT PC AT PS 2 and PC DOS are registered trademarks of International Business Machines Corporation MS DOS Windows and Windows NT are registered trademarks of Microsoft Corporation Lotus 1 2 3 is a registered trademark of Lotus Development Corporation Hayes is a registered trademark of Hayes Microcomputer Products Inc COPYRIGHT This manual is Copyright 1992 1993 1996 2000 Delta T Devices Ltd 128 Low Road Burwell Cambridge CB5 OEJ UK All rights reserved Under the copyright laws this book may not be copied in whole or in part without the written consent of Delta T Devices Ltd Under the law copying includes translation into another language ELECTRO MAGNETIC COMPATIBILITY The DL2e Logger has been assessed under the European Union EMC Directive 89 336 EEC and conforms with the following harmonised emissions and immunity standards EN 50081 1 1992 EN 50082 1 1992 Contents Contents iti Hardware Reference 7 About this manual 7 Other Documents and Help
60. acy On board cold junction thermistor The logger s on board cold junction thermistor is specified to an accuracy of 0 1 C for 0 C to 70 C and 0 13 C from 20 C to 0 C Logger contribution to thermistor errors The table below shows the maximum logger contribution to thermistor errors for common thermistors measuring a temperature in the range 20 C to 60 C Maximum C errors due to logger operating temperature Connection LAC1 15 ch or LAC1 30 ch LFW1 Logger Temp 20 C 20 C to 20 C 20 C to 60 C 60 C Maximum C errors due to logger 2k iad 0 14 C 0 17 C 1 24 C 1 25 C 0 29 C 0 62 C 0 47 C 0 74 C 100k 0 39 C 0 93 C 0 39 C 0 93 C See Appendix B for a worked example of a logger accuracy calculation Errors due to cable resistance With 2K and other low value thermistors on long thin cables the cable resistance may cause slight errors The increased resistance reading causes a reduction in the temperature reading The following table shows the C error per ohm of cable resistance Thermistor type C error per extra Q resistance at temperature DL2e Hardware Reference Page 129 Sensors and Input Cards Hardware Reference Thermistors Note that e The effect is temperature dependent and most pronounced at higher temperatures when the thermistor resistance is low e For 2 wire connection the resistance of both connecting leads must be included For 3 wire connection only the retu
61. ading readings With sensors of higher resistance or if there are fewer than 6 in a terminal group the voltage may be increased to give more sensor output and sensitivity Adjusting the voltage source e To increase the voltage turn trimmers A or B clockwise Beware of creating common mode problems by applying too large an excitation voltage to bridge sensors see Common mode voltages on page 96 e To reset the voltage source turn trimmers A and B fully anti clockwise to reset the voltage sources to 1 0486V This value is precise and repeatable Programming Issues DL2e Hardware Reference Programming an Input Channel Select Input Card Type for the channel group that is connected to the LFW1 depending on resistance offset setting e No offset LFW1 no offset e Factory set offset LFW1 20C PT 100 offset e Alternative offset LFW1 custom offset The Input Channel tab of the Channel Properties dialog for this channel group will then offer suitable sensor types in the Sensor Type list or if you select lt Custom sensor type gt the Measurement tab will offer suitable options in the Electrical Measurement list Programming a Sensor Type In the Measurement tab of the Sensor Type Properties dialog select an Electrical Measurement Connection Requirements combination from one of the following groups No offset e DC Voltage Single ended Differential low CM Differential high CM
62. agged as over run but also the following reading which will be sampled over a shorter than nominal sampling interval The process responsible for over runs can also cause the logger to get a bit behind with logging but not sufficiently to register an over run with similar consequences for accuracy The logger assigns a high priority to logging of timed data and over runs only occur if event triggered logging conflicts with timed logging or if the logger is required to log data continuously at a rate of more than a few channels per second Analogue channels The time taken to take analogue readings is indeterminate A typical analogue reading takes 100ms whereas an extreme case of auto ranging can take 300ms Within any group of channels with the same sampling interval the logger reads counter and frequency channels before analogue channels in order to minimise this effect This reading order is reflected in the arrangement of channels in data files Waking The logger takes approximately 250ms to initialise itself when waking This delay is repeatable for each waking of the logger but the delay doesn t occur if the logger is already awake when required to log data Page 118 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Digital inputs and Counter Card type DLC1 On board E 35 to SoU digital channels 3 5 to SOU 5 to 0 7V Figure 33 Sensor connections digital channels Start tri
63. ailable in each of the following component programs of the Windows software Ls2WIN e DL2 Program Editor to create and edit logging programs e DL2 Control Panel to control and monitor the logger e Dataset Import Wizard to retrieve logged data into Microsoft Excel e DL2 Dataset Viewer to view raw data files once saved to your PC Logger status information is displayed on the Logger and Datasets panels in the DL2 Control Panelon your PC It also appears transiently on the DL2e Front Panel as part of the general status report when you wake the logger PROM version The PROM version is only shown on your PC in the Logger panel in the DL2 Control Panel It does not appear on the logger s Front Panel Display Battery voltage and life expectancy DL2e Hardware Reference The reported battery voltage is the voltage available to power the logger The voltage available to power the logger is not always the full battery or external power supply voltage being reduced by a diode drop approximately 0 6V in the following cases e Ifthe logger is powered from an external power supply e Ifthe logger is powered from its internal batteries with the power supply selector switch set to EXTERNAL The reported battery voltage is intended as a guideline only Fluctuations may occur due to polarisation effects in the logger s internal alkaline cells In particular the batteries appear to recover during a long period of inactiv
64. al Measurement Voltage b If programming a sensor type also select Connection Requirement Bridge c There is no need to enter any information about bridge excitation the LFW1 excitation voltage is applied to the V terminal automatically 2 Current excited bridge a Inthe Measurement tab select Electrical Measurement Resistance b If programming a sensor type also select the appropriate Connection Requirement for the intended LFW1 card setting ie 4 wire no offset 4 wire 20C PT100 offset or 4 wire custom offset c For Excitation select the largest excitation current that matches the sensor s specification 3 Enter a linear conversion factor and zero offset or a linearisation table which can be derived by calculation ie from known sensor characteristics for example sensor output mV per volt excitation or by calibration ie apply known stimuli to the sensor and note the logger resulting For a current excited bridge you will need to enter conversion factor and offset or linearisation table in resistance units so you may need to scale the bridge output accordingly 4 Alternatively the logger can record raw voltage outputs from bridge sensors and you can calibrate the data after collecting it to a disk file for example using a spreadsheet To program a channel for 3 wire PT100 measurement 1 Select Input Card Type LFW1 no offset for an input channel group 2 Inthe Inpu
65. ards Hardware Reference Bridge measurements e Set the R PRT switch to the R position When switched to PRT the logger s common mode rejection ratio CMRR can be substantially degraded Excitation Bridge output is proportional to the applied excitation voltage Sensitivity is often quoted in mV V that is millivolts of output per volt of excitation Voltage excitation A voltage source is automatically applied to the V terminal of each of the 6 channels in a terminal group whenever any channel in the terminal group is being read e You can adjust the voltage source for each of the two channel groups on the LFW1 if required see Voltage sources on page 78 e Ensure the current limiting LED indicator does not light This indicates current limiting and that the voltage source output is reduced Current excitation e Connect the bridge to the I terminal instead of the V terminal Figure 27 Sensor connections bridge measurements and program the channel as a resistance channel with the required excitation current see below The excitation current is only applied to a channel while it is being read as for normal resistance measurements Bridge completion resistors Half and 3 wire bridges require precision bridge completion resistors mounted on the logger s screw terminal blocks These should be precise and stable for example 0 1 1Sppm C Half bridge e Mount resistors R3 and R4 on the logger s screw term
66. are preferable for measuring resistance s smaller than 100 kQ track link from terminal input panel card UR only on LPR1U Figure 13 LPR1 LPR1V input stage schematic diagram Page 82 DL2e Hardware Reference Hardware Reference Sensors and Input Cards AC Excitation Card type ACS1 AC Excitation Card type ACS1 The ACS1 card provides AC excitation for up to 60 AC resistance sensors such as gypsum block or granular matrix soil moisture sensors The card applies 2 0V square wave excitation 125Hz 30Hz to each selected channel via a 10 kQ 1 socketted resistor and a 10 uF bipolar electrolytic isolating capacitor The ACS1 card operates from a supply of 7 15 Vdc and has a quiescent current consumption of lt 10mA Capability Channels The isolating capacitors prevent any dc polarisation of the sensors An ACD1 is used to measure the ac voltage across the sensor which can be interpreted as a resistance see below Channels to be supplied with the AC excitation must have the corresponding shorting link and resistor fitted on the ACS1 card see Figure 16 ACS1 circuit board channel details To measure non AC excited sensors on other input channels when the ACS is fitted the corresponding socketted resistors and shorting links should be removed This is necessary for ACD1 channels measuring DC volts or resistance or any other kind of sensor and for channels connected to LAC1 DLC1 and LFW1
67. articularly of low resistance values A resistance offset can be applied for accurately measuring small changes of resistance from a stable and repeatable base value This method is particularly recommended for PT100 platinum resistance thermometer measurements Setting up Connect one or two ribbon cable from any terminal group to either or both positions on the card Simple resistance measurements Set the R PRT switch to the R position PT100 offset 20 C For PT100 measurements optimised for environmental temperature measurements in the range 20 to 60 C Set the R PRT switch set to the PRT position Fit jumper L1 in the PRT position Other resistance offsets Set the R PRT switch set to the PRT position Fit jumper L1 in R4 position Fit resistors R1 and R4 and calibrate as described in Calibration of resistance offset on page 76 Programming Issues When programming a sensor type or entering measurement details for a lt Custom sensor type gt proceed as follows in the Measurement tab of the Sensor Type or Channel Properties dialog 1 2 In the Measurement tab select Electrical Measurement Resistance If programming a sensor type also select the appropriate Connection Requirement for the intended LFW1 card setting ie 4 wire no offset 4 wire 20C PT 100 offset or 4 wire custom offset For Excitation select the largest excitation that can accommod
68. ate the range of resistance s that you need to measure If you have chosen 4 wire 20C PT100 offset or 4 wire custom offset when entering conversion factor and offset values or linearisation table bear in mind that the logger measures a resistance which is lower than the real resistance value by the value of the resistance offset To program a channel for 4 wire PT 100 measurement with resistance offset 1 2 Accuracy Select Input Card Type LFW1 20C PT 100 offset for an input channel group In the Input Channel tab of the Channel Properties dialog select sensor type Platinum Resistance Thermometer type Pt100 4 wire 20C PRT offset which is a Delta T approved sensor type provided in the standard Ls2Win sensor library The logger s resistance measurement accuracy is fully described in Appendices A and B Page 106 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Resistance 4 wire Remarks Switching in the resistance offset has the effect of degrading the common mode performance of differential voltage measurements on the card Avoid mixing differential voltage measurements and offset resistance measurements on the same LFW1 See also Bridge measurements for accurately measuring small changes in resistance e g for strain gauges see Bridge measurements on page 109 resistance offset resistance offset PT 100 user set resistance offset none RZPRT sui
69. ation parameters must be set to match identically To change the logger s communication parameters use switches on the main board See Figure 2 Main circuit board layout with the following options Baud rate 9600 4800 2400 1200 600 300 150 75 Move the baud rate selector switch to the appropriate position For use with DL2 Control Panel this setting must match the baud rate selected in the DL2 Connection Properties dialog You will be prompted automatically when creating anew DL2 Control Panel or you can select the Properties command File menu to select a baud rate for an existing DLControl Panel Data bits 7 DIP switch 1 OFF 8 DIP switch 1 ON If using DL2 Control Panel select 8 data bits Stop bits 1 fixed Parity None DIP switch 2 OFF Even DIP switch 2 ON DIP switch 3 OFF Odd DIP switch 2 ON DIP switch 3 ON If using DL2 Control Panel select None Factory settings 9600 baud 8 data bits 1 stop bit and no parity These are also the default settings for the DL2 Control Panel Note that changes in the baud rate setting take effect immediately Changes in DIP switch settings take effect only when the logger wakes unless the logger is executing the echo test o see Error Reference source not found on page Error Bookmark not defined or printer test t see Outputting data directly to a printer on 33 in which case the change is immediate Page 50 DL2e Hardware Reference Hardwar
70. ations Environmental Operating temperature 20 C to 60 C IP65 weatherproof case with desiccant and humidity indicator Dimensions and weight Size 280 x 220 x 140 mm Weight 2 7kg Rechargeable battery pack LBK1 Battery type Dryfit A200 or equivalent sealed lead acid with thixotropic electrolyte gel Voltage 12V nominal 12 6 12 9V fully charged 10 5V fully discharged at 20 C Capacity 1 8Ah nominal sufficient for 36 hours operation awake or 1 year asleep at 20 C less at higher temperatures Charging conditions 16 hours at constant voltage which is temperature dependent 13 98V 0 18V at 15 C 13 80V 0 18V at 20 C 13 65V 0 18V at 25 C Important do not exceed the specified charging voltage Fuse 1 Amp 20x5mm cartridge fuse Sealing IP65 Dimensions amp Weight 220 x 85 x 85 mm 1kg Electro Magnetic Compatibility The DL2e logger has been assessed under the European Union EMC Directive 89 336 EEC and conforms with the following harmonised emissions and immunity standards EN 50081 1 1992 EN 50082 1 1992 DL2e Hardware Reference Page 143 Appendix B Accuracy of logger readings Appendices Appendix B Accuracy of logger readings There are several categories of error that should be considered when estimating the accuracy of logger readings Analogue errors These are due to the inherent limitations of the electronic components used in the logger Arithmetic errors
71. atteries Do not remove the logger s internal batteries Internal batteries in good condition are essential to provide backup power whenever the battery pack is removed for recharging Recharging Even while asleep and not logging the logger draws a small amount of current to power its clock and memory In the absence of any other power supply this has to be supplied by the lithium cell which will eventually get discharged and fail as a backup battery The internal batteries also allow the battery pack to be removed for recharging without interrupting logging The battery pack should be recharged as soon as possible after the logger reports a battery voltage of less than 10V Note that the reported battery life is based on the discharge curve of alkaline cells and gives no indication of the charge state of the battery pack To recharge the battery pack DL2e Hardware Reference Remove the battery pack from the logger disconnect the power supply lead and loosen the knurled thumbscrews Plug the charging lead into the battery pack socket Connect the other end to the charger RED Charge for 16 hours in a well ventilated space according to the specifications below A suitable battery charger is available from Delta T Page 47 DL2e Logger Hardware Hardware Reference Electrical mains environment Charging specifications Voltage The battery pack must be charged at a constant voltage which is temperature dependen
72. attery pack Components The battery pack comprises e battery unit lead acid battery plus enclosure e power supply lead for connecting to the logger s external power supply socket e charging lead Loggers supplied with battery packs have the rubber gasket and four threaded inserts ready fitted Otherwise the battery pack is supplied with e threaded inserts e 5mm Allen key e M6x6 hex socket cap screw e rubber gasket Page 46 DL2e Hardware Reference Hardware Reference DL2e Logger Hardware Rechargeable battery pack type LBK1 Assembling the battery pack Battery packs ordered together with loggers are supplied assembled ready to use Otherwise Screw the four threaded inserts into their bushes just as the threaded inserts which retain the terminal compartment cover Use the Allen key and socket cap screw as illustrated above Take particular care to ensure that the inserts are fitted centrally and squarely in their bushes Fit the rubber gasket in its slot If desired use an adhesive such as cyanoacrylate to prevent it falling out when the battery pack is removed for recharging Fitting the patery pack to the logger Locate the battery pack over the gasket and inserts and tighten the thumbscrews finger tight Plug the power supply lead into the battery pack and logger s external power supply sockets Set the logger s power supply switch to EXTL Figure 2 Main circuit board layout Internal b
73. cations Appendices Resistance readings dc via LAC1 ACD1 or LFW1 Autoranging 12 bit voltage readings with programmable 2 20 200 or 2000UA excitation giving IMQ full scale or lt 0 01Q resolution Accuracy As voltage readings with additional errors 2 uA current 0 3 full scale 0 6 to 50 C Other currents 0 05 0 1 2 Wire LAC1 only 20 6Q typical additional offset See also Appendix B Resistance readings ac Using ac excitation card type ACS1 amp ACD1 Accuracy Overall system accuracy 2 for R 500 to 30 000 Ohms Input protection Analogue inputs withstand 15V continuously and much higher voltages in brief pulses For additional protection see LPR1V below Attenuator Card LPR1 For use with LAC Analogue Card only Provides sockets for signal conditioning resistors for 30 channels Resistor positions may be left vacant or resistors fitted in shunt or divider configuration respectively for measuring currents up to 0 1 Amp or voltages up to 50V Input Protection Card LPR1V Connects transient absorbing varistors to 30 LAC1 Analogue Card inputs or 12 LFW1 4 Wire Card inputs for additional input protection Also provides socketted resistor positions for signal conditioning only suitable for this application when used with LAC1 see LPR1 above Avoid using LPR1V when measuring resistances gt 100KQ as varistor leakage currents may be a source of significant error Page 140 D
74. ce measurements 3 wire current excited A wire link can be fitted on the screw terminal block for 2 wire measurements with better performance than 30 ch 2 wire measurements does not suffer 20Q offset error Setting up 15 30 switch Set to 15 position Ribbon cables Connect from any terminal group on the terminal panel to the card connector marked differential Make no connections to the other two connector on the card Programming Issues Programming an Input Channel Select Input Card Type LAC1 15 channel for the channel group that is connected to the LACI card The Input Channel tab of the Channel Properties dialog for this channel group will then offer suitable sensor types in the Sensor Type list or if you select lt Custom sensor type gt the Measurement tab will offer suitable options in the Electrical Measurement list Programming a Sensor Type In the Measurement tab of the Sensor Type Properties dialog select one of the following Electrical Measurement Connection Requirements combinations e DC Voltage Single ended Differential low CM Differential high CM e Resistance 2 wire 3 wire e Thermocouple Single ended Differential low CM Differential high CM 30 ch mode Capability Channels 15 or 30 channels one or two terminal groups DL2e Hardware Reference Page 69 Sensors and Input Cards Hardware Reference Analogue Input Card type
75. ce of one or more arms of the bridge to be measured A precise excitation voltage or current is applied across one diagonal of the bridge and the resulting voltage across the other diagonal of the bridge is a measure of any imbalance in the bridge resistors The output of the bridge is proportional to the applied excitation Bridge sensitivity is often quoted in mV V that is millivolts output per volt of excitation Full bridge In a full bridge all four bridge resistors are mounted remotely from the logger One or more of the resistors are sensing devices with a resistance that changes in response to the applied stimulus The remaining resistors are bridge completion resistors In some arrangements dummy sensors are used as bridge completion resistors to cancel out temperature and other environmental effects In half and 3 wire bridges bridge completion resistors are mounted on the logger s terminal panel For economy groups of similar half or 3 wire bridges can share bridge completion resistors Half bridge In a half bridge two resistors R1 and R2 effectively act as a potential divider when excited by a voltage or current source The completion resistors R3 and R4 provide a reference voltage so that the logger reads zero when the bridge is balanced 3 wire bridge A 3 wire bridge enables sensitive measurement of changes in resistance with minimal cable resistance errors and only 3 wires to the sensor In fig Figure 27 R1 is th
76. contributes to resistance error For economy of wiring a single heavy duty low resistances return lead can be shared between several sensors e Use 4 wire connection to an LFW1 which virtually eliminates cable resistance errors and is suitable for measuring resistance s down to a few ohms Measuring small changes in resistance Some sensors require accurate measurement of small deviations from a known base resistance value Examples are strain gauges and platinum resistance sensors Strain gauges are commonly connected in bridge circuits An excitation voltage or current is applied to the bridge and if the values of the 4 resistors in the bridge are symmetrical the output voltage is zero Small changes in resistance unbalance the bridge causing a differential output voltage proportional to the imbalance and the excitation The LFW1 card can provide precision excitation for bridge measurements see Bridge measurements on page 109 Alternatively you can provide excitation from a precision voltage source and measure the bridge output as a simple voltage beware of common mode problems See Power supplies to sensors on page 64 Another technique available using the LFW1 card is an offset for resistance measurements a base resistance value is subtracted from the sensor resistance this is done electrically on the LFW1 card and the logger measures the deviation from the base resistance value This arrangement is sometimes known as
77. d a negative voltage when it needs data transmission to pause This pin should be connected to the CTS pin of the logger The connections required are shown below for a typical printer with a 25 pin D connector The pin numbers given are for one of the most common printer RS232 port configurations but printer RS232 ports are not standardised and you should refer to your printer manual to determine which pins carry which signals Logger Printer Pin no Pin no Signal Connection Signal Typical a pin 2 pin pin no Een contrel i typically control typ typically pre do Page 52 DL2e Hardware Reference Hardware Reference DL2e Logger Hardware Testing communication Testing communication The following test procedure may help you solve logger computer communication problems Connect the logger to your computer Start a terminal program using a baud rate that matches the logger s baud rate If using Windows HyperTerminal proceed as follows From the Start menu select Programs Accessories Hyperterminal HyperTerminal In the Connection Properties dialog enter a name for the connection eg 9600 baud on COMI In the Connect To dialog select the serial port to which your modem is connected in Connect using list In the Port Settings tab of the COMx Properties dialog select Bits per second Data bits and Parity to match the settings that you wish to use Stop bits 1 Flow control None and click OK Terminal mo
78. d with channel 61 as a start trigger channel see on line Help When started from the logger s keypad or using the immediate start option via the PC the logger will delay logging until it receives a signal on channel 61 Note that this is different from the action of a data trigger After an event triggered start the logger proceeds logging as if an ordinary immediate start had occurred acquiring timed data at regular intervals with no further inputs required on the start trigger channel A data trigger causes the data to be logged whenever an input is detected on the data trigger channel in parallel with timed data Using Ls2Win Click Start or Re start in the Logger panel of DL2 Control Panel then make a selection from the available options in the Start Logging dialog See also the on line help DL2e Hardware Reference Page 27 Starting and Stopping Logging Hardware Reference Starting logging Using the keypad display Event triggered start only For a triggered start first program channel 61 as a start trigger see on line Help Then proceed as for Immediate start Immediate start At the Keypad main menu press START lt START gt If the logger is already logging you are asked if you want to stop logging see Stopping Logging on page 29 I already logging to STOP If data exists from a previous logging session you will be asked if you want to erase it l 28 readings to be erased If the logger c
79. d with the date and time of the last line of data which was collected on the previous occasion and which will not be collected again Number of data to be output Your logger may contain more data than you can handle in a single disk file If you don t want to collect all the data stored in the logger into a single file you can specify the number of readings you require You can then collect another batch of data that follows on from the first file and so on DL2e Hardware Reference Page 31 Collecting and Erasing Logged Data Data collection options Hardware Reference Note that the number you specify will be only approximate as the logger has to output complete lines of data A line of data is a group of readings that have been stored on any single occasion and appear on a single line in a printout or DAT file The size of a data file depends on the logging program as well as the number of data it contains For a given quantity of data a configuration with a small number of input channels and hence a lot of lines will produce a larger data file than a configuration with many input channels and hence few lines Size of files The table below shows the number of bytes in each element File Header Channel Header Date time and Reading in the various formats of logger data files You can calculate the size of data files from File size bytes r x number of readings d x number of lines of data c x numbe
80. data type and starting point of the data to be collected These options and the techniques themselves are described below Two related features that you may find useful are e Auto printing the logger can be set up to output data automatically whenever it stores new data to its memory see the on line Help e Auto wrap or Overwrite mode automatic overwriting of old data when the logger s memory fills up see the on line Help for the DL2 Control Panel Note that data stored in the logger s memory cannot be displayed directly on the logger s display or computer screen It must first be collected to a disk file using Ls2Win Data collection options Page 30 Data type The logger partitions its memory and stores and outputs timed and event triggered data separately Ls2Win refers to these as TIMED TRIG 61 and TRIG 62 datasets The logger refers to tham as data types File format The DL2e system makes use of four data formats referred to by their associated file name suffices BIN HFD DAT and PRN In Ls2Win you will see references to bin hfd and dat formats If you use the keypad to output data you will be offered PRN and BIN formats BIN HFD The BIN format is a binary format containing compressed data 2 bytes per reading as retrieved from the logger using a fast binary protocol or output directly from the logger using the PRINT function DL2e Hardware Reference Hardware Reference
81. de Echo test DL2e Hardware Reference At the Communication Options window press lt Ctrl gt T This puts the computer into Terminal Mode displaying the headin gacross the top of the screen TerminalMode Anything you now type at the computer keyboard will be sent to the computer s serial port and not directly to the screen The screen displays information arriving at the computer s serial port KB2 Wake the logger using WAKE and at the keypad main menu press lt o gt briefly This puts the logger into echo test mode l lt UP gt I echo test Press briefly Don t hold lt o gt down or the logger will carry out the Hayes modem initialisation routine If you do not obtain the echo test message but instead get a different message on the display Initialising Hayes modem or Communicating allow the logger to autosleep and start again In echo test mode the logger simply displays any character it receives at its RS232 port and echoes it back to the Transmitted Data line of its RS232 port Press a few keys on the computer keyboard not too fast Each character will be sent to the logger and should now appear on the logger s display The logger then echoes i e re transmits each character and they should appear unaltered on the computer screen Anything you type should thus appear on the computer screen having been to and from the logger Page 53 DL2e Logger Hardware Testing communication Pag
82. de additional input protection Setting up Fitting precision resistors Precision resistors should only be fitted to LPR1 and LPR1V cards connected to a LACI card LAC1 can be set for 15 ch or 30 ch operating mode Resistor positions are labelled on the card with channel numbers 1 30 If you need to fit resistors to channels outside this range refer to Appendix E Voltage divider resistors Cut track links on the underside of the card for channels to be fitted with divider resistors and fit resistors R4 and R3 Select R and R3 so that e R1I lt 24kQ Ri e xXVinmax lt 2 097V Ri R2 e Note that the logger s effective input impedance for the divided channel is then R R This may affect the measurement of high impedance voltage sources e Precision resistors are recommended 0 1 resistors give an additional worst case error of 0 2 Shunt resistors Ensure the track link on the underside has NOT been cut Fit resistor R only Select Ry so that _ 400x10kQ 2000 V e Ensure that the current source can drive Ri X Jinmax max e Precision resistors are recommended 0 1 resistor gives 0 1 additional error e To avoid additional contact resistance error don t select too low a value Page 80 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Attenuator Card type LPR1 Input Protection Card type LPR1V Ribbon cable from Ribbon cable from any terminal group any terminal group LALLE
83. de of the deviation of the reading from the zero offset Rounding errors for linearised data in engineering units Deviation from offset 0 to 40 95 40 96 to 327 6 327 68 to 2620 8 2621 44 to 20966 4 For example for sensor code PT4 a resolution of 0 01 C is available over the environmental temperature range of 20 C 40 95 C i e 20 C to 60 C Page 149 Appendix C Calculating the speed of data readings Appendices Appendix C Calculating the speed of data readings Page 150 The time it takes for the logger to complete one cycle of readings a scan is made up of the scan overheads at the start and end of each cycle plus the time taken for each of the various channel readings in the scan and their associated processing functions In most applications where channels are to be sampled at less than about 3 readings per second you will not need to take into consideration the time it takes for the logger to service the scan The following table and notes provide information on how to calculate the time it takes for the logger to service individual readings and the complete scan in applications where e the scan involves taking readings more frequently than 3 times per second e many channels of widely differing readings that require frequent and unpredictable autoranging are to be logged e many channels require processing and or compression of data prior to storage Time taken servicing a LOG or EVENT
84. e that provide an output voltage which may be either positive or negative with respect to the common mode potential you must assume the lower common mode range figure of 1 05V Small excursions outside the common mode range cause subtle errors which might be difficult to detect Larger excursions cause complete malfunction of the analogue input circuitry Look out for the following sources of common mode voltages e The outputs of bridge sensors have a common mode voltage For typical bridges made up of four equal resistances the common mode voltage is equal to half the excitation voltage The common mode voltage will be a problem if the excitation voltage is too large and referenced to the logger s earth For example gt Bipolar bridges excited by the LFW1 voltage source if it has been set above 2 1V DL2e Hardware Reference Hardware Reference DL2e Hardware Reference Sensors and Input Cards Earth loops and common mode voltages gt Bridge excitation provided by a voltage source external to the logger and powered from the logger s power supply If it is necessary to share the logger s power supply you may need to bias the excitation power supply to bring the sensor output into the logger s common mode range Induced voltages where sensors and connecting leads that are electrically isolated from the logger s earth behave as aerials picking up electrical noise signals Such voltages are high impedance They don
85. e 54 Diagnosing faults If what you type does not appear on the computer screen exactly as keyed in Hardware Reference check that the logger is in echo test mode as described above check that you are not typing too fast the logger responds relatively slowly in echo test mode The table below lists symptoms of possible communication problems with likely causes and their solutions Symptom Nothing that you type appears on the computer screen nor on the logger s display Characters you type appear on the logger s display but not on the computer screen Nonsense characters appear on the logger s display and or computer screen Alternate appearance of a star shaped symbol in the logger s display Cause Transmitted data signals from the computer are failing to reach the logger Data signals from the computer are reaching the logger but data signals from the logger are failing to reach the computer The logger s communication parameter settings baud rate data bits parity don t match the terminal program s serial port settings Logger is no longer in echo test mode When finished Solution Check that the logger is correctly connected to the computer serial port specified in the Communication Options dialogue window Check your cable wiring particularly connections to the logger s RXD and GND 25 pin connector pins 1 3 7 or 9 pin connector pins 2 and 5 Your compu
86. e Reference DL2e Logger Hardware Communication cables Communication cables The construction of communication cables varies depending on the device that is to be connected to the logger Different cables are required for connecting the logger to e computers e printers e modems The logger s RS232 serial port configuration There are two types of RS232 connector fitted to the logger Older loggers are fitted with a 25 pin male D connector on the front panel male connectors have pins female have sockets Newer loggers are fitted with a 9 pin male D connector on the side panel A matching female connector is required for the logger end of the cable Five communication functions are m iM on the logger s D connector Pin no Pin no 25 pin 9 pin a Ground 0 V reference for all other signals Transmitted Data the logger sends data on this ace Received Data the logger receives data on this line Request to Send an output line used by the logger to indicate that it has data available for transmission When the logger is ready to transmit data it puts a positive voltage on this line otherwise it holds it at a negative voltage This signal can be ignored unless you want to use the logger with a Clear to Send an input line which can be used to stop and start data transmission If a negative voltage is applied to this line it causes the logger to halt data transmission Otherwise i e if disconnected or h
87. e errors described above Ls2Win converts these raw data to engineering units and presents readings with a sufficient number of decimal places to represent each resolution step The maximum rounding error that can occur is just less than one resolution step Counter and frequency sensors linear conversion to engineering units Rounding The logger stores readings as a number of counts with large numbers of counts being rounded to the multiples of 8 or 64 Number of counts 0 to 4095 4096 to 32760 ee J 32768 to 65472 Resolution of frequency readings The frequency represented by each stored count and hence the resolution of frequency channels depends on the length of the sampling interval For example Sampling interval Hz Page 148 DL2e Hardware Reference Appendices Appendix B Accuracy of logger readings Linearisation errors Value calculated by the logger Actual input DL2e Hardware Reference The logger calculates engineering unit values from linearisation tables by linear interpolation i e it treats each segment of a linearisation curve as a straight line The error due to this is as illustrated below Engineering units Data point n 1 Linear interpolated segment Data point n Base unit value read by Logger signal Base units Figure B 1 Error due to linear interpolation Once linearised the stored data is rounded to a resolution that depends on the magnitu
88. e gives an absolute worst case accuracy figure which would result if all the error sources conspired to act in the same direction In practice worst case errors of this magnitude are unlikely to occur A more realistic estimate of likely errors can be obtained by calculating the root mean square of independent error contributions i e calculate the square of each error add them up and take the square root Page 144 DL2e Hardware Reference Appendices Appendix B Accuracy of logger readings Analogue accuracy Voltage reading accuracy The logger reads voltage on 4 ranges normally auto ranged n 2 097V The key voltage reading accuracy specifications are given below maximum values with typical figures in brackets Logger 20 C 20 to 60 C Temperature Full scale error 0 07 0 04 0 2 0 1 0 25 02 over 1 year Differential Offset 10uV Bu V 0 02 12u V 0 02 024V RMS Input Impedance approximately 100 MQ Common Mode Range 2V or 1 05V if input is closer to logger QV than input Near the full scale of each range of a recently calibrated logger the maximum error is the Full Scale Error At the lower end of each scale the errors are dominated by the Resolution plus the Differential Offset EXAMPLE DL2e Hardware Reference When reading a 2 Volt input with the logger at 60 C e Maximum error is 2V x 0 2 0 004V 4mV When reading 5mV with the logger at 20 C e
89. e sensor and R2 R3 and R4 are bridge completion resistors If 4 wire sensors are available a 4 wire resistance measurement with resistance offset is easier to implement needing no resistors mounted on the screw terminal block Quarter bridge Quarter bridge is a term commonly used for 4 wire resistance measurements with a resistance offset see Resistance 4 wire on page 106 6 wire bridge In a 6 wire bridge the excitation voltage actually received by the bridge is sensed rather than assumed as being equal to the excitation voltage output by the logger To implement a 6 wire bridge a separate logger channel should be programmed to record the excitation voltage at the bridge and the bridge data corrected after collection to disk file A simpler procedure is to measure the excitation voltage at the sensor manually as described in Conversion to engineering units below Integral excitation Another common form of bridge sensor contains an integral excitation source This type of sensor requires a power supply rather than excitation which may be turned on and off using the logger s relay channels The sensor output is measured on an individual channel as a simple voltage See remarks below about possible common mode problems with this type of sensor Setting up the LFW1 card e Connect one or two ribbon cable s from any terminal group to either or both positions on the card DL2e Hardware Reference Page 109 Sensors and Input C
90. e to be measured across and The cold junction thermistor can be switched to channel 1 See Figure 23 In most cases set the R PRT switch to R Use the PRT position if you require a resistance offset You can compensate for it by entering a zero offset in the logging program Connect one or two ribbon cable s from any terminal group to either or both positions on the card Programming Issues When programming a sensor type or entering measurement details for a lt Custom sensor type gt proceed as follows in the Measurement tab of the Sensor Type or Channel Properties dialog 4 DE 6 Accuracy Select Electrical Measurement Resistance If programming a sensor type also select Connection Requirement 2 wire For Excitation select the largest excitation that can accommodate the range of resistance s that you need to measure but note that 2000 uA excitation current is unsuitable for use with LAC1 30 ch mode Refer also to Selecting a suitable excitation current on page 108 Hint For sensors with linear conversion to engineering units you can compensate for cable resistance and LAC1 30 ch mode internal errors by entering an offset value To determine the offset program the channel s with no offset fit cables to each channel and short out the sensors themselves then READ each channel to obtain the required offset value The logger s resistance measurement accuracy is fully described in A
91. e to contact a local agent distributor then contact Delta T directly Delta T can be contacted via any of the following methods Web Site http www delta t co uk e mail tech support delta t co uk Phone 44 0 1638 742922 Fax 44 0 1638 743155 Post Delta T Devices Ltd 128 Low Road Burwell CAMBS UK CB5 0EJ DL2e Hardware Reference Page 59 Sensors and Input Cards Hardware Reference Overview of electrical measurement techniques Chapter 6 Sensors and Input Cards Overview of electrical measurement techniques Electrical signals can be broadly categorised as analogue or digital Digital signals Digital signals have two valid states with instantaneous in reality very short transitions between them The two states are variously called ON OFF HIGH LOW TRUE FALSE 0 1 Electrically the two digital states are often represented by the presence absence of a voltage or by the open closed state of a switch Both forms are suitable as inputs to the logger Digital signals can convey information in numerous ways The logger has the following functions for interpreting digital signals Digital status Indicates which digital state is present at a point in time EXAMPLE a switch indicating whether a door is open or closed Counter Counts digital pulses continuously and returns the number of accumulated counts While logging counter channels continue to accumulate counts even while the logger is asleep Counte
92. easurements This connection scheme is suitable for general purpose resistance measurement Errors due to cable resistance are not completely eliminated but are smaller than with 2 wire measurements Only one of the sensor connection wires contributes to cable resistance error This return wire can be made of thick low resistance cable and shared between several sensors for economy 3 wire bridge Do not confuse 3 wire resistance with 3 wire bridge measurements Many sensors specified for 3 wire connection for example PT100 platinum resistance thermometers must be measured using the bridge technique This requires an LFW1 card with precision bridge completion resistors Setting up e Set the 15 30 switch to 15 e Connect one ribbon cable only from any terminal group to the position marked differential on the card e Sensor connection the and terminals are wired separately to one end of the pe sensor The other end of the sensor returns to earth using low resistance cable The return can be common to several sensors Programming Issues When programming a sensor type or entering measurement details for a lt Custom sensor type gt proceed as follows in the Measurement tab of the Sensor Type or Channel Properties dialog 1 Inthe Measurement tab select Electrical Measurement Resistance 2 If programming a sensor type also select Connection Requirement 3 wire 3 For Excitation select the
93. ech battery pack G General Status Report H Half bridge Handshaking heating effect of excitation current high frequencies counting at Humidity Page 158 62 62 89 48 143 35 37 38 30 12 22 24 63 12 22 24 132 129 60 9 10 23 23 10 27 28 24 108 75 43 129 129 55 30 23 31 34 30 60 115 148 22 109 89 33 12 13 13 33 13 23 13 18 13 28 29 13 21 48 19 109 33 36 108 117 Index protection against 55 Humidity indicator 55 I IC installing 49 Immediate start 27 28 Impedance input 86 89 Inactive source 34 Induced electrical noise 62 Input impedance 86 89 Input card 67 AC ACD1 73 ACD1 61 analogue 61 installing 67 LAC1 61 LFW1 61 standard analogue LAC1 69 Input protection card LPR1V 61 80 LAC1 70 LFW1 75 Installation IC s 49 in the field 55 Intermittent logging 126 INTERNAL 41 INTL 41 J J K T type thermocouples 134 K K 21 Keypad functions 12 13 Keypad main menu 12 L LAC1 61 69 30 ch mode 63 LBK1 46 storage 57 Leap year 18 Leap years 20 LFW1 61 Linearisation errors 149 Lithium cell 42 57 LOG 9 10 24 26 28 Logger status 19 Logging 10 27 intermittent 126 speed 150 started 20 stopped 21 stopping 29 logging program 20 Logic level signals 120 LPR1 attenuator card 61 80 LPR1V input protection card 61 80 DL2e Hardware Reference Index M Main circuit board layout Main menu keypad Ma
94. ecommended for accurate RTD measurements Using PT100 And other RTDs with the DL2e logger Sensor connections e A rough temperature measurement can be obtained using 2 3 and 4 wire connection to LACI in 15 ch mode or LFW1 without resistance offset using sensor code PRT These measurements will be inaccurate as seen below Do not confuse the logger s 3 wire resistance measurements with 3 wire sensors intended for 3 wire bridge connection e The recommended technique is to use the LFW1 with offset The factory set default is for PT100 measurements centred on 20 C Programming the logger There are three LFW1 Input card type options in the DL2 Program Editor corresponding to the three possible combinations of the R PRT switch and the L1 jumper R4 or 20 C on the LFW board PT100 using simple resistance measurement If the LFW1 card has the R PRT switch set to R signifying no offset then select Input card type LFW1 no offset in the DL2 Program Editor For the Sensor Type select the Platinum Resistance Thermometer type Pt100 simple resistance from the sensor library sensor code PRT PT100 centred on 20 C using LFW1 with offset If the LFW1 input card has the R PRT switch set to PRT and jumper L1 in the 20 C position then select Input card type LFW1 20C PRT Offset in the DL2 Program Editor DL2e Hardware Reference Page 131 Sensors and Input Cards Hardware Reference Platinum Resistance Thermometer
95. ection consider differential connection with earthed sensor or bias resistors see Figure 19 Sensor connections differential voltage e The logger s input impedance is only specified for the logger when awake and may drop significantly when the logger sleeps If using a sensor with a high source impedance check that it can respond quickly enough within 250ms to the change in the logger s input impedance as it wakes Page 86 DL2e Hardware Reference Hardware Reference Accuracy See also DL2e Hardware Reference Sensors and Input Cards Voltage single ended The logger s basic voltage measurement accuracy and other factors affecting accuracy are described in Appendices A and B Note that the LAC in 30 channel mode has an offset error typically in the region of 20uV in addition to the differential offset quoted in the specification LACI card on page 69 LFW1 card on page 75 Discussion of single ended versus differential connections page 61 Earth loops and common mode voltages on page 95 Voltage measurements up to 50V on page 92 Page 87 Sensors and Input Cards Hardware Reference Voltage single ended LAU I 30 channel mode 15730 Suitch set to 30 LAC 15 channel mode 15730 switch set to 15 LFW Figure 18 Sensor connections voltage single ended Page 88 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Voltage differential Voltage
96. ed every year to guarantee conformance to specifications For more information please contact your local Delta T representative Page 57 DL2e Logger Hardware Hardware Reference Warranty and Service Warranty and Service Terms and Conditions of Sale Our Conditions of Sale ref COND 1 00 set out Delta T s legal obligations on these matters The following paragraphs summarise Delta T s position but reference should always be made to the exact terms of our Conditions of Sale which will prevail over the following explanation Delta T warrants that the goods will be free from defects arising out of the materials used or poor workmanship for a period of twelve months from the date of delivery Delta T shall be under no liability in respect of any defect arising from fair wear and tear and the warranty does not cover damage through misuse or inexpert servicing or other circumstances beyond our control If the buyer experiences problems with the goods they shall notify Delta T or Delta T s local agent as soon as they become aware of such problem Delta T may rectify the problem by supplying faulty parts free of charge or by repairing the goods free of charge at Delta T s premises in the UK during the warranty period If Delta T requires that goods under warranty be returned to them from overseas for repair Delta T shall not be liable for the cost of carriage or for customs clearance in respect of such goods However we much p
97. eld at a positive voltage the logger will continue to transmit any data that has been requested either by a computer or if PRINT has been used DL2e Hardware Reference Page 51 DL2e Logger Hardware Hardware Reference Communication cables Computer cables IBM compatible computers are almost universally fitted with one of two styles of serial port connector 25 pin and 9 pin male D connectors You will require a matching female D connector The pin connections required for both styles of cable are shown in the table below Logger PC Pin no Pinno Signal Signal Pin no Pin no 25 pin 9 pin 9 pin 25 pin If your computer is fitted with a different style of connector refer to its user manual to determine which signals are carried by which pins Remarks The flow of information between the computer and logger is controlled by the software The CTS line should not be connected to the computer At the computer end you may find it necessary to fit wire links to join CTS RTS and DSR DCD DTR If you do so you might find it convenient to make the cable symmetrical and fit the same links at the logger end not shown in the table This won t affect logger operation Cables for printers Printers are not generally able to print data as fast as the logger can send it To prevent loss of data your printer should have a control line which should supply a positive voltage when the printer is ready to accept data an
98. entally selected Page 44 DL2e Hardware Reference Hardware Reference DL2e Logger Hardware Power supplies DL2e LOGGER POWER SUPPLY 0V SCHEMATIC TO CIRCUITS AND VOLTAGE SENSING RELAY CHANNELS 63 64 INTFRNAI BAI IERY sm a ne ny m le g G AE g NON RESFARG AELE ny EXTERNAL POWER SOCKET NTFRNAI FARTH CONNECT CN DIGITAL ES ped EARTH 0V l p ap COUNTER CHANNELS I ene AND ANY CTHER ANALOGUE NPUT SARDE i EARTH GV INPUT o CHANNELS 1 60 Figure 3 power supply OV schematic DL2e Hardware Reference Page 45 DL2e Logger Hardware Hardware Reference Rechargeable battery pack type LBK1 Rechargeable battery pack type LBK1 The battery pack contains a rechargeable sealed lead acid battery in a weatherproof housing which mounts externally onto the logger enclosure Fully charged it has a capacity approximately 50 greater than the normal internal set of 6 alkaline AA cells and can power the logger for up to 36 hours of communicating or keypad operation or for approximately 750 000 readings Smm allen rs M6x6 hex socket cap screw gt 8 threaded insert gt knurled thumbscrew gt rubber gasket external Ff power battery unit supply 1A fuse socket socket for power supply or charging lead power supply oe eae oN red to charger charging lead Sy ee fs black to charger Figure 4 Fitting the external b
99. et aside for event triggered data that is data stored when events are detected on event trigger channels if channels 61 and 62 are programmed as event trigger channels These areas of memory are referred to as TIMED RAM TRIG 61 RAM and TRIG 62 RAM or datasets respectively and their status is reported separately Note that e IK is 1024 bytes and that each reading requires 2 bytes of memory e All TIMED RAM is available for data for example 128K of TIMED RAM is 131072 bytes and can store 65536 readings e Event triggered data is stored with an additional 7 bytes of date and time information for each repetition of an event triggered sequence and the number of event triggered data that can be stored in a given amount of memory is reduced accordingly e DL2 Control Panel also reports the number of data since data was last retrieved These readings can be retrieved from the logger separately See the on line Help for details e Auto wrap mode allows the logger to continue logging timed data when TIMED RAM fills up by overwriting old data See the on line Help for details Auto wrap mode status is only reported by Ls2Win See also the on line help for the DL2 Control Panel program Using Ls2Win The DL2 Control Panel displays logger status information See also its on line Help and Lesson 2 in Getting Started Using the keypad display At the Keypad main menu or while the logger is asleep press WAKE The status report consis
100. ferences is low typically 30 to 40 uV per C The logger s voltage offset can therefore cause an error amounting to a significant fraction of a C Accuracy DL2e Hardware Reference Typical errors of common thermocouples measuring 20 C to 60 C Thermocouple Error Class 1 types J K Class 1 type T Using thermocouples with the DL2e logger Setting up Sensor connections Single ended voltage connection is suitable for many applications but bear in mind the following points e 6A large offset typically 20u V is possible on LAC voltage measurements in 30 ch mode corresponding to errors of 0 5 C or more Use LAC1 in 15 ch mode if this is unacceptable e Beware of creating earth loops In particular avoid bare sensors in contact with metalwork or conducting substances such as water If unavoidable use fully floating connections but beware of common mode problems sees Earth loops on page 95 and Common mode voltages on page 96 e Inelectrically noisy conditions noise rejection can be achieved by using screened thermocouple cable and earthing it to the logger or by earthing the sensor or fitting bias resistors see Voltage differential on page 89 for details Page 133 Sensors and Input Cards Hardware Reference Thermocouples Cold junction compensation e Use the on board cold junction thermistor switched into channel 1 e LACI should be set to 15 ch mode for better accuracy but can be set t
101. g 36 Continuous data collection as a backup 37 Erasing data from the logger s memory 37 Using Ls2Win 37 Using the keypad display 37 Chapter 5 DL2e Logger Hardware ________ 39 Power supplies 41 Internal battery operation 41 Lithium cell 42 External power supplies 43 WARNINGS 44 Rechargeable battery pack type LBK1 46 Assembling the battery pack 47 Fitting the battery pack to the logger 47 Recharging 47 IMPORTANT WARNINGS 48 Overload protection 48 Electrical mains environment 48 Display contrast 49 Installing IC s 49 Communication parameters 50 Communication cables 51 The logger s RS232 serial port configuration 51 Computer cables 52 Cables for printers 52 Testing communication 53 Terminal mode 53 Echo test 53 Diagnosing faults 54 Other causes of communication problems 54 Field installation 55 Temperature 55 Moisture 55 Maintenance Storage Repairs and Recalibration 57 Maintenance 57 Storage 57 Repairs 57 Recalibration service 57 Warranty and Service 58 Terms and Conditions of Sale 58 Service and Spares 58 Technical Support 59 Chapter 6 Sensors and Input Cards _______ 60 Overview of electrical measurement techniques 60 Digital signals 60 Analogue signals 60 Analogue input cards 6l Supplementary cards 6l Voltage measurements 6l Current measurement 62 Page iv DL2e Hardware Reference Contents
102. ge 121 Sensors and Input Cards Hardware Reference Relay channels Relay protection Fuses and varistors protect the relay contacts roma y closed NC rormaly ogn NO CONNECTIONS TQ TERMINAL BLOCK rolery cor acis 762 5 carmen 6867 fuse DL2e RELAY CONIAC IS SCHEMATIC Figure 34 DL2e relay circuit Varistor The varistor across the relay contacts will limit the voltage of either polarity and prevent arcing The working voltage of the varistor must not be exceeded during normal use A varistor is connected across each of the relay contacts Varistor type Type RS stock No working V clamp V V22ZA1 649 122 18Vdc 47Vdc Fuses Fuses limit the maximum current through the relay contacts preventing welding or other contact damage The fuses fitted are European TRS rated at 1A Fuse type Type Farnell stock No TR5 1A Quickblow fuse 151 105 Setting up Connections e The NO terminal is the one that is connected when the relay is nominally ON Use this terminal for normal relay operation e The NC terminal is connected when the relay is nominally OFF Use this terminal if you want a control output relay to switch a device on when an input falls below the threshold value Page 122 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Relay channels To draw power from the logger s internal power supply Fit jumper s in the appropriate position s on the rear of the terminal pane
103. gger channel The logger starts logging 1s to 2s after detection of the trigger event just as for an immediate start Data trigger channel The logger records the time when it starts to record event triggered data rather than the time of detection of the event trigger The size of the delay depends on whether or not the logger is already awake and whether or not the logger is already busy with a LOG DL2e Hardware Reference Page 119 Sensors and Input Cards Hardware Reference Digital inputs and Counter Card type DLC1 Providing additional digital status channels Analogue input channels on LAC1 or LFW1 cards can be used to record digital status Voltage free switching e Fit a resistor in parallel with the switch and set up a channel for resistance measurement gt With the switch open the logger measures the resistor gt With the switch closed the resistor is shorted out and the logger measures OQ Logic level signals e Fit divider resistors to measure logic level voltages as described in Voltage up to 50V DC on page 92 e Program the logger to take fixed range readings If required you can select conversion factors so that the logger returns values close to 0 and 1 Page 120 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Relay channels Relay channels The logger s relay channels 63 and 64 can be used for powering sensors or other devices either from the logger s own batteries or p
104. gue techniques 4 wire resistance and bridge measurements as well as for general purpose voltage current and resistance measurements Supplementary cards LPR1 LPR1V The supplementary cards types LPR1 and LPRLV are fitted in series with analogue input cards and don t themselves provide additional channels The LPR1V is an input protection card which provides additional protection for LAC1 ACD1 and LFW1 cards against overload voltages accidentally applied to input channels the input channels are already protected against small overload voltages ACS1 AC Excitation Source card intended primarily for use with analogue input card type ACD1 Provides a 2 0V square wave excitation signal for up to 60 AC resistance sensors such as gypsum block or granular matrix soil moisture sensors Voltage measurements LAC1 LFW1 and ACDI cards can be used to measure DC voltages in the range of 2V ACDI can also measure voltages in the range 0 2V ac rms Voltages up to 50V can be measured by fitting resistors in a divider configuration Divider resistors can be fitted to the logger s screw terminals Alternatively if using a LAC1 or ACD1 the resistors can be mounted on an LPR1 or LPR1V card Single ended and differential sensor connections Voltage connections to either card can be single ended or differential except that in 30 ch mode the LAC1 accepts only single ended connections DL2e Hardware Reference Page 61
105. h higher voltages The shorter the spike the higher the voltage Page 70 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Analogue Input Card type LAC1 Additional input protection can be obtained by fitting an input protection card LPR1V in series with the LAC1 SS Sher meds only aeea ribbon cable from ribbon cable from terminal group terminal group 16 30 or 46 60 1 15 or 46 60 OUUYoUCcudO 30 channel JeuUeYyo St ribbon cable from any terminal group 15 ch mode only 15 30 switch Figure 6 LAC analogue input card DL2e Hardware Reference Page 71 Sensors and Input Cards Hardware Reference Analogue Input Card type LAC1 30 channel nial 6V 5vu lexc or 5n typical typical values XX typical values matched to 10R across channels compensated in autozero 6y 5mA typical 6y typical values 6v x typical values 6V Figure 7 LAC1 input stage schematic diagrams Page 72 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Analogue Input Card type ACD1 Analogue Input Card type ACD1 The AC Card type ACD1 is a general purpose analogue input card It has the capability to measure 15 differential input channels which may be dc voltages in the range 2V ac voltages in the range 2V rms and resistances Accuracy for dc voltage and resistance readings is the same as that for the LACI1 in 15 channel mode
106. he logger s voltage measurement accuracy is fully described in Appendices A and B Divider resistors contribute the following additional errors If using a calculated value for the conversion factor add the tolerances of each resistor e g a pair of 0 1 resistors contribute a maximum error of 0 2 You may also need to take contact resistances into account The temperature coefficient tempco of each resistor has to be added if the logger is to operate over an extended temperature range e g if using a pair of 15ppm C resistors and operating over 20 C to 60 C the maximum tempco error contribution is 2x 40 C x 15 ppm 1200 ppm 0 12 about a 20 C base Channels connected via an LPR1 or LPR1V card with uncut tracks and no resistors fitted behave as normal channels Remember to repair cut tracks if reconfiguring the channel for another purpose without shunt or divider resistors Analogue Input Card type LAC1 on page 69 4 Wire Card type LFW 1 on page 75 LPRI card Capabilities on page 80 Discussion of single ended versus differential connections Voltage measurements on page 61 Earth loops and common mode voltages on page 95 Single ended page 86 and differential page 89 sensor connections Page 93 Sensors and Input Cards Hardware Reference Valtaro nn ta KAV AC Leis with Gl l VM 15 730 Switch TOP SIDE set to 30 Resistors in place Cut Track link fA
107. he logger stops logging data of that data type but note that overwrite mode allows the logger to continue logging timed data Using Ls2Win Click Stop in the Logger panel of DL2 Control Panel Using the keypad display At the Keypad main menu press START lt START gt A message indicates that the logger is already logging If this message does not appear then this procedure will start logging instead of stopping it see the previous section l already logging to STOP If the logger contains stored data and is also programmed with a password you are prompted to enter it password Press START again to confirm that you want to stop logging Press any other key if you decide not to stop logging l lt START gt confirms other keys abort Logging stops after confirmation and the logger returns to the main menu logging stopped Using the internal STOP button DL2e Hardware Reference Open the logger s lid and hold down the STOP button see Figure 2 Main circuit board layout While the STOP button is held down do one of the following e Ifthe logger is asleep wake the logger by pressing WAKE e Ifthe logger is already awake press the RESET button see Figure 2 Main circuit board layout Logging will also stop if the STOP button is held down when the logger wakes of its own accord in order to log data This method of stopping logging is not protected by passwords Page 29 Col
108. he spike the higher the voltage Additional input protection can be obtained by fitting an input protection card LPR1V in series with the LFW1 but shunt and divider resistors must not be fitted to the LPRIV Page 75 Sensors and Input Cards Hardware Reference 4 Wire Card type LFW1 Setting up Ribbon cables Any terminal group can be connected to either A or B ribbon connector blocks Cold junction thermistor The LFW1 card cannot be used to read the cold junction thermistor If using the LFW1 card with terminal group 1 15 ensure that both halves of the cold junction thermistor switch are in the OFF position LFW1 connector blocks Each LFW1 channel has 5 screw terminal connections for Negative differential voltage input Positive differential voltage input Earth excitation return Current source configurable to 2 20 200 or 2000 mA Voltage source adjustable 1 4 V Use the LFW1 label set to label the terminal blocks E at Voltage measurement Set the R PRT switch to R i e no resistance offset if you require differential voltage measurements with significant common mode voltages e g bridge measurements If in doubt avoid mixing differential voltage measurements and offset resistance measurements on the same LFW1 card Single ended voltage measurements are not affected by the setting of the R PRT switch A resistance offset degrades the logger s ability to reject common mode noise Resis
109. ice also performs bytecount and checksum calculations you can compare the results to verify the integrity of the data you have collected Handshaking Your equipment may be unable to store data as fast as the logger transmits it especially BIN format data To avoid losing data your equipment should have a facility for handshaking This controls the data output from the logger to a rate the equipment can accept so that none is lost Refer to the equipment s user manual for details of how to implement its handshaking facility The logger can respond to two forms of handshaking hardware handshaking and software or XON XOFF handshaking Hardware handshaking is only suitable for PRN format data output Follow the instructions in Communication cables page Communication cables on page 51 for constructing a printer cable XON XOFF handshaking is only available when the logger is transmitting BIN format data In XON XOFF handshaking the receiving equipment transmits an XOFF character ASCII code 19 to the logger when a pause in data transmission is required and an XON character ASCII code 17 when ready for data transmission to resume Since the XON and XOFF information is received in the same way as any other incoming data a simple 3 wire cable transmitted data received data and OV is sufficient to implement XON XOFF handshaking See Communication cables on page 51 for details of the logger s RS232 connector DL2e Hardware
110. ifferential offset Setting up LAC1 30 ch mode e Set the 15 30 switch to 30 e Install ribbon cable s from one or two terminal groups to the corresponding s e 30 channel position s on the card The terminal of each channel is linked to earth on the card There is no need for an external link LAC1 15 ch mode amp ACD1 e Set the 15 30 switch to 15 e Install one ribbon cable only from any terminal group to the differential position on the card dl e Fit link L1 between and on screw terminal block ACD1 e Set as LAC1 15 ch mode LFW1 e Install one or two ribbon cable s from any terminal group s to either or both positions on the card iis e Fit link L2 between and on the screw terminal block Programming Issues When programming a sensor type or entering measurement details for a lt Custom sensor type gt proceed as follows in the Measurement tab of the Sensor Type or Channel Properties dialog 1 Select Electrical Measurement DC Voltage 2 If programming a sensor type select Connection Requirement Single ended Remarks e Beware creating earth loops particularly if you have gt electrically interconnected sensors gt sensors operating on a mains power supply or sharing the logger s power supply The alternative is to use fully floating differential connections see Voltage differential on page 89 e For better common mode noise rej
111. in a plastic bag with desiccant and a seal at the sensor cable exit High resistance and high impedance voltage measurements are particularly sensitive to the effects of moisture films on the logger s terminals As an additional precaution against the effects of moisture or corrosive atmospheres spray the terminals and connector blocks with water repellent contact oil such as RS Components product stock number 567 610 Avoid petroleum distillate sprays These contain solvents that affect the rubber grips and labels on the terminals Regenerating desiccant Place the bags in an oven at 110 120 C for 7 hours approx to regenerate expired desiccant Exceeding this temperature may cause the glue sealing some types of desiccant package to melt When the water has been driven off remove the capsules or bags and seal them in a plastic bag to cool down until they are ready for use Page 56 DL2e Hardware Reference Hardware Reference DL2e Logger Hardware Maintenance Storage Repairs and Recalibration Maintenance Storage Repairs and Recalibration Maintenance Storage To keep the logger functioning properly e Keep the batteries and desiccant fresh e Avoid use beyond 20 C to 60 C e Avoid storage beyond 30 C to 60 C e Don t leave the logger in direct strong sunlight If the logger is put away for storage for a long period of time remove the main battery and the lithium cell and keep the logger in a dry place w
112. inal block Select values in the range 100Q to 10kQ such that R3 R4 R1 R2 at the point where the bridge output is zero 3 wire bridge e Mount resistors R2 R3 R4 on the logger s screw terminal block Select values equal to R1 For a voltage excited bridge the I terminal can be used as a spare terminal for mounting R2 For both half and 3 wire bridges the resistance of the two current carrying wires Rx and Ry appear in opposite halves of the bridge Their effects cancel out provided that they have the same resistance It is important that these two wires are of the same length and type Sharing bridge completion resistors e R3 and R4 can be shared between up to 6 similar half or 3 wire bridges in any terminal group as illustrated in Figure 27 Sensor connections bridge measurements Calibration Bridges can be calibrated by applying known stimuli to the sensor and noting the logger s resulting readings This gives calibration data that can be used for configuring the logger either by deriving a conversion factor and zero offset or entering a linearisation table Programming Issues When programming a sensor type or entering measurement details for a lt Custom sensor type gt proceed as follows in the Measurement tab of the Sensor Type or Channel Properties dialog 1 Voltage excited bridge Page 110 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Bridge measurements a Select Electric
113. ines the format the logger uses for displaying the date 50 60 switch European day month dd mm American month day mm dd The factory setting is ON 50 Hz mains European date format Page 48 DL2e Hardware Reference Hardware Reference DL2e Logger Hardware Display contrast Display contrast Wake the logger and turn the contrast adjustment trimmer see Figure 2 Main circuit board layout to obtain good display contrast Installing IC s You may need to install IC s in the logger s main board e additional memory RAM IC s e PROM you will need to replace this if you want to install an updated version of the logger s internal control program Proceed as follows Take anti static precautions Observe normal procedures for handling CMOS devices in order to prevent static damage e Disconnect the logger from all external devices and power supplies Ensure that no important data are stored in the logger then remove the internal batteries and the lithium cell e Keep the IC s in conductive holders or foam until insertion Earth yourself to the logger s safety earth terminal see Fig 12 2 and the IC holder by touching them simultaneously Removing IC s If an IC needs to be removed gently prise it out with a small screwdriver alternately inserting the flat blade under each end of the IC Take care not to bend the legs IC position and orientation The positions of memory and PROM IC s are
114. intenance Malfunction deleting reports sensor warning relay warning relay resetting Maximum value in data file header Memory check filled full IC installing status Minimum value in data file header Moisture effect on measurement accuracy protection against N Noise induced electrical Noisy electrical environment Number of data O o s limits Offset applied to resistance measurements On board digital channel relay channel Outside limit Outside table Over range Over run Overwrite mode Parity Password Platinum resistance thermometer 3 wire 4 wire Potentiometric measurement power supply external Power supply backup cable external failure selector switch power supply OV schematic Powering sensors Preset time start DL2e Hardware Reference 40 12 57 26 25 24 25 26 26 15 26 25 49 21 26 55 55 62 25 62 89 34 26 106 115 121 25 25 25 11 24 26 118 15 21 33 50 17 106 131 111 106 63 75 113 19 41 42 43 43 43 41 45 24 64 121 123 27 PRINT PRINT function Printer checking operation outputting data directly to Priority tasks conflicting PROM installing version PT100 3 wire 4 wire Pulse count Quarter bridge R PRT switch RAM check chip installing RAM STATUS Reachargeable battery pack storage READ function Recalibration Rechargeable battery pack Rechargeable battery pack LBK1 sspecifications Chan
115. ion resistors R3 RH Figure 27 Sensor connections bridge measurements Page 112 DL2e Hardware Reference Hardware Reference Potentiometer Sensors and Input Cards Potentiometer The LFW1 card is required for potentiometric measurements A potentiometer consists of a wiper that moves along a coil of resistance wire Precision potentiometers are used in sensors for displacement direction force and other movement sensors The position of the wiper can be determined by a simple resistance measurement but a direct potentiometric measurement has the advantage of being independent of the absolute value of the potentiometer s resistance Setting up the LFW1 card Connect one or two ribbon cables from any terminal group to either or both positions on the card An excitation voltage source is automatically applied to the V terminal of each of the 6 channels in a terminal group whenever any channel in the terminal group is being read gt Youcan adjust the voltage source for each of the two channel groups on the LFW1 if required see Voltage sources on page 78 gt Ensure the current limiting LED indicator does not light This indicates current limiting and that the voltage source output is reduced Wind vanes and other rotary potentiometric transducers have a small gap at the point where the two ends of the potentiometer meet to prevent the wiper simultaneously contacting windings at both ends of the potentiometer To
116. ischarging it unnecessarily Lithium cells have a shelf life of 10 years and don t need routine replacement It is not possible to determine the remaining life of the lithium cell Replace the lithium cell if you know it is partially discharged for example if the logger s battery voltage has dropped below 3V for an extended period of time To replace the lithium cell If you have important data stored in the logger s memory ensure that the logger is fitted with a good set of batteries or connected to a power supply Otherwise the stored data will be lost when you remove the lithium cell Any 3 Volt 20 mm diameter lithium cell is suitable DL2e Hardware Reference Hardware Reference DL2e Logger Hardware Power supplies Slide the lithium cell out of its holder and slide in the replacement ve terminal uppermost Ensure that the spring contact grips the cell firmly Handling Lithium cells When handling the lithium cell take care not to touch the insulator between the two halves of the case The deposit left by a fingerprint conducts enough electricity to shorten the life of the cell significantly External power supplies The logger requires a power supply capable of providing 70 mA plus any current drawn from a single LFW1 voltage source max 60mA at 7 to 15 V DC i e 130mA total The supply voltage does not need to be regulated Suitable power supplies include e 12V rechargeable batteries such as a car bat
117. ithin 30 C to 60 C When the logger is again required for use replace the batteries and cold boot the logger see Resetting the Logger XXXX TO DO Then program the logger for your requirements Storing rechargeable battery packs LBK1 Battery packs may be stored at 5 to 40 C They have a storage life in excess of 10 years if kept fully charged The interval between recharging the stored battery packs depends on storage temperature Storage temp C Interval between recharging Repairs 10 months 4 months The only repair recommended for users to carry out is the replacement of input protection components on LAC and LFW cards Spares kits are available from Delta T In the event of a logger problem that you can t solve please contact your local Delta T representative if you have one or Delta T Devices directly It will be useful if you can provide the following information e the serial numbers of the logger and any input card s e the logger s PROM version found on the software General status report e the version of computer software you are using Recalibration service DL2e Hardware Reference In our experience the DL2e logger s calibration is typically much more stable than the worst case figures quoted in the specification A calibration service is available if you are concerned about the logger s long term accuracy See Service and Spares on page 58 The DL2e logger should be recalibrat
118. ity but their voltage then falls rapidly to its previous level when the logger is awake Page 19 Interrogating the DL2e logger Hardware Reference Logger status The battery life is calculated on the basis of a linear interpolation between 7V 0 left and 8 5V 99 left and applies to alkaline cells only A battery voltage in excess of 10V is reported as gt 10V and voltages in excess of 8 5V are reported as 99 left Battery Voltage 85V 7 0V Estimated remaining battery life 100 Figure 1 Battery life interpolation Date and time The formatting of the date is linked to the setting of the 50 60 switch see Figure 2 Main circuit board layout e 50 gives European date formatting i e day month e 60 gives American date formatting i e month day Leap years The logger does not keep track of years and cannot identify leap years February is always assumed to have 28 days In a leap year you must re set the correct date manually after 29th February Program or configuration name This is the name of the file containing the logging instructions that you download from the PC to the logging program that is installed in the logger and which tells it when to log which channels to log how to record results and so on The Front Panel display calls this the configuration abbreviated to config n In Ls2Win call this the logging program Logging started Shows the date and time when a command
119. ity settings not matched incorrect e g italics or nonsense characters Several lines of correctly formatted Incorrect wiring of handshake line in cable printout followed by missing data or wrong type of handshake set up in printer Using the keypad display At the Keypad main menu press PRINT In the menus that follow use and Tto toggle between the options and press PRINT to accept the option displayed use lt UP gt lt DOWN gt amp lt PRINT gt Select PRINT and press PRINT to accept PRINT or ERASE PRINT Select TIMED TRIG 61 or TRIG 62 as required and press PRINT to accept l DATA TYPE TIMED The message inactive source indicates that the logger is not programmed to record the type of data you have selected inactive source Select PRN format The alternative BIN format is unsuitable for printing but you might choose it if using an alternative data collection device see Using other data collection devices on page 36 Select a date and time for the first logged data that you want to have output data starting 11 07 15 46 03 Specify the number of readings to be output If there are less than 1K 1024 readings stored all readings is the only option Otherwise you can choose a number of K readings If you want to auto print select all readings DL2e Hardware Reference Hardware Reference Collecting and Erasing Logged Data Outputting data directly to a printer
120. l Otherwise to avoid any risk of shorting out the logger s power supply ensure that they are removed see Figure 34 DL2e relay circuit Use the channel 61 and 62 terminals for power supply returns The other earth terminals on the terminal panel are intended for earthing analogue sensors WARNING Do not use one of these as a power supply return it can cause substantial analogue errors Note that the jumpers connect the logger s power supply to the relay common terminals You can use these terminals for a permanent power connection Checking relay operation READ a relay channel to make it toggle between ON and OFF at 2s intervals You can freeze the relay state by moving on to READ another channel press 6 or T To check operation of sensors that need to be powered by a warm up relay gt READ the warm up relay channel gt freeze the relay in the ON state then gt READ the warmed up channel See also Exercising relay channels on page 24 Programming Issues Using on board relay channels 63 64 In DL2 Program Editor Input Card Type for channel group is automatically set to On board relay channels The Channel Properties dialog for these channels contains a Relay Channel tab Select a relay channel function Warmup Control Output or Malfunciton Warning for these channels and provide any further information that is required in the other tabs of the Channel Properties dialog Remarks If powering
121. l groups fitted in Enables AC excited resistance measurements series with 1 4 ACD1 s by ACD1 On board digital channels 61 62 COUNTER channels FREQUENCY DIGITAL STATUS EVENT TRIGGER On board relay channels 63 64 Change over relays can be programmed for channels warm up control output malfunction warning ch 64 onl DL2e Hardware Reference Page 65 Sensors and Input Cards Hardware Reference Overview of electrical measurement techniques Summary of connections for analogue measurements Recommended cards and sensor connections for analogue measurement applications Card s amp sensor Comments connections VOLTAGE low level dc thermocouples LAC1 15 ch ACD1 LFW 1 single ended general purpose dc powered LAC 15 ch or 30 ch LAC 30 ch may introduce an offset voltage transducers ACD1 LFW1 single error typically 20u V and is not measurements solarimeters ended recommended for low level signals dc voltages long unscreened LAC 15 ch ACD1 Beware of introducing earth loops susceptible to leads LFW1 differential with electrical noise close to switch gear earthed sensor or bias or power cables resistors with existing sensors in contact LAC1 15 ch ACD1 connection to the with metalwork LFW1 fully floating logger s earth interconnected differential power supplies signals in the range vehicle electrical divider resistors fitted Divided voltage measured using LAC1 2 to 50V supply to LPR1 or LPR
122. l manuals e DL2e Technical Reference manual consisting solely of printed circuit board schematics for the various cards and accessories e DL2e Programmers Guide This contains terse information for programmers about communicating with the logger It is provided on your installation disk as a text file Page 8 DL2e Hardware Reference Hardware Reference About the DL2e Logger Waking and sleeping Chapter 1 About the DL2e Logger The DL2e logger unit contains all the hardware required for capturing and storing data from a wide variety of different types of sensor under most environmental conditions It runs an internal logging program that is set up by the user and tells the logger how and when to acquire data The logger s front panel keypad and display gives control over the essential features which are needed for field operation away from a computer such as starting and stopping the logger displaying current readings providing status reports and outputting logged data to a local printer or intermediate collection device The Windows software Ls2Win also provides control over all the features available from the front panel keypad It also is used to program the logger This involves choosing the number of channels to be logged the types of sensor and appropriate data conversions the rate at which each channel is to be logged and action to be taken on out of limits conditions It also provides a range of other features tha
123. largest excitation that can accommodate the range of resistance s that you need to measure but note that 2000 uA excitation current is unsuitable for use with LACI 30 ch mode Refer also to Selecting a suitable excitation current on page 108 4 Hint for sensors with linear conversion to engineering units you can compensate for cable resistance by entering an offset value To determine the offset program the channel s with no offset fit cables to each channel and short out the sensors themselves then READ each channel to obtain the required offset value Accuracy The logger s resistance measurement accuracy is fully described in Appendices A and B The only cable resistance included in the resistance measured by the logger is that of the earth return lead See also Resistance 2 wire on page 101 Resistance 4 wire on page 106 Page 104 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Resistance 3 wire Cold junction thermistor switch single channel multiple channels sharing common 1530 switch earth set to 15 return Figure 25 Sensor connections 3 wire resistance DL2e Hardware Reference Page 105 Sensors and Input Cards Resistance 4 wire Hardware Reference Resistance 4 wire The LFW1 card is required for 4 wire resistance measurements 4 wire connection virtually eliminates cable resistance errors and is suitable for precision resistance measurements p
124. lecting and Erasing Logged Data Hardware Reference Data collection options Chapter 4 Collecting and Erasing Logged Data Data can be collected from the logger at any time during logging There is no need to stop logging Data output from the logger can be controlled either from the logger s keypad or from your PC Data that you have collected can be erased from the logger s memory to create space for more data By repeatedly collecting and erasing data you can acquire as much data as you like regardless of the logger s memory capacity without interrupting logging You can collect data from the logger in the following ways e Printing out data directly from the logger using a printer e Using the Dataset Panel in the PC s DL2 Control Panel to collect data to a computer file Data files can be imported in to Microsoft Excel directly using Dataset Import Wizard or converted to comma separated ASCII dat format files which are suitable for importing into other data processing programs e Using the Data Import Wizard to import data directly into a Microsoft Excel Spreadsheet e Outputting data to an intermediate data collection device and subsequently transferring to a computer for further processing Suitable devices may be stand alone disks cassette drives solid state data collection terminals or simple computers that are unable to run Ls2Win Regardless of the technique used you will have to specify the format quantity
125. lows in the Measurement tab of the Sensor Type or Channel Properties dialog 1 Select Electrical Measurement DC Voltage 2 If programming a sensor type also select Connection Requirement Differential low CM if the sensor output has a negligible common mode for example a sensor powered from the logger s power supply or Differential high CM if the sensor output has a significant common mode The latter setting will exclude the sensor type from being programmed for a LFW1 card set up to provide a resistance offset where common mode can introduce significant reading errors Remarks The logger s input impedance is only specified for the logger when awake and may drop significantly when the logger sleeps If using a sensor with a high source impedance check that it can respond quickly enough within 250ms to the change in the logger s input impedance as it wakes DL2e Hardware Reference Page 89 Sensors and Input Cards Hardware Reference Voltage differential Accuracy The logger s voltage measurement accuracy is described in Appendices A amp B See also e LACI card on page 69 LFW1 card on page 75 e Discussion of single ended versus differential connections Voltage measurements on page 61 e Earth loops and common mode voltages on page 95 e Single ended sensor connections on page 86 e Voltage measurements up to 50V on page 92 Page 90 DL2e Hardware Reference Hardware Refe
126. malfunction reports also resets the malfunction warning relay to OFF if programmed Any flagged data stored in the logger s memory remain flagged Using Ls2Win The DL2 Control Panel displays error status information in the Errors panel See also its on line Help Using the keypad display Displaying malfunction reports Press the WAKE key to wake the logger BATTERY FAILURE MEMORY FILLED and sensor malfunction reports are then displayed after the logger status report To end malfunction reports at any time press any key on the logger s keypad To delete malfunction reports After displaying the malfunction reports the logger offers the option of deleting them to delete report_ Press WAKE to delete the malfunction reports or any other key if you want to retain them in the logger s memory lt WAKE gt confirms other keys abort Page 26 DL2e Hardware Reference Hardware Reference Starting and Stopping Logging Starting logging Chapter 3 Starting and Stopping Logging Starting logging Logging may be started from the keypad or using the PC s DL2 Control Panel program Three different methods of starting the logger are available e Immediate start e Pre set time start e Event triggered start Any data stored in the logger is erased on starting The logger issues a warning to remind you that data is to be erased If the logger is programmed with a password you will have to enter the password in order to pr
127. measurement as described on pages Analogue Input Card type LAC1 on page 69 or 4 Wire Card type LFW1 on page 75 e Fit the shunt resistor R4 to the screw terminal block and connect the sensor Using LPR1 or LPR1V e Fit the shunt resistor resistor R on LPR1 or LPR1V for the channel required Do not cut the track on the underside of the board e Set the LAC1 for 15 channel or 30 channel operation and connect terminal group s to the appropriate position on the card see Capabilities on page 80 Link L1 e Sensor connections to the screw terminal block can be single ended or differential see Voltage single ended on page 86 or Voltage differential on page 89 Fit link L1 if required Selecting a shunt resistor e Use a precision resistor or calibrate e Ensure that your current source has enough drive voltage For example using a 100Q shunt resistor to measure a 4 20mA transducer the sensor needs to provide a maximum voltage of 20mA x 100Q 2000mV 2V e Check that the resistor you choose can dissipate sufficient power For example a 100Q shunt resistor driven by a 4 20mA transducer will need to dissipate 20mA x 2V 40mW Standard 0 25W resistors are suitable e Avoid very low value shunt resistors as contact resistance can contribute significant errors Calibration optional e Program the divided channel with sensor code VLT e Apply a precise current Iin and READ the channel to obtain Vread Vread
128. measurement error e The voltage is measured on range 3 so resolution is 64u V e Differential offset is 10uV logger at 20 C e The reading error at 49 96mV is 0 07 x 49 96mV 0 035mV 35uV Resolution plus voltage offset 64u V 10u V 74uV is greater than error so take 7AuV as the voltage measurement error 4 Convert voltage measurement error into resistance R V I e Using V I error in measured resistance is 74uV 20UA 3 70 5 Calculate additional resistance reading errors e for 20uA excitation current 0 05 x 2 498 x 10 Q 1 250 e for 2 wire resistance measurements 20Q 6 Combined worst case resistance reading error is 3 7Q 1 25Q 20Q 24 950 8 Convert the resistance reading error into a temperature e Using the table on page 153 the resistances at 22 5 C and 17 5 C are 2 234 KQ and 2 800 KQ e The change in resistance over a 5 C change in temperature is 2 800 KQ 2 234 KQ 0 566 KQ 566 Q e The change in temperature for 1 C temperature change is 566Q 5 113 20 e 24 95Q resistance reading error corresponds to a temperature error of 24 95Q 113 2Q 0 22 C Answer the maximum logger error is 0 22 C Page 147 Appendix B Accuracy of logger readings Appendices Arithmetic accuracy Analogue sensors linear conversion to engineering units The logger stores readings from analogue sensors as raw data with no additional loss of accuracy other than the analogu
129. ment of small changes from a base resistance value A typical application is PT100 measurements When ON it is applied to every resistance measuring channel on the card The offset is factory set for optimising PT100 temperature measurements in the range 20 C to 60 C It can be adjusted as required Bridge measurements Bridges can be excited using either a voltage or current source The bridge output is measured as a differential voltage e Voltage excitation is provided for each channel The voltage source is factory set to 1 048V but can be adjusted up to 4V if required The voltage source can supply 60mA which has to be shared between all voltage excited channels in a terminal group The voltage source is applied to all 6 channels in a terminal group whenever a reading is being taken from any channel in the group e Current excitation the current source normally used for resistance measurements is available on each channel for bridge excitation Potentiometric measurements The voltage and current sources can be used to excite a potentiometer The potentiometer output measured as a differential voltage represents a ratio of resistance s and is independent of the absolute resistance of the potentiometer Input protection DL2e Hardware Reference The and yw terminals on the LFW1 are protected against a continuous overload voltage up to 15 volts Inputs can also survive brief spikes at much higher voltages the shorter t
130. month irrespective of the date format The logger s clock is actually set at the moment you press SET TIME to set the number of seconds fite 28 01 pine 15 29 30 Page 18 DL2e Hardware Reference Hardware Reference Interrogating the DL2e logger Logger status Chapter 2 Interrogating the DL2e logger This chapter describes facilities that allow you to examine the current state of the logger Status information is supplied on the following e Logger including battery voltage date and time logging program name and memory status e Sensor channels comprising instantaneous readings on input channels and status of relay and event trigger channels If using the logger s keypad relay channels can also be exercised i e turned on and off for testing purposes e Datasets including the amount of memory used and available e Errors malfunctions reports i e whether any problems have occurred while the DL2e Logger has been logging including full memory battery failure and suspect data on input channels Malfunction reports can be deleted so that only new malfunctions get reported on the next occasion Either WAKE the logger from the Front Panel or run a DL2 Control Panel on your PC General Status Report Logger status A general status report appears transiently on the Front Panel when you wake the logger This information may also be viewed in the DL2 Control Panel on your PC See also the on line Help av
131. mperature on channel 1 is below 20 C Explanation On starting logging the logger monitors a temperature on channel at 1s intervals and stores a 4 hour average The warm up relay channel 63 switches on and off with a repeat period of 5s When the reading on channel 1 rises above 20 C relay channel 64 closes Event trigger channel 62 can now detect the switching of relay channel 63 Each time the warm up relay opens i e turns the warm up off channel 62 detects an event and records TRIG 62 data from channels to 5 When the reading on channel 1 falls below 20 C the switching of the warm up channel is no longer visible to the event trigger channel and no further TRIG 62 readings are logged until the reading on channel rises again LOG LOG status Temperature control output threshold channel 1 reading ON e channel 64 status i OFF ON g channel 63 status OFF i aH EVENT i j EVENT Status Figure 37 Timing diagram for intermittent logging Manual control of logging To log data on demand from an operator a manually operated switch can replace the control output relay channel DL2e Hardware Reference Hardware Reference Sensors and Input Cards Intermittent logging using relay and event trigger combinations Example Program and Wiring for Intermittent Logging 4h Avg of Thermistor 2K type Fenwal UUA32I2 1s samples Batia ie Tae Thermistor 2K t
132. msec SCAN OVERHEADS 1 Awake Asleep Smoter o Jo dts SERVICING TIMES PER READING 41 Ranging down Ranging up extra for autoranging 4 40 per range 80 80 per range LACI 30 ch mode All other analogue resistance channel types extra for autozero 5 per 41 analogue reading type per terminal group Extra for processing Analogue Reading 2 3 linearisation 17 cold junction referencing 6 32 extra to linearisation STORAGE TO MEMORY Storing a single Calculating and reading storing an average jos DL2e Hardware Reference Appendices Appendix C Calculating the speed of data readings NOTES DL2e Hardware Reference 1 SCAN OVERHEADS is the time taken for the logger to prepare for taking readings at the beginning of a LOG or EVENT and performing housekeeping calculations when finished 2 The time required for an analogue reading depends on the magnitude of the input signal Full scale is with respect to the voltage range being used If autoranging the full scale figure applies for inputs of 4mV 32mV 262mV 2 048V and for corresponding resistance values Vin R X Lexcitation 3 The timings quoted above apply for the 50 60 switch set to the European mains frequency 50Hz When set to 60Hz all analogue timings are approximately 20 faster see Electrical mains environment on page 48 4 Autoranging to a less sensitive range is slower than to a more sensitive range and require
133. n board digital channels 61 62 input stage schematic diagram Page 116 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Digital inputs and Counter Card type DLC1 Setting up DLC1 Ribbon cable e Connect to any terminal group If using terminal group 1 15 ensure that both halves of the cold junction thermistor switched are in the OFF position see Figure 25 Sensor connections 3 wire resistance Counting at high frequencies e For appropriate channels remove or replace the socketted input capacitor as shown opposite For 1MHz frequency response replace the IMQ input resistor with 100 kQ The input components for channels 1 15 are numbered on the card See Appendix E if using channel numbers higher than 15 Min pulse Max Input Input width frequency capacitor resistor square wave 500 Hz 410 pF 15 kHz 10 pF 1MQ 30 us 500 kHz 100 kQ If a clean 0 5V e g CMOS logic output signal source is used the above maximum frequencies may be doubled Setting up on board channels e Ifa single data trigger channel is required use channel 62 rather than 61 Otherwise some RAM will not be available for timed data Programming Issues Programming an Input Channel In DL2 Program Editor if using a DCL1 Counter card select Input Card Type DLC1 for the channel group that is connected to the DLC1 card For channel group 61 62 Input Card Type for is automatically set to On board digital channels
134. nel Relay channel checking operation fuses warm up Relay channel relay channels excercising Reset cold coldboot warm resistance 2 wire Resistance accuracy Resistance measurement 2 wire 3 wire 4 wire small changes using LFW1 with offset Resistance offset calibration Resistance temperature detector RTD Resistor bridge completion shunt voltage divider Resolution lagged data Ribbon cables fitting and removing 13 33 33 33 10 11 49 19 106 131 111 106 115 63 109 76 15 49 pA 57 13 23 57 46 143 22 121 123 122 22 121 22 24 15 16 70 146 62 69 73 75 101 69 73 104 75 106 63 76 63 75 106 76 131 109 80 98 80 92 26 68 Page 159 RS232 cable RS232 port configuration RTD s function Sampling errors Sensor bipolar output errors malfunction powering Sensor connection 2 wire resistance 3 wire resistance 4 wire resistance bridge current differential voltage fully floating potentiometric PT100 and RTD s single ended voltage thermistor thermocouple sensor connections relays Sensor connections differential voltage single ended voltage sensor connections relays Sensors status Service and Spares SET event trigger SET TIME function Setup string for PRINT Shunt resistor Shunt resistor Signal analogue digital low level voltage Single ended voltage Single ended voltage Single ended voltage measurement Size of da
135. nge 20 to 60 C Although thermistors can t match the accuracy and stability of high quality Platinum Resistance Temperature Detectors they are considerably easier to use When used with the logger for environmental temperature measurements thermistors can give temperature measurements of accuracy comparable with PT100 s at a fraction of the cost Thermistors are available in a variety of forms e nominal resistance values range from tens of ohms to megOhms at 25 C e temperature range around 80 C to 150 C is common but wider temperature range versions to 100 s of C are available e accuracy 0 2 C is common more expensive 0 1 C versions are available e shape and size The commonest form is encapsulated in a match head sized bead Other forms are available for specialist applications for example miniature chip thermistors which are suitable for suitable for attaching to leaves for measuring leaf temperature Among the commonest are Fenwal Unicurve 2K 2K252 10K and 100K The logger has resident linearisation tables for these thermistors covering the range 20 C to 60 C These are given sensor codes TM1 to TM4 Using thermistors with the logger Sensor Connections High resistance thermistors 10K to 100K 2 wire connection using LAC1 in 30 ch mode give adequate results 2uA excitation current has to be used for measuring resistances greater than 100KQ and there is a possibility of introducing significan
136. not another thermocouple e Leave the cold junction channel with no sampling interval if you are not interested in logging the cold junction temperature itself Then enter the cold junction channel number for the thermocouple channel Page 134 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Thermocouples Accuracy As mentioned above thermocouples in themselves are not very accurate There are further contributions from cold junction temperature error as a result of non isothermality and from logger input offset voltages Logger contribution to thermocouple errors The tables below show the errors arising from the logger s measurement of thermocouple voltages Maximum logger contribution to thermocouple errors uncompensated Measurement range 20 C to 60 C 120 C to 200 C Logger temperature 20 C 20 C to 20 C 20 C to 60 C 60 C Logger Error Thermocouple A cold junction measurement error has to be added to these figures Logger 20 C 20 C to 60 C temperature Thermistor contribution C Logger contribution 0 14 C 0 17 C Maximum total 0 24 C_ 0 30 C DL2e Hardware Reference Page 135 Appendices Appendices Page 136 DL2e Hardware Reference Appendices DL2e Hardware Reference Page 137 Appendix A DL2e Technical Specifications Appendices Appendix A DL2e Technical Specifications Logging Logging interval and speed 1 5 10 30 sec 1 5
137. ntinuously varying values The logger fitted with an analogue input card can be used to measure DC voltage current and resistance Page 60 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Overview of electrical measurement techniques Analogue input cards There are three analogue input cards for the logger types LAC1 ACD1 and LFW1 Any channel on these cards can be used for DC voltage current and resistance measurements LAC1 The LACI card is a general purpose analogue card It can be set up to provide 30 analogue channels using two terminal groups for less demanding applications or 15 channels occupying a single terminal group for higher precision measurements The mode of operation 15 ch or 30 ch is determined by the position of a slider switch on the card and ribbon cable connections to the card The two modes of operation are distinct and should not be confused They require different sensor connections and have different capabilities Refer to page Analogue Input Card type LAC1 on page 69 for details ACD1 The ACD1 card provides up to 15 channels for AC DC voltage measurement Inputs can be 2V dc or 2V ac rms and two or three wire resistance measurements Measurements of ac are true rms AC Excitation Source Card type ACS1 is also available for use with this card LFW1 The LFW1 card provides up to 12 channels 6 channels per terminal group It can be used for sophisticated analo
138. o 30 ch mode if reduced accuracy is acceptable lsothermality The logger s terminal panel is designed to be isothermal under stable conditions of use e Avoid situations that can cause temperature differences to develop across the terminal panel resulting in cold junction errors For example gt Thermocouple cables warmed by exposure to direct sunlight or other heat sources can conduct heat into the terminal panel gt Rapid change in the logger s temperature e g moving it from a cold to a warm place can cause uneven warming or cooling of the terminal panel Programming the logger J K T type thermocouples The logger has resident linearisation tables spanning the range 120 C to 200 C for J K and T type thermocouples e Use the corresponding sensor codes TCJ TCK TCT respectively The tables are listed in Appendix E Other thermocouple types e Create a new sensor code and enter a linearisation table Note that the table must include the expected cold junction temperature to enable the logger to perform cold junction compensation calculations Cold junction compensation e Program the cold junction channel before the thermocouple channel itself gt On board thermistor specify sensor code TM1 for channel 1 gt Other cold junction channel program a channel as a temperature measuring channel Note that the logger requires cold junction channels to be linearised channels expecting an RTD or thermistor but
139. o the surrounding medium by any of conduction convection and or radiation EXAMPLE A miniature 1 7mm diameter PT100 probe has a self heating error of 0 43 C mW in still air falling to 0 08 C mW in 1m s moving air If it were logged every second with 2mA excitation current in still air at 0 C self heating error 0 43 C mW x PR x duty cycle 0 43 C mW x 2mA x 1000 x 0 1sec sec 0 43 C mW x 0 4mW x 0 1 0 017 C Polarisation Certain types of sensor suffer electrical polarisation for example gypsum block soil moisture sensors Use the ACS1 ACD1 combination for measuring these resistances Leakage Small leakage of excitation current may occur The 2uA range is particularly susceptible because a small leakage will have a proportionately large effect To minimise inaccuracies due to leakage e Avoid the 2uA excitation current wherever possible e Take precautions against formation of moisture films in damp conditions the commonest cause of leakage gt Ensure the logger is fitted with fresh desiccant gt Spray contact oil on terminals and keep the terminal compartment dry e Varistors used on the LPR1V card are susceptible to leakage Avoid 2uA excitation current with LPR1V especially Page 108 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Bridge measurements Bridge measurements The LFW1 card is required for bridge measurements Bridge circuits allow small changes in the resistan
140. oceed As soon as the logger receives the instruction to start logging it considers itself to be in a logging condition The Logger Status indicates that Logging has started Resetting the logger s clock is not permitted even if the logger has not yet logged any data In particular note that this applies to timed and event triggered starts when a considerable time interval can elapse between issuing the instruction to start logging and actually storing the first data The logger stores the time of receiving the instruction to start This is the time reported in the Logger panel of the DL2 Control Panel see Logger on page 19 and does not coincide precisely with the time of the first logged data even for immediate start Immediate Start This method of starting occurs if logging is started from the keypad or if the immediate start option is selected using the PC The logger sets its clock to log timed data as soon as possible after receiving the command to do so There may be a 2 second delay between issuing the command and the first logged timed data If a start trigger channel has been programmed event triggered starting occurs instead see below To start logging at a pre set time Using the PC the logger can be made to start at a pre set date and time for example on 31st January at midnight Event triggered start The logger can be armed to start logging when a signal is detected on channel 61 The logger must be programme
141. ogged since the last collection is protected from erasure until it has been collected Event triggered data When erasing event triggered data the logger erases all data of the specified data type up to the current time irrespective of whether it has been previously collected There is therefore a risk of erasing data that has not been collected from the logger for example if an EVENT occurs between collecting and erasing event triggered data To minimise this risk you should confirm that the number of event triggered data stored corresponds to the number of data that you have already collected before erasing event triggered data Protection from erasure Data can be protected from being accidentally erased by configuring the logger with a password see page 17 Using Ls2Win In the Datasets panel of DL2 Control Panel select the dataset in which you want to erase readings and click Delete Retrieved Records or Delete All Records Using the keypad display DL2e Hardware Reference At the Keypad main menu press PRINT If the logger has been auto printing it stops auto printing and exits the PRINT function Press PRINT again to proceed with erasing data ending auto print In the menus that follow use and Tto toggle between the options and press PRINT to select the displayed option Select ERASE Press PRINT Page 37 Collecting and Erasing Logged Data Hardware Reference Erasing data from the logger s memory
142. ogram If you change the logger s communication parameters then either reset the logger s internal switches to their original positions after printing or modify the settings in the Properties window next time you use the DL2 Control Panel program Handshaking Set the printer for hardware handshaking see Handshaking on page 36 Connection to printer Connect the printer to the logger s RS232 connector using a suitable cable and set the printer on line Checking printer operation A simple test is available to ensure that the logger is communicating correctly with a printer At the logger s main menu press T The logger outputs a sequence of printable characters lt DOWN gt printer test _ If the logger and printer are correctly connected and set up the printer will repeatedly print out the following sequence amp 0123456789 lt gt ABCDEFGHIJKLMNOPQRSTUVWXYZ abcdefghijkImnopqrstuvwxyz To stop the printer press any key DL2e Hardware Reference Page 33 Collecting and Erasing Logged Data Hardware Reference Outputting data directly to a printer Page 34 Troubleshooting printer problems Common problems and likely causes are Likely cause No printout at all or very intermittent Faulty or incorrectly wired cable printing Complete nonsense Logger printer baud rate or data bits setting not matched Approximately half of the printout Logger printer par
143. on see page 23 Page 22 DL2e Hardware Reference Hardware Reference Interrogating the DL2e logger Sensors status On exiting the status report warm up relays are returned to the state required for logging i e ON in a warm up period OFF otherwise However if logging is in progress the logger switches warm up relays OFF at the end of a warm up period even if they have been switched ON for a Channel Report If this occurs you will see faulty readings from warmed up channels Event trigger channels Event trigger channels are reported as being either a s trigger start trigger or d trigger data trigger with a status SET or CLR clear When SET the channel detects events and the logger acts accordingly When CLR the channel ignores events Both start and data trigger channels are CLR when the logger receives a program and become SET when logging is started When a start trigger detects an EVENT the logger starts recording data and the start trigger becomes CLR ignoring any further events Data trigger channels remain SET until logging is stopped or event triggered memory fills up Using Ls2Win Sensor status information is displayed in the Sensors panel of DL2 Control Panel See also its on line Help and Lesson 2 in Getting Started Using the keypad display At the Keypad main menu press READ The logger displays the sensor code and label for channel 1 or the first programmed channel in numerical order if
144. on page 75 gt DLC1 Digital inputs and Counter Card type DLC1 on page 115 Do this before fitting another card on the input stack while all the components on the card are accessible Remo ving and fitting ribbon cables Do not apply excessive force to the hook shaped latches as they are easily broken e When fitting ribbon cables ensure that the connectors mate completely before hooking the latches over e When removing a ribbon cable gently pull both latches back just far enough to eject the ribbon connector e Note that the ribbon cables are not symmetrical If you are having trouble making a ribbon cable stretch far enough try reversing it Terminal labels are supplied with the logger and with each input card Use these to number the screw terminal blocks for your card Page 68 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Analogue Input Card type LAC1 Analogue Input Card type LAC1 The LACI is a general purpose analogue input card It can be set up as a 30 channel card 30 ch mode for simple analogue measurements or as a 15 channel card 15 ch mode for higher precision applications 15 ch mode Capability Channels 15 channels are available on one terminal group Voltage inputs Differential A wire link can be fitted on the screw terminal block for single ended measurements This gives better offset performance and accuracy than 30 ch mode single ended measurements Resistan
145. ontains data and is programmed with a password you will be prompted to enter it password The logger prompts you to press START again to confirm that you want to start logging and erase any previous data Press any other key if you decide not to start logging lt START gt confirms other keys abort If the logger has been programmed with a Start trigger channel a message appears indicating that the start trigger is set i e awaiting a signal to start logging start trigger set If there is no start trigger channel the first LOG starts after 1 to 2 seconds l other keys abort logging started The message LOG appears briefly indicating that a set of timed readings has been taken other keys abort LOG ing started Page 28 DL2e Hardware Reference Hardware Reference Starting and Stopping Logging Stopping logging Stopping logging Logging may be stopped by using either the front panel keypad or via the PC There is also an internal STOP button Note there are no facilities using an event trigger to stop logging nor for stopping at a pre set time Stopping logging is protected by passwords except if the STOP button is used There is no need to stop logging in order to collect logged data or to use any other Windows software or front panel function Logging stops automatically in the event of a battery failure If the memory available for a data type TIMED TRIG 61 TRIG 62 fills up t
146. ookmark not defined for details The 6 function is for testing one way serial communication e g with a printer See Checking printer operation on page 33 for details DL2e Hardware Reference Hardware Reference About the DL2e Logger Resetting the logger Resetting the logger Coldbooting Coldbooting restores the logger to a known basic state with the following consequences e Any data stored in the logger is erased e The logger carries out a RAM check checking which RAM chip positions are occupied and whether any RAM chips are faulty e The existing logging program is erased and the default configuration is installed e Any Setup string for PRINT is erased XXXX See Setup string for PRINT in the on line Help e Auto wrap previously called the overwrite mode is disabled See Auto Wrap in the on line Help The logger s clock is not reset The logger automatically coldboots on waking if a new PROM is installed The logger must be coldbooted if e RAM chips have been moved or installed e The logger has crashed irretrievably for any reason and a warm reset see opposite fails e Input cards have been removed or installed i e plugged into or out of the input card stack The logger does not need to be coldbooted if only switches or ribbon cables have been moved or if attenuator or input protection cards types LPR1 LPR1V have been installed To coldboot the logger DL2e Hardware Reference Open
147. oops can cause significant and unpredictable problems and they should be avoided in all situations Voltages can be generated in metalwork by effects that you may be unaware of for example electrochemical and thermocouple effects of dissimilar metals in contact with each other In electrically noisy environments electrical induction can cause currents to flow in earth loops resulting in unstable or inaccurate readings Page 95 Sensors and Input Cards Hardware Reference Earth loops and common mode voltages Page 96 Configurations which are prone to earth loop problems include e Multiple thermocouples attached to common metalwork e g motor vehicle chassis If electrically isolated sensors are not practical connect one sensor as single ended and the others as differential e Sensor and logger powered from a common power supply If the sensor output is electrically isolated from the sensor s power supply then you should use single ended Otherwise common earth or low impedance common mode use fully floating differential connections e Using non isolated mains power supplies Most mains power supplies such as regular plug in mains DC adapters are fully isolated If you use more than one non isolated power supply in your logging system mains earth provides a potential earth loop route Again beware of creating earth loops with single ended sensor connections e Connecting a logger to a mains powered computer might be a po
148. oring timed data if the logger finds that the time for its next LOG has already passed Whenever this happens the logger saves time by storing copies of previous readings or adding them to averages etc instead of taking new readings This is very unlikely to occur in normal use but might happen if e The logger is programmed to read faster than it is able to e g 60 thermistors every 5 seconds See Appendix C for information about logging speed e The logger is programmed to read close to the limits of its speed and an unusual coincidence causes it to be exceptionally slow e g all channels requiring autoranging on the same LOG as can happen on the very first LOG e The logger is programmed to log timed and event triggered data and the length of time spent recording triggered data is sufficient to cause it to over run on timed readings Storing faulty data Readings involving either sensor malfunctions or over runs are recorded with lower resolution 10 bits instead of 12 bits See also the on line Help Faulty readings do not contribute to the minimum and maximumvalues in data file headers See also the on line Help If problems occur with individual readings on a channel employing data compression the resulting compressed values are flagged accordingly Deleting malfunction reports Malfunction reports can be deleted from the logger s memory so that in future the logger reports fresh occurrences of malfunctions only Deleting
149. otice appreciable delays in responding to your key presses while the logger is busy performing a priority task If the logger is programmed to log timed data very frequently you may find it difficult to establish communication with the logger and data collection may be appreciably slower than normal Occasionally the logger may attempt to display the message off screen off the edge of the logger s display This is unusual most likely to occur when the logger is displaying a General status report You may then notice a delay in keypad operation without any message being displayed Conflicting priority tasks DL2e Hardware Reference It is possible for an event trigger to occur while the logger is busy logging timed data and for timed data to become due while the logger is servicing an EVENT If so the logger completes the first priority task before tackling the second one As aresult there may be a discrepancy between the time recorded by the logger in its data file and the actual time when an EVENT occurred or when data was actually logged see Timing accuracy on page 118 for details If a LOG becomes due while the logger is still working on a previous LOG an over run occurs see Over runs on page 26 for details EVENT detection is disabled on an event trigger channel while the logger is busy servicing a previous EVENT on the same event trigger channel The logger may miss events occurring in short succession Page 11
150. ove the lid of the logger e Disconnect the logger from computers printer and external power supply Remove internal batteries and the lithium cell e Remove any LPR or LPR1V cards from the top of the stack e In newer loggers the top card in the input stack is retained by four slotted nylon nuts Use a screwdriver to remove these nuts and replace them with the standoff pillars supplied with the card e Position the long pins on the underside of the card in the corresponding socket on top of the input card stack and gently push down Make sure that the pins are not offset from the socket and that the pins are not bent When the card is correctly positioned the four corner holes will align with the studs at the top of the standoff pillars e Replace any LPR1 or LPR1V cards at the top of the stack e Screw down the four slotted nylon nuts on new style loggers or the standoff pillars supplied with the card older style loggers onto the protruding studs to secure the board in position e Re connect the logger s power supplies remembering to replace the lithium battery The logger will coldboot e Set up the input card and fit ribbon cables to the terminal panel as described in the following sections gt LAC1 Analogue Input Card type LAC1 on page 69 gt ACD1 Analogue Input Card type ACD 1 on page 73 Page 67 Sensors and Input Cards Hardware Reference Input and supplementary cards gt LFWI1 4 Wire Card type LFW1
151. ower supply or from a completely separate power supply The logger s power supply can be shared with devices requiring an unregulated supply at 7V to 15V DC Sensors sharing the logger s power supply should have an output which is either fully isolated from the power supply or else has a common mode voltage less than 2V with respect to the power supply earth Three different relay functions are available for controlling relay switching Warm up Used for powering up sensors a short time before taking a reading Control output Used for switching when the reading on an input channel crosses a prescribed threshold Malfunction warning Used for switching when the logger detects a logging malfunction See also Relay Channels in the on line Help for Ls2Win Electrical specification Relay type Changeover or single pole double throw SPDT with common labelled 63 and 64 normally open NO and normally closed NC terminals gt Relay nominally OFF NO isolated NC connects to common gt Relay nominally ON NO connects to common NC isolated Switching capacity 50V 1A maximum Power via jumpers When using the logger s internal power supply the available voltage is the battery voltage as seen by the logger This is equal to the logger s internal battery voltage or when switched to external power supply one diode drop around 0 7V less than the actual power supply voltage DL2e Hardware Reference Pa
152. pen type There is 50u A additional current consumption for each switch closed Counters are rising edge triggered The count increments when the switch opens or the logic input goes high Counter capacity Each channel can count up to 65 472 in each sampling interval An over range error is shown is this limit is exceeded Frequency response Counter card DLC1 As supplied the input frequency is limited to a 500Hz square wave or I ms input high period Briefer pulses are not counted An RC filter on each channel limits the frequency response to reduce noise pick up and to debounce mechanically switched inputs preventing multiple counts from switching noise Higher frequency pulses from digital logic can be counted by modifying the RC filter components as described below Bursts of pulses at frequencies up to 500kHz can be counted provided that the total count in a sampling interval is less than 65472 On board channels 61 62 These have a fixed 100 Hz frequency or 5ms pulse response Page 115 Sensors and Input Cards Hardware Reference Digital inputs and Counter Card type DLC1 Ribbon cable from any terminal group Input resistors Input capacitors Figure 30 DLC1 counter card 3U 5U X Y to counter 470pf lt Ci 15 3U when asleep 5V when awake Figure 31 DLC1 input stage schematic diagram 4 3U75UX to counter and interrupt controller k 3U uhen asleep 5U when awake Figure 32 O
153. ppendices A and B Additional errors inherent in 2 wire measurements are DL2e Hardware Reference Page 101 Sensors and Input Cards Hardware Reference Resistance 2 wire e The resistance of connecting cables which is included in the resistance measured by the logger e LACI in 30 ch mode has an additional 20Q 6Q typical error Remarks e Minimise cable resistance errors by using short cable runs of thick low resistance cables LAC1 30 ch mode has an internal series resistance of 690Q max The full scale resistance that can be measured is thus reduced from the nominal value for each excitation current For example when using 200uA excitation current the actual full scale will be 10500Q 690Q 9810Q worst case See also 3 wire connection for LAC1 under Resistance 3 wire on page 104 4 wire connection for LFW1 under Resistance 4 wire on page 106 Page 102 DL2e Hardware Reference Hardware Reference LAC 1 30 channel mode LAC 15 channel mode LEWI Figure 23 Sensor connections 2 wire resistance DL2e Hardware Reference Cold junction thermistor switch Ws 15730 Switch set to 30 Cold junction thermistor switch 15730 switch set to 15 PRT ZR switch set to R Sensors and Input Cards Resistance 2 wire Sensors and Input Cards Hardware Reference Resistance 3 wire Resistance 3 wire The LAC1 card in 15 ch mode or ACD1 can be used for 3 wire resistance m
154. r channels are reset when they are logged and each logged reading represents the number of counts accumulated since the counter was last logged EXAMPLE tipping bucket rain gauge Each tip of the bucket briefly closes a switch The counter channel detects and counts the switch closures and the recorded number of counts represents a quantity of rainfall Frequency Again the logger counts pulses continuously but calculates an average frequency by dividing the accumulated count by the sampling interval EXAMPLE anemometer Each rotation causes a brief switch closure A frequency channel counts the switch closures and divides by the sampling interval This may be scaled to give the average wind speed over each sampling interval Event An event trigger channel detects a rising edge transition between digital states Depending on the configuration of the event trigger channel e data trigger the logger records the date and time and data from specified channels to memory reserved for event triggered data e start trigger the logger starts logging just as if it had been started manually The logger has two on board digital channels which are present in all loggers which can be used for any of the above functions Counter cards type DLC1 can be fitted to the logger Each counter card gives the logger an additional 15 counter or frequency channels not digital status or event trigger Analogue signals Analogue signals have a co
155. r of channels in data file h Data type TIMED TRIG 61 and TRIG 62 Channelheadere 90 38 30s 9038 30 Date timed 24 8 1i lf Using Ls2Win Page 32 In the Datasets panel of DL2 Control Panel select the dataset in which you want to erase readings click Retrieve and make suitable selections in the Retrieve Dataset dialog DL2e Hardware Reference Hardware Reference Collecting and Erasing Logged Data Outputting data directly to a printer Outputting data directly to a printer The front panel PRINT function is used to output data directly from the logger to a printer You may find it faster and more convenient to use the PC to collect data to a disk file and to obtain a printout from that see the on line Help Preparation Requirements e a printer with an RS232 serial interface not parallel e a suitable cable Communication cables on page 51 describes how to construct a suitable cable Loggers to computer cables are generally not suitable Communication parameters The logger s communications parameters baud rate data bits and parity must be set to match those of the printer see Communication parameters on page 50 Refer to your printer s manual for information about setting the printer s communication parameters When the logger is subsequently connected back to a PC the logger s communication parameters must be reset to match those in the Properties dialogue of the PC s DL2 Control Panel pr
156. ration etc The logger can be woken to resume normal operation after a warm reset Warm reset is not as drastic as coldbooting Try it in preference to coldbooting if the logger crashes and gets stuck in an awake state Coldboot only as a last resort if a warm reset fails The logger normally autosleeps of its own accord and warm reset should not be used to routinely put the logger to sleep In particular beware of resetting the logger while it is in the middle of a LOG EVENT or WARM UP This may interfere with the setting of the logger s clock in preparation for the next LOG and have an unpredictable effect on logging of timed data To carry out a warm reset e Open the logger s case e Press and release the RESET button see Figure 2 When the button is released the logger s display goes blank e Repeat if necessary Page 16 DL2e Hardware Reference Hardware Reference About the DL2e Logger Password Password The DL2e Logger has a password facility for preventing loss of data or interruption of logging due to unauthorised use of the logger s keypad or PC software The password is set up as part of the logging program Once the logger is programmed with a password the user has to enter it in order to perform the following operations e erase data from the logger s memory e stop logging e start logging if data is stored in the logger e re program the logger if data is stored in the logger The pa
157. re earth paths already exist such as gt electrically interconnected sensors for example arrays of thermocouples in contact with metalwork groups of sensors sharing a common power supply gt sensor sharing the logger s power supply gt multiple mains power supplies if not fully isolated including a mains powered computer The alternative is to use fully floating differential connections These can in turn give rise to common mode problems See Earth loops on page 95 for a discussion of earth loops and common mode problems Current measurement Current is measured by fitting a precision shunt resistor in parallel with the current source and measuring the voltage generated across the resistor gt Vmeasured T Rorecision LAC1 ACD1 and LFW1 cards can be used for current measurements and the guidelines for choosing between single ended and differential connections apply in the same way as for voltage measurements see above The precision resistor can be fitted directly to the logger s screw terminals Alternatively if using a LAC1 or ACD1 the resistor can be mounted on an LPR1 or LPRIV card Examples of current source sensors are 4 20mA sensors photodiodes Resistance measurements For general purpose resistance measurements the logger passes a precision excitation current through the resistor measures the voltage drop across it and calculates the resistance using Ohm s law Vmeasured R I known
158. re routine with unpredictable consequences Ata battery voltage of around 3V the lithium cell backup battery takes over It provides power for retaining configuration information and stored data in the logger s memory and for keeping the logger s clock going Replacing batteries When replacing batteries e Use alkaline cells only Other less expensive types of primary battery are not suitable They can leak corrosive chemicals and cause permanent damage to the logger e Ensure you insert the batteries the right way round as indicated on the battery holder e Always replace a complete set of batteries Don t mix batteries that have been discharged by different amounts You can change batteries without stopping logging but you must ensure that you can complete the procedure while the logger is asleep between LOGs If the logger s power supply is interrupted during a LOG it may be unable to resume after the power supply is restored If you need to change the batteries and continue to log data at frequent intervals provide an external power supply while changing the batteries Lithium cell Page 42 The lithium cell is mounted on the logger s main circuit board see Figure 2 Main circuit board layout on page 40 It provides backup power for the logger s memory and clock for a period of up to 2 months If the logger is to be stored away or left inoperative for a period of time remove the lithium cell to avoid d
159. refer to have such returns discussed with us in advance and we may at our discretion waive these charges Delta T shall not be liable to supply products free of charge or repair any goods where the products or goods in question have been discontinued or have become obsolete although Delta T will endeavour to remedy the buyer s problem Delta T shall not be liable to the buyer for any consequential loss damage or compensation whatsoever whether caused by the negligence of the Delta T our employees or agents or otherwise which arise from the supply of the goods and or services or their use or resale by the buyer Delta T shall not be liable to the buyer by reason of any delay or failure to perform our obligations in relation to the goods and or services if the delay or failure was due to any cause beyond the Delta T s reasonable control Service and Spares Users in countries that have a Delta T Agent or Technical Representative should contact them in the first instance Spare parts for our own instruments can be supplied from our works These can normally be despatched within a few working days of receiving an order Spare parts and accessories for sensors or other products not manufactured by Delta T may have to be obtained from our supplier and a certain amount of additional delay is inevitable No goods or equipment should be returned to Delta T without first obtaining the agreement of Delta T or our agent On receipt a
160. rement Connection Requirements combinations e AC Voltage Voltage AC e DC Voltage Single ended Differential low CM Differential high CM e Resistance 2 wire 3 wire e Thermocouple Single ended Differential low CM Differential high CM Page 74 DL2e Hardware Reference Hardware Reference Sensors and Input Cards 4 Wire Card type LFW1 4 Wire Card type LFW1 The 4 Wire Card type LFW1 is an input card intended mainly for measuring sensors needing 4 wire connection These include bridge connected sensors such as strain gauges and low value resistors such as platinum resistance thermometers PT100 4 wire resistance measurements minimise cable resistance errors A voltage source and the logger s programmable current source are available to each channel for sensor excitation The sensor output is measured as a differential voltage input Capability Channels and terminal groups The LFW1 provides 1 or 2 terminal groups of 6 channels per terminal group Each channel is provided with current and voltage sources on separate terminals Voltage inputs Differential A wire link can be fitted on the screw terminal connector block for single ended measurements Resistance measurements 4 wire current excited Wire links can be fitted to the screw terminal connector block for 2 wire measurements Resistance offset A switchable offset is available for accurate measure
161. rence Sensors and Input Cards Voltage up to 50V DC Fully Floating Connection ae 15 channel mode 15730 switch set to 15 Fully Floating Connection PRT ZR switch preferably set to R Earthed sensor Bias resistors Figure 19 Sensor connections differential voltage DL2e Hardware Reference Page 91 Sensors and Input Cards Hardware Reference Voltage up to 50V DC Voltage up to 50V DC The connection schemes shown here are suitable for measuring DC voltages up to 50V Divider resistors mounted either on the screw terminals or on an LPR1 or LPR1V card in series with a LAC1 card are required for this purpose Setting up Mounting divider resistors on screw terminals e Setup LAC1 ACD1 or LFW1 and fit ribbon cables for single ended or differential voltage measurement as described in Analogue Input Card type LAC1 on page 69 and 4 Wire Card type LFW1 on page 75 e Fit divider resistors R1 and R2 to the screw terminal block You will have to solder one end of R2 to your sensor lead or provide your own terminal block Using LPR1 or LPR1V On the LPR1 or LPR1V fit divider resistors R1 and R2 and cut the track links on the underside of the card for the required channels e Set the LAC for 15 ch or 30 ch mode operation and connect terminal group s to the appropriate position on the card see Figure 12 Fitting LPR1 or LPR1V to input card stack Link L1 e Sensor connections to
162. repairs and guarantee Page 39 DL2e Logger Hardware Erasing data from the logger s memory RS 232 CONNECTION HANDSHAK SE_ECT UMP RS RISBON CABLE TO TERMINAL CARD PROM LIT IUM AJTO SLEE DISABLE JUM CR W A Porn BAUD 3AI SILECTION DIP SMIC se SET NGS LCD VIEWING ANGLE ADJUSTV NT GIN Ad NWA 827 SN MLE SERIAL No BUTTONS STOP 1LOGG NG RESET COLDBOO DIP SWITCH SETTINGS SET AS SHOWS 7 DATA BIS NG PARTY LVLN PANTY ACI WANS IN2UT PROTEC ON FUSE POWER SUPPLY SFI CT GN NK RIRAON CARI TO LID DATA EITS PARITY ON ODIVACTY 007 MAING Figure 2 Main circuit board layout Page 40 Hardware Reference FXT R AL POW R SUPPLY CONNEC OR DATA RAM DATA RAM EXPANSION DL2e Hardware Reference Hardware Reference DL2e Logger Hardware Power supplies Power supplies The logger can be powered by its own internal batteries or from an external power supply Suitable external power supplies include mains DC adapters 12V car batteries and solar power systems The power supply selector switch determines whether the logger draws power from the external power supply socket or from its own internal batteries An internal lithium cell backup enables the logger to survive short periods without a power source for example when changing batteries The logger s power supply can be accessed via relay channels 63 and 64 for powering up sensors and other de
163. rgeable battery pack e setting internal switches and rebooting e installing additional cards and components e connecting sensors e connecting cable assemblies e communications cables and modems e sensor linearisation tables e accuracy and technical specifications e maintenance storage repairs and guarantee It also contains general guidance on the scope and application of the measurement techniques supported by the logger Other Documents and Help See the Getting Started manual for e Installation instructions P e A Guided Tour for an introduction to some of the logger s facilities e Learn the basics of logger operation in the Tutorial e A brief introduction to features not covered in the tutorial View the on line Help or press F1 in each of the Ls2Win applications for help on using the Windows software Separate Contents and Indexes exist for each on line Help Hardware Reference A g i DL2 Program New DL2 Editor Control Panel Getting Started Sensor Application Notes including wiring instructions are provided on line in the So keep searching sensor library in the DL2Program Editor You can print off individual on line Help topics Use all the Indexes and Contents Lists in this manual Getting Started and in the on line Help for Ls2Win They are all different DL2e Hardware Reference Page 7 Hardware Reference About this manual Note the following specialist technica
164. rn lead contributes to the error Page 130 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Platinum Resistance Thermometer and other RTDs Platinum Resistance Thermometer and other RTDs Resistance Temperature Detectors RTDs are resistive temperature sensors made from metallic conducting materials Although other materials are in use the commonest RTD material is platinum Its temperature response is highly stable and repeatable Platinum Resistance Thermometers offer a means of making extremely accurate temperature measurements in the range 259 C to 631 C The PT100 sensor is the commonest form of Platinum Resistance Thermometer with a resistance of 100 Ohms at 0 C It is available in a number of different accuracy specifications for example Specification Accuracy DIN 0 41 C 1 5 DIN 0 08 C Unlike thermistors the PT100 and other RTDs have a positive temperature coefficient i e resistance increases as temperature rises They have a much less non linear temperature response This means that linearisation tables covering a wide temperature span can be used without introducing unacceptable linearisation errors The main disadvantage of RTDs platinum and other materials is their low temperature coefficient around 0 4 per C for platinum which means that simple resistance measurements are not adequate for making use of their potential accuracy The resistance offset facility on the LFW1 card is r
165. rs and Input Cards Input and supplementary cards Input and supplementary cards The logger can be fitted with up to four input cards one card for each terminal group Any combination of input cards is permitted e Standard analogue card type LAC1 e AC analogue card type ACD1 e 4 wire card type LFW1 e Counter card type DLC1 In addition the logger may be fitted with one or two supplementary cards which do not provide additional channels by themselves but are fitted in series with analogue input cards e Attenuator card type LPR1 e Input protection card type LPR1V The standard logger case can accommodate up to four cards in total A case height extension is available if you are using LPR1 or LPR1V cards and need to fit more than four cards in total AC excitation can be provided for sensors that require it e AC Excitation source card type ACS1 This card fits on the inside of the terminal panel and does not affect the number of input cards that can be fitted Installing input cards DL2e Hardware Reference NOTE This procedure does not apply for LPR1 LPR1V which are fitted on top of the input card stack see Capabilities on page 80 or ACS1 which fits on the terminal board see AC Excitation Card type ACS1 on page 83 e Complete any operation that you have started Ensure that the logger contains no valuable data It will be lost when you power down the logger in order to install or change a card e Rem
166. s an over range recovery cycle in addition to the reading being taken 5 The logger takes separate autozero readings for each terminal group for voltage and resistance readings at each excitation current as required for a LOG or EVENT You can minimise autozero overheads for mixed resistance readings by grouping channels that use the same excitation current on consecutive input channels in the same terminal group EXAMPLES two autozero readings are required for channels to 30 programmed as VLT channels 5 autozero readings are required for channels 1 to 6 programmed as TMI RR1 RR2 RR3 RR4 VLT as in the DEFAULT configuration 6 The logger takes a single cold junction reading for any number of thermocouple measurements in a single scan Page 151 Appendix D Resident linearisation tables Appendices Appendix D Resident linearisation tables The following pages set out the conversion tables that the logger uses to determine temperature values from measurements taken using the various thermistor thermocouple and PRT sensors the Logger can handle Page 152 DL2e Hardware Reference Appendices Appendix D Resident linearisation tables Thermistor tables Temp C Resistance kQ for sensor code and thermistor type TM1 2K TM2 2K252 TM3 10K TM4 100K Fenwal UUA Fenwal UUA Fenwal UUA Fenwal UUT 32J2 3253 41J1 51J1 600 osso ossos 24s7g0___ 22 5900 550 525 500 475 45 0 425 40 0 315 350 325
167. s used to power the DL2e and its attached sensors the whole system must be checked to ensure that no battery can be subjected to reverse currents at any time Non rechargeable batteries may swell leak or explode if subjected to reverse currents This is particularly relevant to the internal alkaline batteries if fitted It is essential to trace all the possible connections for the different settings of the INTL EXTL power selector on the main circuit board and the relay channel power select links Fig 12 2 shows an overview of the DL2e power supply connections NOTE The internal lithium battery is completely protected and can be ignored for these issues Check the following e The positive power supply routes from internal and external batteries e The analogue and digital earth and battery OV return rails External batteries may legitimately be connected to e The DL2e external power supply socket e The relay channels 63 and 64 e The counter channels 61 and 62 negative or digital earth terminal e any channel input analogue earth terminals at the end of each screw terminal connector If external battery power is connected to relay channels 63 or 64 remove the internal jumpers to the relay If external power is used to supply the DL2e but it is not connected through the l external power socket remove the internal battery OR set the INTL EXTL selector to EXTL and label it to prevent INTL being accid
168. sensors from the logger s power supply DL2e Hardware Reference Ensure that you have enough battery capacity to power your sensor s as well as the logger A single sensor may require more power than the logger itself Sharing the logger s power supply with sensors makes the logger itself vulnerable to sensor and wiring faults A short circuit in the sensor wiring can very quickly run down the logger s internal battery Separate power supplies for sensors are recommended for a more robust and secure system If your sensor output is not fully isolated from its power supply you will need to use fully floating differential connections to the logger see Voltage differential on page 89 Check that the sensor output has a common mode voltage that falls within the logger s common mode range see Common mode voltages on page 96 Otherwise you will require a separate power supply for the sensor This can be a particular problem if powering an excitation source for a bridge transducer Page 123 Sensors and Input Cards Relay channels SWITCHING EXTERNAL POWER VIW SEROV INSID LOGS Ih CASI WUM LX POS ONS CHANNEL 64 CHANNEL 63 JUM ER S OFF USING THE LOGGERS POWER SUPPLY V EWE FPOV IN3IDE LOGS_R S CASL mm JUMFER POS 7 ONS CHANAEI 84 meee CHANN LBS UMPE 263 ON Figure 33 sensor connections relays Page 124 Hardware Reference DL2e Hardware Reference Sensors and Input Cards
169. ssword does not need to be entered in order to use any other keypad or software function To program the logger with a password Open or create a logging program using the DL2 Program Editor Enter up to 8 alphabetic characters in the Password box Send the program to the logger in the normal way Note that the logger s keypad and display only offers upper case alphabetical characters and spaces If your password contains lower case or non alphabetical characters you cannot enter it from the logger s keypad You can do this using any PC software When prompted for a password Using Ls2Win DL2 Control Panel pops up the Password dialog which prompts you to enter the logger s password Remember to use upper case or you will be locked out from using some of the Keypad functions Using the keypad display When a password is required a prompt appears on the top line and the cursor moves to the left position on the bottom line password DL2e Hardware Reference Use and 6 to cycle through the alphabet When the correct character appears press the key corresponding to the keypad function you are using PRINT if erasing data START if starting or stopping logging The cursor will move to the next position Enter 8 characters If the password has less than eight characters enter spaces to make up 8 characters To enter a space press PRINT or START as appropriate without pressing or 0 Remarks You can recall
170. t Conditions of charging for 16 hours at constant voltage Do not exceed specified voltage Conditions of charging for 16 hours at constant voltage Do not exceed specified voltage 1380 0 18 V 13 65 0 18 V Current The charging current must be limited to less than 1 Amp 1398 018 V 5 C IMPORTANT WARNINGS Do not exceed the specified voltage as this can lead to the release of explosive gases and damage to the battery Do not recharge the battery pack while fitted to the logger Accidental overcharging can lead to a build up of explosive gases in the sealed external battery compartment Overload protection The battery pack is fused to protect against accidental overload In the event of a fuse blowing e Find the cause and correct the fault e Remove the battery pack described above replace the 1A fuse see Fig 12 3 and replace the battery pack Electrical mains environment The logger s analogue measurement circuitry is designed to be synchronised with electrical mains frequency This enables it to reject mains frequency noise which may be induced in signal cables installed close to mains wiring The 50 60 switch DIP switch 4 on the logger s main circuit board see Figure 2 Main circuit board layout selects 50 or 60 Hz operation and should be set to match your local electrical mains frequency This is to reduce noise on readings due to the mains supply The position of the 50 60 switch also determ
171. t Channel tab of the Channel Properties dialog select sensor type Platinum Resistance Thermometer type Pt100 3 wire bridge which is a Delta T approved sensor type provided in the standard Ls2Win sensor library Remarks If the LFW1 voltage source is inadequate for your needs for example insufficient voltage or current drive you can provide your own bridge excitation source You can then use a simple voltage channel to measure the sensor output If necessary use the logger s relay channels to switch the source on and off when taking readings Note that the output of a bridge typically has a common mode voltage equal to half its excitation voltage To avoid common mode problems ensure the external excitation source is isolated from the logger s power supply or bias the excitation source to ensure the bridge output is within the logger s common mode range see Common mode voltages on page 96 The same considerations apply to powering bridge based voltage output transducers with their own integral excitation source See also DL2e Hardware Reference e 4 wire resistance with resistance offset 1 4 bridge on page 106 Page 111 Sensors and Input Cards Hardware Reference Bridge measurements ger R PRT switch i set to R full bridge voltage excited ensure LED doesn t light up current excited half WSS bridge QO 3 wire bridge half and 3 wire bridges sharing bridge complet
172. t Delta T the goods will be inspected and the user informed of the likely cost and delay We normally expect to complete repairs within a few working days of receiving the equipment However if the equipment has to be forwarded to our original supplier for specialist repairs or recalibration additional delays of a few weeks may be expected Page 58 DL2e Hardware Reference Hardware Reference DL2e Logger Hardware Warranty and Service WARNING before returning a meter to Delta T you should collect any readings stored in the meter If the battery should become disconnected or run down while transferring to Delta T then the meter readings may be lost Technical Support Check other Support Material If you are having difficulties with this application note or the products listed within then check for support information in documents supplied with the products Individual manuals for Delta T products contain some technical support information specific to that product Check the Delta T Website Delta T put upgrades and support information on their web site This is also a useful source of free upgrades such as upgrading Ls2Win Contact Local Agent To obtain support with the information contained in this application note or other matters related to the products described here contact your local agent or distributor A list of local agents distributors is available on the Delta T web site Contact Delta T Directly If you are not abl
173. t are not available from the keypad such as timed start triggering on events collecting and manipulating logged data Password facility Certain logger functions are protected from unauthorised use by a password facility This is set up in the logging program using the DL2e Program Editor which is part of Ls2Win See also the on line Help Waking and sleeping The DL2e Logger can exist in one of two states known as awake and asleep corresponding to high and low levels of activity Awake When awake all of the logger s circuitry is powered up and all its functions are active The logger is awake during a LOG WARM UP or EVENT see opposite and while communicating via its RS232 port or performing any of the tasks controlled from its keypad There is normally a message displayed on the logger s display and this is the simplest way to recognise when the logger is awake Typical current consumption in the awake state is 40mA Asleep When asleep a minimum number of components are powered up notably the clock to keep time memory to conserve data and circuitry which enables the logger to be woken The logger s display is always blank when the logger is asleep Typical current consumption in the asleep state is 40H A Waking the logger DL2e Hardware Reference The logger wakes of its own accord whenever required to LOG EVENT or WARM UP See Logging opposite To use the logger s keypad functions press
174. t errors due to current leakages especially in damp conditions Low resistance thermistors less than 10K Page 128 LACI in 15 ch mode gives significantly better results than 30 ch mode which suffers from an additional 20Q error 2 wire connection is adequate provided that cable resistance is negligible If necessary eliminate cable resistance effects with 4 wire connection using LFW1 or minimise by using 3 wire connection to LAC1 when only one of the sensor leads contributes to cable resistance error Consider using a common return for multiple 3 wire connected sensors see Resistance 3 wire on page 104 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Thermistors Programming the logger Fenwal Unicurve and equivalent thermistors The logger has resident linearisation tables for four common thermistors spanning the range 20 C to 60 C These correspond to sensor types TM1 TM2 TM3 TM4 Theses tables are listed in Appendix D and can also be viewed copied and modified in the DL2 Program Editor s Sensor Library Other thermistors To create a new sensor you may copy and modify an existing sensor type in the Sensor Library tab of the DL2 Program Editor See the on line Help for details Remember that thermistor linearisation curves have a negative slope For maximum accuracy and resolution select the largest excitation current that covers the resistance span of the linearisation table Accur
175. t it back to a resistance error Rerror Verror Texe e Add the additional resistance reading error s from the table above Note the additional error inherent in 2 wire resistance measurements Example Taking a 4 wire reading of 1000Q with the logger at room temperature using 2000HA excitation current Voltage contribution The logger will be measuring a voltage of 1000Q x 2000uUA 2V The maximum error will be 2V x 0 07 1 4mV expressed in Q this will be 1 4mV 2000uUA 0 7 Resistance contribution Resistance contribution 1000Q x 0 05 0 52 Total maximum error 0 7 0 5Q 1 2Q Page 146 DL2e Hardware Reference Appendices Appendix B Accuracy of logger readings Calculation of logger analogue accuracy a worked example DL2e Hardware Reference This example shows how to calculate the maximum logger error when measuring a temperature in the region of 20 C using a 2K thermistor 2 wire connection to a LAC1 in 30 ch mode measured as sensor type TM1 with the logger at 20 C 1 Determine the resistance measured by the logger e Using the table on page on page 153 the resistance at 20 C is 2 498kQ 2 Calculate the corresponding voltage measured by the logger e From the sensor characteristics of the standard sensors the excitation current for sensor type TM1 is 20uA e Using V I xR the voltage measured by the logger is 2 498 x 10 Q x 20 x 10 A 0 04996 V 49 96mV 3 Calculate the voltage
176. t loop transducers on page 125 Page 99 Sensors and Input Cards Current LPRIC sith LACT TOP SIDE Ri only fitted Track link Intact UNDERSIDE Terminal mounted shunt resistor Page 100 Ll O HE s ASS yO a wae ean Q O GOLE GAL ELM Figure 22 Sensor connections current Hardware Reference aE Pe 15730 Suitch set to 30 15730 switch set to 15 DL2e Hardware Reference Hardware Reference Sensors and Input Cards Resistance 2 wire Resistance 2 wire 2 wire connection is suitable for general purpose resistance measurement where cable resistance is negligible For accurate measurement of resistance s less than about 10kQ use LAC in 15 ch mode or LFW1 LAC1 in 30 ch mode contributes an additional error of up to 200 Setting up LAGI 30 ch mode Set the 15 30 switch to 30 Connect ribbon cable s from one or two terminal groups to the corresponding position s marked s e 30 channel on the card The cold junction thermistor can be switched to channel for approximate temperature measurements See Figure 23 Sensor connections 2 wire resistance Pols 15 ch mode amp ACD1 Set the 15 30 switch to 15 Connect one ribbon cable only from any terminal group to the position marked differential on the card Sensor connection the and terminals are linked on the screw terminal block Connect the resistanc
177. ta files Sleep Specifications Speed of data readings Standing by Start immediate START function Start trigger Start trigger set starting logging immediate Starting logging event triggered immediate preset time Page 160 51 51 131 14 144 96 144 25 24 101 104 106 109 89 89 113 131 86 128 133 124 61 61 124 22 58 23 13 18 15 80 98 60 60 62 75 70 61 86 32 9 12 86 89 138 150 20 27 13 28 29 60 28 28 27 27 28 27 27 Status digital memory RAM STOP internal stop button Stop bits Stopping logging Storage STORED DATA s trigger Sunlight effects on logger Supplementary card Switch 15 30 50 60 baud rate selector DIP power supply selector R PRT t function tables resident sensor linearisation tables Technical support Temperature effects on logger performance Terminal compartment assembly for field installation Terminal mode Terms and Conditions of Sale Thermistor on board cold junction Thermistor tables Thermocouple in field installations tables thermocouple errors Thermsistor on board cold junction Time TIMED data Timed data TIMED RAM TRIG 61 62 data RAM Troubleshooting Printer Voltage common mode divider resistor divider resistors excitation normal mode source on LFW1 Voltage measurement accuracy differential differential using LFW1 Index 60 115 120 21 21 29 50 29 57 21 23 55 6
178. tance measurements Decide whether a resistance offset is required and whether you are going to fit your own offset resistor or use the factory set value of 107 79Q for temperature measurements in the range 20 to 60 C using PT100 sensors R PRT switch and jumper L1 e No offset R PRT switch set to R e Factory set offset R PRT switch set to PRT jumper L1 in 20C position e Alternative offset R PRT switch set to PRT jumper L1 in R position See Calibration of resistance offset below for further instructions Calibration of resistance offset Jumper L1 selects either the factory set offset value for a PT100 at 20 C or a value of your choice Preparation factory set offset To recalibrate the card for a 20 C PT100 offset e Ensure that jumper L1 is fitted in the PRT position as illustrated opposite e Connect a 107 79 calibration resistance to one of the LFW1 channels using the 4 wire connection scheme and program this test channel with the sensor code PT4 Do not use the sensor codes PRT or PT3 Preparation alternative offset To set up a resistance offset value of your choice e Move the jumper L1 to the R4 position the card is supplied with the jumper in the PRT position as illustrated in Figure 9 Page 76 DL2e Hardware Reference Hardware Reference Voltage source adjustment Current limiting LED indicator OFFSET trimmer Jumper L1 20 C trimmer Resistor
179. tch R PRT switch set to R 4 set to PRT RTRT eer resistor R4 PRT position fitted Figure 26 Sensor connections 4 wire resistance DL2e Hardware Reference Page 107 Sensors and Input Cards Hardware Reference Selecting a suitable excitation current Selecting a suitable excitation current The logger measures resistance by passing a selected excitation current through the unknown resistance and measuring the resulting voltage Normally you should choose the largest excitation current that accommodates the maximum resistance to be measured Excitation current Standard sensor type sso iosko iose 1 05Ma The main exception to this rule is that the 2000y A excitation current is unsuitable for use with LAC1 in 30 ch mode You should also consider the following Heating effects The heating effect of the excitation current on resistive temperature sensors is only a problem with miniature sensors if logging at 1s intervals or using READ with the 2000u A excitation current The factors to consider are e Power dissipation PR i e proportional to the square of excitation current e Duration typically excitation current will be passed only for the duration of an analogue reading say 0 1s Auto ranging may occasionally cause more than one reading as the logger changes range Using READ applies excitation current continuously to that sensor e Thermal mass of the sensor e Ability of the sensor to dissipate heat t
180. tential earth loop completion and could cause intermittent errors coinciding with connecting a computer for communication Common mode voltages In differential voltage measurements neither of the logger s input terminals is directly connected to the logger s earth The logger measures the difference between the voltages on its and input terminals both of which float relative to the logger s earth For example the input voltages on the logger s and terminals could be 1 6V and 0 9V respectively relative to the logger s earth The logger would then measure a normal mode voltage of 0 7V The common mode voltage in this example is 0 9V 1 6V 2 1 25V Common mode range The logger s common mode range is the range of common mode voltage over which its full accuracy specification applies The value of the logger s common mode range depends on the relative polarities of the common mode and normal mode voltages e same polarity 2V e opposite polarities 1 05V To guarantee the better common mode performance i e where common and normal mode voltages are of the same polarity the sensor output must be unipolar and connected such that the voltage potential at the logger s input is further from the logger s earth potential than its input For a negative common mode voltage this means that the logger s input should be more negative than its input For sensors with a bipolar output i
181. ter or logger may have a faulty RS232 port Check your cable wiring particularly connections to the logger s TXD and GND 25 pin connector pins 1 2 7 or 9 pin connector pins 3 and 5 Your computer or logger may have a faulty RS232 port Check the terminal program s serial port settings If using HyperTerminal select the Properties command File menu but note that if you want to change the settings you must exit and re start HyperTerminal before the new settings take effect Check the logger s communication parameters settings see Communication parameters on page 50 Put logger back into echo test mode see Error Reference source not found on page Error Bookmark not defined Note that you can change the logger s communication parameters without exiting echo test mode To exit the logger s echo test mode press any of the logger s keys Other causes of communication problems Long cables particularly if screened may be unable to sustain high baud rates Try using a lower baud rate Cables installed in electrically noisy environments may be affected by electrical interference Try using screened cable in which case you may also need to use a lower baud rate DL2e Hardware Reference Hardware Reference DL2e Logger Hardware Field installation Field installation This section explains how to make the DL2e logger secure and weatherproof for operation in the field Temperature The logger
182. tery or rechargeable battery pack type LBK1 see following page e Mains DC power supplies such as are commonly used for powering portable radios These power supplies are normally fully isolated which is desirable If not you may need to take additional care when connecting sensors to avoid earth loops see Earth loops on page 95 e Solar power systems a system is available from Delta T please enquire Power supply connections A flying lead is supplied in the Spares and Accessories pack Use it to make up a suitable cable Flying lead Power supply DL2e Hardware Reference RE Set the power supply selector switch to EXTL see Figure 2 Main circuit board layout and plug the cable into the external power supply socket see fig 12 3 on page 46 It is advisable to keep a good set of internal batteries fitted in the logger The logger will draw power from whichever source internal or external has the higher voltage This means that if the external power supply fails or is disconnected e g to charge an external battery pack the logger will continue to operate from its internal batteries Power supply failure Low battery above explains the action taken by the logger when a power supply failure occurs Page 43 DL2e Logger Hardware Hardware Reference Power supplies WARNINGS Do not connect external power supplies of greater than 15V Damage to the logger may result When more than one battery i
183. the logger s case e Hold down the COLD BOOT and STOP buttons on the main circuit board see Figure 2 Main circuit board layout and then gt if the logger is asleep also press WAKE on the logger s keypad gt ifthe logger is already awake also press the RESET button on the logger s main circuit board see Figure 2 e The message coldbooting appears on the logger s display followed by a sequence of reports as the logger checks RAM chips installs a DEFAULT logging program described in Tutorial Lesson 3 in the Getting Started manual and goes to sleep Ensure that the sequence of reports above does occur Any other type of message indicates that the logger is not in fact coldbooting Note that the logger also coldboots if the logger wakes for any reason while the COLD BOOT and STOP buttons are held down In extreme circumstances you may have to remove all power from the logger before coldbooting Disconnect any external power supply remove the logger s internal batteries gently lift the spring terminal from the top of the lithium cell see Lithium cell on page 42 with a fingernail and hold for 10 seconds Replace the logger s batteries and coldboot as described above Page 15 About the DL2e Logger Hardware Reference Resetting the logger Warm reset A warm reset puts the logger to sleep without destroying any information in the logger s memory data configu
184. tion resistor excitation voltage full half integral excitation quarter Bridge measurement Bridge measurements Bytecount Cable communication logger computer logger printer Cable resistance compensating for error effect on PT100 accuracy effect on thermistor accuracy minimising error Calibration bridge resistance offset shunt resistor voltage divider cards and on board channels Channel counter event trigger frequency on board digital relay Checksum Chips installing Clock setting the logger s CLR event trigger Cold junction compensation on board thermistor Cold junction compensation Coldboot Collecting data Common mode range voltage Communication cable diagnosing faults parameters Computers amp Software DL2e Hardware Reference 24 26 41 41 55 19 41 42 19 46 33 50 50 62 89 109 109 96 96 109 96 109 109 109 63 109 75 109 36 51 52 52 101 104 132 129 63 57 110 76 98 92 65 22 23 22 115 121 36 49 18 23 133 134 101 129 134 15 30 96 96 51 53 33 50 142 config n configuration Configuration DEFAULT Contact Delta T Contrast adjustment Counter resolution Counter card DLC1 Counter input Counting at high frequencies Current excitation measurement Current consumption Data collection erasing erasing from the logger s memory event triggered follow on integrity check starting timed TIMED TRIG 61
185. to start logging was issued It is the date and time of a key press if logging has been started from the keypad or a command issued by means of the PC and not the precise date and time of the first logged data e For an immediate start either using the PC or the keypad there is a short delay between issuing the instruction to start and the first logged data the reported time may be up to 2 seconds earlier than the time of the first logged data e Ifthe logger is set to start at a pre set time or set for a triggered start there is generally a longer time delay between issuing the instruction to start logging and the first logged data Standing by This message indicates that the logger is not yet logging and contains no stored data from a previous logging session Page 20 DL2e Hardware Reference Hardware Reference Interrogating the DL2e logger Logger status Logging stopped Shows the date and time when logging stopped automatically as a result of its memory filling up or detection of a battery failure see Low battery on page 41 or was terminated from the keypad or PC This may not necessarily be the same as the time and date of the last logged reading RAM STATUS and STORED DATA The logger s memory may be partitioned into up to three independent areas or datasets One area can be set aside for timed data i e data stored at the regular time intervals specified in the logging program Two areas can be s
186. ts of a sequence of messages each of which is displayed for approximately two seconds It can be curtailed at any point by pressing any key DL2e Hardware Reference Page 21 Interrogating the DL2e logger Hardware Reference Sensors status Sensors status What the Sensors status provides This shows the current status of all channels that have been programmed as sensors It can be displayed on your PC in the Sensors panel of the DL2 Control Panel or on the logger s Front Panel display using the keypad READ function The DL2 Control Panel displays a single value for each channel The READ function continuously updates the displayed value for a single channel allowing sensor connections to be conveniently tested Relay channels can be exercised and event trigger channels can be tested prior to starting logging This information is independent of logging and can be obtained before or while logging with no interference to logged data Each channel is identified by a number label and sensor code for input channels or by a channel function for other non input types of channel Input channels The READ button on the Front Panel or the Sensors panel in the DL2 Control Panel either gives an instantaneous reading in engineering units or it gives an error message if appropriate See also Error status on page 24 for interpretation of error messages and the additional notes below for counter and frequency channels Counter channels If
187. uple s output voltage depends on the pair of metals used and is roughly proportional to the temperature difference between the thermocouple junction and a cold junction Thermocouple cable is made of the thermocouple materials and the cold junction is the point at which the thermocouple cable terminates in a connection to measuring instrument or a junction box To obtain an absolute temperature reading the temperature of the cold junction has to be measured and added to the temperature difference derived from the thermocouple voltage The logger can perform this calculation which is known as cold junction compensation or cold junction referencing The logger s terminal panel is designed to be isothermal i e all terminals held at the same temperature It has a thermistor mounted on it to measure its temperature The thermistor can be optionally switched into channel to provide a cold junction temperature for thermocouple measurements Thermocouples are small and rugged some capable of measuring temperatures in excess of 1000 C Because they are derived from voltages thermocouple measurements are not adversely affected by cable resistance but long lengths of unscreened cable may pick up electrical noise which can cause errors Disadvantages are that the sensors themselves are not very accurate see below and additional errors arise from measurement of the cold junction temperature Their output for small temperature dif
188. urs if e On analogue channels the logger s full scale input range of 2 096 Volts has been exceeded for resistance channels this is equivalent to 1048 kQ 104 8 kQ 10 48 KQ and 1048 Q for excitation currents of 2 20 200 2000 uA respectively e On counter channels a count of 65472 has been exceeded e On averaged channels the accumulated total of readings within the averaging period has exceeded the logger s arithmetical capacity 2x10 uV or for non linear sensors 2 x 10 engineering units This is reported as ave too large in malfunction reports e For non linear sensors the input falls outside the linearisation table This is reported as outside table in malfunction reports e A valid cold junction temperature is not available for a thermocouple channel that requires a cold junction reference This is reported as bad cold jn in malfunction reports Noisy The logger will not autorange both up and down during a single reading It records a value in the less sensitive range and flags the reading as noisy Outside limit Upper and lower limits for valid readings can be set to any reasonable level and will usually be the most sensitive test for malfunction see Valid Range in the on line Help Page 25 Interrogating the DL2e logger Hardware Reference Error status Outside limits readings are reported as outside limit in malfunction reports and as o s limits in Channel Reports Over runs Over runs occur when st
189. vices by fitting jumpers to the terminal panel see Relay channels on page 121 The power supply selector link The location of the power supply selector link is shown opposite Set the switch to e INTL to power the logger from its internal batteries e EXTL to use an external power supply The internal batteries are still available as a backup source of power in the event of the external power supply being interrupted or dropping significantly below the internal battery voltage The EXTL setting is not recommended if the internal batteries are to be used as the only source of power the voltage available for powering the logger is reduced by a diode drop around 0 6 V from the actual battery voltage and the useful battery life is reduced by 40 Internal battery operation Battery life At 20 C a new set of alkaline AA cells typically provides enough power for e the logger to take about 500 000 typical voltage readings If using data compression the number of stored readings will be much less than this Non linear channels thermocouples in particular and fast changing channels with auto ranging are read at a slower rate and will give proportionally fewer readings from a set of batteries or e year of sleeping activity or e 24 hours waking activity i e keypad use or communicating with a computer f The Logger panel of the DL2 Control Panel displays the battery voltage and an ss estimate of battery
190. ype Fenwal UUA32I2 on ch 62 event haan i 5 ing tebie Thermistor 2K type Fenwal UUA32J2 on ch 62 event Ara ie Vee Thermistor 2K type Fenwal UUA32J2 on ch 62 event aan i anene Thermistor 2K type Fenwal UUA32N2 on ch 62 event a ye anene E E 62 Trigger Data Trigger 1 repeat s On board relay channels D O Warmup 1s every 5s E i Control Output when ch 1 Chan01 gt 20 00000 deg C Figure 38 relay and trigger channel wiring for intermittent logging example DL2e Hardware Reference Page 127 Sensors and Input Cards Thermistors Thermistors Hardware Reference Thermistors are low cost resistive sensors suitable for general purpose temperature measurements Thermistors are manufactured from semiconducting material They have a negative temperature coefficient which means that their resistance decreases with rising temperature The main point in their favour is that they respond to temperature changes with a relatively large change in resistance a typical temperature coefficient at 25 C is 4 5 per C and this makes them easy to use for temperature measurements without resorting to specialist measurement techniques A disadvantage of thermistors is that their response to temperature is highly non linear and linearisation tables spanning wide temperature ranges may contain significant errors This is not an issue for environmental temperature measurements in the ra

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