ADC-20/ADC-24 User's Guide
Contents
1. ADC 20 ADC 24 High Resolution Data Loggers User s Guide adc20 en 3 Copyright O 2005 2010 Pico Technology Ltd All rights reserved I Contents Contents fl AEF OC 8 oii To Ja E EE E RD NR AR SR aa 1 1 Overview CRsmaniasiassionaias cbebe oco ances cetcledecscodecsdacdaddepseuevoss antas lona Ton cs ds antas dean on d do cias menda nooo nds race sis acta dis 1 2 Notices RNET 2 1 Safety warning RO 2 2 Legal information iii A EE A AAA aiii 3 3CE noti e aeaee EAEE an ena GAR aa Las AU EEN dressere GARRO aU cag EGO ESA O ad CNO STA U AGUA U AAA AGUAS Si ENEE 3 AFCC notice ustismesiadoossssddiamodaliasscuicaeno tooo coat sou a cacho aS Teaterets 3 Trademarks asim his dote radio de magia ra een 4 6 Updates EEE SP ET BEE nato iii 4 7 Support and refunds or0vor0nonrnnnnnnnnnnnvnnnnnnnnnnnnnnvnnnnnnnnnnnnanenanenansnnnnnasnnnsnnnsnnnsnnnsnannnannnnsnnnsnanennnsnnnsnasnnasernsnnne 4 8 Company details ran nnnsnnnnnnnnnannnnnnansnansnansnansnannnanennsnnnsnnnsnnnsnnnnnasnnnsnnnsnnnsnnnsnnnenasnnnsenssvnne 4 Gene A A a a apa 5 1 Installing AETLI T E IEE A E NE siena ton ti isenta ddoni incisos esa doada to cuia d dani ne ani sadias Toda uenedsadeded cbeeuaesseiaciesess 5 2 Connecting the data logger sscssssssssessssesessssesesssessenssesseesessessssssessessseaesessesseessessseeseseessesssesseseessesssnseeaeees 5 3 Starting PicoLog PIERRE ORAR PREPARE REPARE RS PRE D A RD RE DRA SENT 7 4 About theUNit serrent E ia ara aiii 102. FUN Je 43 a o EE SEE A EEE 45 Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en Introduction 1 1 Introduction Overview The ADC 20 and ADC 24 High Resolution Data Loggers are multichannel high accuracy USB data loggers for use with PCs They require no external power supply and take up no expansion slots They come complete with PicoLog a program offering all the features of a stand alone data logger You should have the following items in your ADC 20 or ADC 24 package ADC 20 or ADC 24 High Resolution Data Logger Pico Technology Software and Reference CD Installation Guide The CD includes driver software that enables you to write your own programs to control the data logger using a variety of popular programming languages The hardware and software are compatible with Microsoft Windows XP SP2 or later Optional accessories PP310 ADC 20 ADC 24 Terminal Board adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 2 2 1 Notices Safety warning We strongly recommend that you read the general safety information below before using your product for the first time If the equipment is not used in the manner specified then the protection provided may be impaired This could result in damage to your computer and or injury to yourself or others Maximum input range The ADC 20 and ADC 24 are designed to measure voltages in
3. Tintroducton usa E RED E E AO EO OC 10 2 Specifications srrerrrnrnnnnnnnnnnnnnnnenanennnsnnnnnannrnsnnnsnnnsnannnannnnsnnnsnanenanenannnasnnnsnnnsnnnsnnnnnasnrnsnansnnnsnanenannnasenssenne 10 3 Analog COTATI COOK AE A fake as bes bres A enn aaret 12 4 Noise free resolution and conversion time ccsssccssccssccesccescceecccesccssceeecccesccescceesccesceesceeeseeesceeseeeeseeesceees 12 5 ADC 20 ADC 24 terminal board ss t crac AAA RAEE A rin 13 BLED Miri A AAA iia 13 A AAA A 14 1 Recording A AAN 14 2 Windowsdriver atascos Ruas cia nina nto asda ida iii 14 3 Scaling 4 Driver functions 1 HRD CloseUnit o rr alii acabe 16 2 HRDLCollectSingleValueAsyne coca 17 3 HRDLGetMinMaxAdcCounts cc reeeerrererertaerencarerencacarencararencacenencanes 18 4 HRDLGetNumberOfEnabledChannels rnes ree reeerseeereseveeersesesseccssesnssensnsscassnnsscnnsennnsonssessnscsnesensesnsosennsensesenive 19 5 HRDLGetSingleValue e nens 20 6 HRDLGetSingleValueAsync nenes 21 7 HRDLGetTimesAndValues conca 23 8 HRDLGetUnitinfo eeeeveeeeeseeeseesesesensenrssnsenessnsenensnsenearnsenennsenensnsenensnsrnenensnsenensnsensnsssenensnsenensnsenensnsenessnsenensn 24 9 HRDLGetValues _wrrvvssevstsestsssseeessscscnscscncsncscncnscscscescnesenesseacseencneneensacaesnensseensnesenesnssesssassesessaeseeasasseesaeaseneases 26 A RS 27 11 HRDLOpenUnitAsync jpepeeeeeeeeeeeeeeeeeeeeeeeeemeeeeeemeeeeeisrsrssseersrerssersrsrereresseseerererseseessesseseeeseseseseseses
4. 35 HRDLSetMains 36 HRDLStop 37 Humidity range 10 Immunity 3 Input channels 10 Input connector 10 Input impedance 10 Input isolation 10 Input voltage ranges 2 10 Installing software 5 Interference 3 Isolation 10 Error codes 24 L EKUSI 729 LabVIEW 39 LED 13 Legal information 3 adc20 en Copyright 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 46 Liability 3 Low Voltage Directive 3 M Mains voltages 2 Manual 14 Maximum input range 2 Mission critical applications 3 N Noise rejection 10 Noise free resolution 12 O Offset error 10 Overview 1 Overvoltage protection 2 10 P PC connection 10 Phone number 4 PicoLog 1 7 10 installing 5 Power outputs 10 Power supply 10 Programming languages 38 Agilent VEE 39 C 38 C 38 Delphi 38 Excel macros 39 LabVIEW 39 Visual Basic 39 R Recording methods 14 42 block 40 single value blocking 42 single value non blocking 42 streaming 40 41 windowed 41 Reference output 10 Repairs 2 Resolution 10 noise free 10 S Safety warning 2 Scaling 14 Sequence of calls 40 Settings error codes 24 Single value blocking recording 42 Single value non blocking recording 42 Software installing 5 Specifications 10 Streaming 40 Streaming recording 41 Support 4 T Telephone number 4 Temperature range 10 Terminal board 12 Trademarks 4 U Upgrades 4 Usage 3 V Viruses 3 Visual Basic 39 Volt
5. If the range is not valid the function will return 0 The time interval in which the sample should be converted See HRDLSetInterval for possible values If the conversion time is invalid the function will fail and return 0 The type of voltage to be measured O differential nonzero single ended overflow Pointer to a bit field that indicates when the voltage on a channel has exceeded the upper or lower limits Bit O Channel 1 Bit 15 Channel 16 value Pointer to a long where the ADC value will be written Returns 1 if a valid handle is passed and settings are correct 0 if not If the function fails call HRDLGetUnitinfo with info HRDL ERROR 7 to obtain the error code If the error code is HRDL_SETTINGS 5 then call HRDLGetUnitlnfo again with info HRDL SETTINGS ERROR 8 to determine the settings error Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 21 Programmer s reference 5 4 6 HRDLGetSingleValueAsync short HRDLGetSingleValueAsync short handle long value short overflow This function retrieves the reading when the HRDLCollectSingleValueAsync has been called Arguments handle Handle returned by HRDLOpenUnit value Pointer to a long where the ADC value will be written overflow Pointer to a value that indicates when the voltage on a channel has exceeded the upper or lower limits Bit O Channel 1 Bit 15 Channel 16 Returns 1 if a
6. Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 14 5 5 1 5 2 5 3 Programmer s reference Recording methods The ADC 20 ADC 24 driver provides three methods of recording data All these methods support USB1 1 amp Streaming The driver constantly polls the device and samples are placed in a buffer until retrieved by your application Precise sample timing is controlled by the unit amp Single Value blocking You make a single request for a sample blocking the calling thread and when the sample has been received the driver returns the value to your application amp Single Value non blocking You make a single request for a sample without blocking the calling thread and when the sample has been received the driver returns the value to your application Windows driver Once you have installed the software the Drivers Win32 subdirectory will contain a demo program HRDL c that shows exactly how to drive the data logger and a driver PicoHRDL dll It also contains a copy of this manual as a PDF file ADC20044 PDF PicoHRDL d11 is a Windows Dynamic Link Library DLL which can be used with C C Delphi Visual Basic National Instruments LabVIEW and Agilent VEE programs It can also be used with programs like Microsoft Excel where the macro language is a form of Visual Basic More than one application can access the Windows DLL at the same time as long as the applications do not ch
7. The routines described here were tested on Windows XP using LabVIEW 8 0 We can provide older versions from 6 1 and 7 1 upon request While it is possible to access all of the driver routines described earlier it is easier to use the special LabVIEW access routine The HRDL vi library in the installation directory shows how to access this routine To use this routine copy PicoHRDL dil to your working directory You can use one of the sub VIs supplied for each of the channels that you wish to measure The VI accepts the handle and the channel 1 to 8 for ADC 20 1 to 16 for ADC 24 only odd numbered channels in single ended mode and returns the voltage in millivolts 5 5 5 Visual Basic Version 6 The installation directory contains the following files O HRDL VBP O HRDL BAS O HRDL FRM 5 5 6 Agilent VEE The example routine HRDL vee is included in the SDK It was tested using Agilent VEE version 7 5 on Windows XP The example shows how to collect readings continuously from the data logger VEE also requires a header file HRDL VH This file is installed with your Pico software adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 40 5 6 5 6 1 5 6 1 1 Sequence of calls and data flow The C sample program HRDL c demonstrates the use of all the functions of the API driver and includes examples showing each mode of operation Streaming recording methods Collecting a block of data Th
8. function fails call HRDLGetUnitlnfo with info HRDL SETTINGS ERRORS for the specific settings error Conversion times HRDL 60MS 0 adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 36 5 4 18 HRDLSetMains short HRDLSetMains short handle short sixtyHertz This function configures the mains noise rejection setting Rejection takes effect the next time sampling occurs Arguments handle Handle returned by HRDLOpenUnit sixtyHertz Specifies whether 50 Hz or 60 Hz noise rejection is applied O reject 50Hz lt gt 0 reject 60 Hz Returns O if failed 1 if successful Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 37 Programmer s reference 5 4 19 HRDLStop void HRDLStop short handle This function stops the device when streaming Arguments handle Handle returned by HRDLOpenUnit adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 38 5 5 Programming languages The software installed with your ADC 20 or ADC 24 includes examples for the following programming languages The example programs are installed in the Examples ADC20 subdirectory of your PicoLog installation C and C C The C example program is a generic windows application it does not use Borland AppExpert or Microsoft AppWizard To compile the program create a new project for an applic
9. the range 2 5 volts but are protected against overvoltages of 30 volts Any voltages outside the overvoltage protection range may cause permanent damage to the unit Mains voltages Pico products are not designed for use with mains voltages Safety grounding The ground of every product is connected directly to the ground of your computer via the interconnecting cable provided This is done to minimise interference If the PC especially laptops is not grounded reading stability cannot be guaranteed and it may be necessary to manually ground the equipment As with most data loggers you should take care to avoid connecting the inputs of the product to any equipment which may be at an unsuitable voltage If in doubt use a meter to check that there is no hazardous AC or DC voltage Failure to check may cause damage to the product and or computer and could cause injury to yourself or others You should assume that the product does not have a protective safety earth Incorrect configuration and or use on voltages outside the maximum input range can be hazardous Repairs The unit contains no user serviceable parts repair or calibration of the unit requires specialised test equipment and must be performed by Pico Technology Limited or their authorised distributors Copyright 2005 2010 Pico Technology Ltd All rights reserved adc20 en Notices 2 2 2 3 2 4 Legal information The material contained in this release i
10. unless the function returns true progress Pointer to a short to which the percentage progress is to be written 100 implies that the open operation is complete Returns 0 if open operation is still in progress 1 if the open operation is complete adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 30 5 4 13 HRDLReady short HRDLReady short handle This function indicates when the readings are ready to be retrieved from the driver Arguments handle Handle returned by HRDLOpenUnit Returns O if not ready or failed 1 if ready Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 31 Programmer s reference 5 4 14 HRDLRun short HRDLRun short handle long nValues short method This function starts the device sampling and storing the samples in the driver s buffer See Streaming recording meth for help on using this function Arguments handle Handle returned by HRDLOpenUnit nValues Number of samples to collect for each active channel method Sampling method This should be one of the values listed below Returns O if failed 1 if successful Sampling methods ollect a single block and stop BM lt 1 ollect a sequence of overlapping blocks 2 BM STREAM ollect a continuous stream of data adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s
11. used to return the maximum ADC count available for the unit referred to by handle channel Channel number for which maximum and minimum ADC count are required Returns 1 if a valid handle is passed 0 if not Copyright 2005 2010 Pico Technology Ltd All rights reserved adc20 en 19 Programmer s reference 5 4 4 HRDLGetNumberOfEnabledChannels short HRDLGetNumberOfEnabledChannels short handle short nEnabledChannels This function returns the number of analog channels enabled Arguments handle Handle returned by HRDLOpenUnit nEnabledChannels Pointer to a short where the number of channels enabled will be written Returns 1 if a valid handle is passed 0 if not adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 20 5 4 5 HRDLGetSingleValue short HRDLGetSingleValue short handle short channel short range short conversionTime short sing eEnded short overflow long value This function takes one sample for the specified channel at the selected voltage range and conversion time Arguments handle channel range conversionTime singleEnded Handle returned by HRDLOpenUnit The channel number to convert ADC 20 1 to 8 ADC 24 1 to 16 If the channel is not valid then the function will fail and return O The voltage range to be used See HRDLSetAnaloginChannel for possible values
12. 3 Point to New settings PLW Recorder New settings We 4 At the Recording dialog click OK Recording xi sop ties y E TT A AL 5 At the Sampling Rate dialog click OK Sampling Rate xi x 00 As may as poso 7 adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 8 6 In the Converter details dialog set the Converter type to High Resolution Data Logger The device type and serial number should appear in the USB Devices list and the USB enumeration progress indicator should gradually move towards 100 If the progress indicator does not start moving disconnect and reconnect the unit and then press Refresh Converter details x Converter type High Resolution Data Logger y Port v Cancel USB Devices Hel p ADC 20 154372 Status USB enumeration progress A Refresh 7 Click OK 8 At the ADC 20 or ADC 24 channels dialog double click on Channel 1 ADC 20 Channels xj Name Status Range Single Ended Conversion Time Channel 1 Available Channel 2 Available Edit Channel 3 Available Channel 4 Available Disable Channel 5 Available Channel 6 Available Cancel Channel 7 Available Channel 8 Available Mains frequency 50Hz C 60Hz Help 9 At the Edit ADC 20 or ADC 24 Channel dialog click OK Edit ADC 20 Channel Xi Name Channel 1 Conversion Time m
13. ADC 20 channel 8 If one or more digital channels are set as inputs then the first sample contains the digital channels Digital inputs The digital channels are represented by a binary bit pattern with O representing off and 1 representing on Digital input 1 is in bit 0 Copyright 2005 2010 Pico Technology Ltd All rights reserved adc20 en 27 Programmer s reference 5 4 10 HRDLOpenUnit short HRDLOpenUnit void This function opens a data logger The API driver can support up to four units Arguments None Returns 1 if the unit fails to open 0 if no unit is found gt 1 handle to the device opened adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 28 5 4 11 HRDLOpenUnitAsync short HRDLOpenUnitAsync void Opens a data logger without blocking the calling thread Arguments None Returns 0 if there is already an open operation in progress 1 if the open operation has been initiated Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 29 Programmer s reference 5 4 12 HRDLOpenUnitProgress short HRDLOpenUnitProgress short handle short progress Checks the progress of an asynchronous open operation Arguments handle Pointer to a short where the unit handle is to be written 1 if the unit fails to open O if no unit is found gt 0 a handle to the device opened this handle is not valid
14. ADC 24 User s Guide 2 5 2 6 2 7 2 8 Trademarks Pico Technology Limited and PicoLog are trademarks of Pico Technology Limited registered in the United Kingdom and other countries Pico Technology acknowledges the following product names as trademarks of their respective owners Windows Excel Visual Basic LabVIEW Agilent VEE Delphi Updates We provide upgrades free of charge from our web site We reserve the right to charge for updates or replacements sent out on physical media Support and refunds If you are dissatisfied with the performance of this software please contact our technical support staff who will try to fix the problem within a reasonable time If you are still dissatisfied please return the product and software to your supplier within 14 days of purchase for a full refund Company details Address Pico Technology James House Colmworth Business Park St Neots Cambridgeshire PE19 8YP United Kingdom Phone 44 0 1480 396395 Fax 44 0 1480 396296 Email Technical Support support picotech com Sales sales picotech com Web site www picotech com Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en Getting started 3 1 3 2 Getting started Installing the software Before you connect the ADC 20 or ADC 24 to your computer for the first time you must install the software supplied on the CD Insert the Software and Reference CD then follow the I
15. DLL is a file containing a collection of Windows functions designed to perform a specific class of operations Driver A driver is a computer program that acts as an interface generally between a hardware component and a computer system the hardware in this case being the data logger EMC Electromagnetic compatibility The ability of a device to operate in proximity with other devices without causing or suffering undue interference from electromagnetic fields or conducted electrical noise Gain error Gain error is the worst deviation of a measurement from the true value measured over the whole input range and expressed as a percentage Galvanic isolation A barrier between two parts of an electrical circuit that prevents noise and voltage offsets in one part from affecting the other part Input impedance This is the impedance of the input channel of the data logger Impedance is the ratio of the voltage across the input to the current flowing through it and at low frequencies can be considered as a pure resistance The larger the impedance the more accurate the measurement Input voltage range The input voltage range is the range of voltages that an analog channel can convert without an overload error The maximum input voltage range of the ADC 20 and ADC 24 is therefore 2 5 V to 2 5V Furthermore you should not inject voltages outside the range 5 V to 5 V as this can cause measurement errors on all channels You will not damage
16. Guide 32 5 4 15 HRDLSetAnaloglnChannel short HRDLSetAnalogInChannel short handle short channel short enabled short range short singleEnded This function enables or disables the selected analog channel If you wish to enable an odd numbered channel in differential mode you must first make sure that its corresponding even numbered channel is disabled For example to set channel 1 to differential mode first ensure that channel 2 is disabled Arguments handle Handle returned by HRDLOpenUnit channel The channel that will be enabled or disabled ADC 20 1 to 8 ADC 24 1 to 16 enabled Sets the channel active or dormant O dormant lt gt 0 active range The voltage range to be used during sampling Applies only to selected channel See Voltage ranges below singleEnded Non zero to measure a single ended voltage Zero for a differential voltage Returns O if failed 1 if successful If the function fails call HRDLGetUnitlnfo with info HRDL SETTINGS ERROR 8 to obtain the specific settings error Voltage ranges Availabilit Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 33 Programmer s reference 5 4 16 HRDLSetDigitallOChannel ADC 24 only short HRDLSetDigitalIOChannel short handle short directionOut short digitalOutPinState short enabledDigitalIn Sets up the digital input output channels If the direction is o
17. ITAL IO CHANNEL 4 8 8 amp To set only digital channel 3 high digitalOutPinState HRDL DIGITAL IO CHANNEL 3 4 4 amp To tum both digital channels 3 and 4 on digitalOutPinState HRDL_DIGITAL_IO_CHANNEL_4 8 HRDL_DIGITAL_IO_CHANNEL_3 4 12 Example bit patterns for directionOut parameter a Pt E Eta E Pattern hannel 4 Channel 3 Channel 2 Channel 1 0 12 100 13 1101 The above is a selection of the 16 different options available for the direction0ut parameter When a digital channel has been selected as an output it can then be set on or off with the digitalOutputPinState parameter again using binary bit patterns to represent the different digital channels The default setting for the digital channels is output off Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 35 Programmer s reference 5 4 17 HRDLSetInterval short HRDLSetInterval short handle long sampleInterval ms short conversionTime This sets the sampling time interval The number of channels active must be able to convert within the specified interval Arguments handle Handle returned by HRDLOpenUnit samplelnterval_ms Time interval in milliseconds within which all conversions must take place before the next set of conversions starts conversionTime The amount of time given to one channel s conversion This must be one of the constants below Returns O if failed 1 if successful If the
18. ROR he unit is functioning correctl HRDL KERNEL DRIVER 1 he picopp sys file is to old to support his product HBDL NOT FOUND 2 JNo data logger could be found ERDI CONFIG FAIL 3 Unableto download firmware HRDL HRDL ERROR OS NOT SUPPORTED 4 his device he maximum number of units allowed are already open Settings Error Codes when info HRDL SETTINGS ERROR Error Code Description SE CONVERSION TIME OUT OF RANGE 0 he conversion time parameter is out of range OUT OF RANGI E TOO SLOW he conversion time chosen is not fast enough to convert all channels within the ample interval EL_NOT_AVAILABLI he channel being set is valid but not urrently available device device is not valid SE_INVALID_PARAMETER 6 One or more parameters are invalid SE CONVERSION IN PROGRESS 7 A conversion is in progress for a single asynchronous operation SE COMMUNICATION FAILED 3 ES SE OK 9 All settings have been completed Successfull Settings adc20 en Copyright 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 26 5 4 9 HRDLGetValues long HRDLGetValues short handle long values short overflow long noOfValues This function returns the requested number of samples for each enabled channel so the s
19. age ranges 32 W Website 4 Weight 10 Windowed recording 41 Windows 1 Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 47 adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved Pico Technology James House Colmworth Business Park ST NEOTS Cambridgeshire PE19 8YP UK Tel 44 0 1480 396 395 Fax 44 0 1480 396 296 www picotech com adc20 en 3 5 1 10 Copyright O 2005 2010 Pico Technology Ltd All rights reserved
20. alog and digital grounds are not connected together inside the unit You should not connect them together externally as this would degrade the accuracy of the unit Note 6 For easy connection to the DB25 connector we recommend that you use the ADC 20 ADC 24 terminal board 4 4 Noise free resolution and conversion time The table below shows the number of noise free bits of resolution for the full range of conversion times Conversion Voltage range time amp Noise free resolution bits per channel 39 mv 78 mv 156 mv 313 mv 625 mv 1250 mv 2500 mv A ADC 24 only __________ ADC 20andADC 24 Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 13 About the unit 4 5 4 6 ADC 20 ADC 24 terminal board For easy connection to the DB25 connector we recommend that you use the ADC 20 ADC 24 terminal board part number PP310 This has screw terminals to allow you to connect wires to all of the data logger s inputs and outputs without soldering It also has space for voltage divider resistors a temperature sensor and a quad op amp LED The ADC 20 and ADC 24 have an LED next to the entry point of the USB cable that you can use to verify that the unit is working The LED flashes whenever the unit is taking readings It also flashes briefly during enumeration the process that PicoLog uses to detect all Pico USB devices plugged in to the computer adc20 en Copyright O 2005 2010
21. ange the settings for channels that they are not using The driver supports all Windows operating systems from Windows XP onwards Scaling To convert from ADC values to volts first obtain the minimum and maximum ADC values for the selected channel by calling the HRDLGetMinMaxA nts function in the driver Next scale the ADC value to the voltage range you specified when you called HRDLSetAnaloginChannel You can calculate the voltage range programmatically by using Vmax 2500 mV 211 where r is the range constant you supplied to HRDLSetAnaloglnChannel 0 for 2500 mV 1 for 1250 mV and so on Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 15 Programmer s reference 5 4 Driver functions The following sections describe the functions available to an application using the ADC 20 and ADC 24 All functions are C functions using the standard call naming convention __stdca11 and are exported with both decorated and undecorated names Function HRDLCloseUnit HRDLCollectSingleValueAsync HRDLGetMinMaxA nt HRDLGetNumberOfEnabl HRDLGetSingleValue HRDLGetSingleValueAsync HRDLGetTimesAndVal HRDLGetUnitinfo HRDLGetValues HRDLOpenUnit HRDLOpenUnitAsync HRDLOpenUnitProgress HRDLReady HRDLRun HRDLSetAnaloginChannel HRDLSetDigitallOChannel HRDLSetinterval HRDLSetMains HRDLStop hannel Description Shuts down unit Starts t
22. ation containing the following files HRDLGui c graphical user interface or HRDL c console PicoHRDL 1ib Microsoft C or PicoHRDLbe lib for Borland C The following files must be in the same directory HRDL h O PicoHRDL dll resource h required by HRDLGui c amp HRDLGui rc required by HRDLGui c C If HRDL h is included in a C program the PREFO macro expands to extern C this disables name decoration as Microsoft calls it and enables C routines to make calls to the driver routines using C headers Delphi V3 You will need the following files from the SDK amp hrdl dpr a complete program that opens the driver and reads values from channel 1 hrdlfm pas required for streaming or single value data collection O hrdlfm dfm The file hrdl inc contains a set of procedure prototypes that you can include in your own programs Copyright 2005 2010 Pico Technology Ltd All rights reserved adc20 en 39 Programmer s reference 5 5 3 Excel The easiest way to get data into Excel is to use PicoLog for Windows If however you need to do something that is not possible using PicoLog you can use an Excel macro to read in a set of data values The Excel Macro language is similar to Visual Basic Excel 2002 The example 4RDL XLS reads in 100 times and values from channels 1 and 3 at 121 ms for both channels and assigns them to cells B4 C103 The times are stored in cells A4 103 5 5 4 LabVIEW
23. conditions Operating temperature Quoted input accuracy Storage temperature Operating humidity rage humidit Sto Recommended calibration interval nput connector ower suppl ADC 20 None Galvanic up to 30 V AGND and DGND isolated 2 5 V 2 5 mV 2 mA 5 V 1 0 V amp 2 mA 5 V 1 5 V 2 mA 02C to 4529C 202C to 302C 202C to 602C 5 to 80 RH noncondensing 5 to 95 RH noncondensing 1 year USB 1 1 USB 2 0 compatible Cable length approx 4 4 m 13 8 ft DB25 female 100 mA max from USB port 13 5 cm x 18 4 cm x 3 6 cm 5 31 in x 7 24 in x 1 41 in Approx 505 g 17 8 oz adc20 en Copyright 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 12 4 3 Analog connector Analog inputs are connected to the ADC 20 and ADC 24 through the female DB25 connector The connections are as follows 4 Channel8 Channel7 ____ iz_ Khamel7 6 Channel 12 Channel 11 ___ io Channel ll 8g_____ Channel 16 Channel 15 ___p1 Chameli5s______ 9 AnalogGround P2 Digital Ground Digital 1 0 1 Digital 1 0 2 Do Note 1 Channel numbers in brackets apply when the input is set to differential mode Note 2 Channels 9 to 16 exist only on the ADC 24 Note 3 Digital I Os 1 to 4 exist only on the ADC 24 Note 4 Pins 10 and 11 are low current outputs for powering small sensors Do not exceed the current limits given in the Specifications table Note 5 The an
24. d FALSE r test to see if no conversion is in progress if bStartedConversion start the conversion going bStartedConversion HRDLCollectSingleValueAsync handle channel range conversionTime singleEnded bConversionFinished TRUE Copyright 2005 2010 Pico Technology Ltd All rights reserved adc20 en 23 Programmer s reference 5 4 7 HRDLGetTimesAndValues long HRDLGetTimesAndValues short handle long times long values short overflow long noOfValues This function returns the requested number of samples for each enabled channel and the times when the samples were taken so the values array needs to be number of values x number of enabled channels When one or more of the digital IOs are enabled as inputs they count as one additional channel The function informs the user if the voltages for any of the enabled channels have overflowed Arguments handle Handle returned by HRDLOpenUnit times Pointer to a long where times will be written values Pointer to a long where sample values will be written If more than one channel is active the samples are interleaved If digital channels are enabled then they are always the first values See table below for the order in which data are returned overflow Pointer to a short indicating any inputs that have exceeded their maximum voltage range Channels with overvoltages are indicated by a high bit with the LSB indicating cha
25. esesenesene 28 12 HRDLOpenUnitProgress cnc 29 13 HRDLReady A cercanas 30 ASHRDERON A AASEN aia 31 15 HRDLSetAnaloginChannel O 32 adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide ll 16 HRDLSetDigitall OChannel ADC 24 only 33 17 HRDLSetinterval seeseseeseeeeseeseseeneanenennernenseneasessensasessensanersensaversensanersensenersensenersensenersensenersensansrnenennsrnensonsanenee 35 18 HRDLSetMains seeeeeresesesensesesensesesensesesrnsnsenrasesenrasnnenessasenensnsenensnsenensasenensasesensnsesenensnsenensnsenensnsenensnsenensnsener 36 19 HRDLStop rr nenes 37 5 Programming languages sssssssessessessessessensesseeseesessensessensecseeseeseessessensensesseeseeseestensensessecssessessentensensones 38 RO 38 HE 38 Excel 0 Gskkkekank eaveecaes saviaedvaseacaenssneaiinseaanues aja a nake Rank a 39 ESTEN 39 E Visual Basien RR A Aira Std 39 6 Agilent VEE A encore 39 6 Sequence of calls and data flow oooonocnonocnononncnnononncnnononnon canon nonnnon conc riken oE KAKES VESANEN KEKEE no nan Eas S 40 1 Streaming recording methods 00000ssesesssereserssrrsrsrerere reser streets renere rer erste ret ses sense se eee tese esse esse ses eee nesesenenesesenesesesesene 40 2 Single value recording methods sssssssesesssssessrert satses teten teen eneste eneste teen ette teen esse enes esse sees sees ee eeeseeneseneeeeesesesesesenesene 42
26. ghts reserved ADC 20 ADC 24 User s Guide 6 In the Welcome to the New Hardware Found Wizard dialog above click Next gt amp Wait while the wizard installs the software A dialog will appear like the one below Hardware Installation A The software you are installing for this hardware Pico High Resolution Data Logger has not passed Windows Logo testing to verify its compatibility with Windows XP Tell me why this testing is important Continuing your installation of this software may impair or destabilize the correct operation of your system either immediately or in the future Microsoft strongly recommends that you stop this installation now and contact the hardware vendor for software that has passed Windows Logo testing STOP Installation amp Click Continue Anyway amp Continue to wait while the wizard installs the software When instructed click Finish to close the wizard After a few seconds you should see this message j Found New Hardware x Your new hardware is installed and ready to use amp Your ADC 20 or ADC 24 Data Logger is now properly installed Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 7 Getting started 3 3 Starting PicoLog To check that the data logger is working start the PicoLog application as follows 1 Start PicoLog Click the PicoLog icon Ip PicoLog Recorder in your Windows Start menu 2 Click File
27. he unit sampling one value without blocking the calling application s flow Returns the maximum and minimum ADC count available for the device Returns the number of analog channels enabled Takes one sample for the specified channel at the selected voltage range and conversion time Retrieves the reading when the HRDLCollectSingleValueAsync has been called Returns the requested number of time stamped samples for each enabled channel Writes unit information to a character string Returns the requested number of samples for each enabled channel Opens data logger unit Opens unit without blocking the calling thread Checks the progress of an asynchronous open operation Indicates when readings are ready to be collected Starts the device sampling and storing the samples into the driver s buffer Enables or disables the analog channel Sets a digital output or input ADC 24 only Sets the sampling time interval Sets the mains noise rejection frequency Stops the device when streaming adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 16 5 4 1 HRDLCloseUnit short HRDLCloseUnit short handle Shuts down a data logger unit Arguments handle The handle returned by HRDLOpenUnit of the unit being closed Returns 1 if a valid handle is passed 0 if not Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 17 Programmer
28. inputs may be configured as 16 single ended inputs or any combination in between Power and connection to a PC or laptop is through a USB 1 1 or USB 2 0 port Using the supplied PicoLog software you can record monitor and analyse collected data even exporting to third party applications such as Microsoft Excel Specifications ADC 20 ADC 24 OOOO Input channels Differential Configurable up to 4 Configurable up to 8 Single ended Configurable up to 8 Configurable up to 16 onversion time per channel 60 ms 100 ms 180 ms 340 ms 660 ms 1250 mV and 2500 mV 39 mV to 2500 mV esolution oise free resolution vervoltage protection Common mode range Channel to common 1 9 V 39 mV to 1250 mV ranges Channel to common 3 0 V 2500 mV range Common to earth ground 30 V Common mode rejection ratio Channel to common 95 dB d c to 60 Hz Common to earth ground gt 125 dB d c to 60 Hz Noise rejection 1 MQ single ended impedance due to input impedance 0 2 at 2500 mV Offset error 6 uV 39 mV range 7 uV 78 mV range 9 uV 156 mV range 13 uV 313 mV range 20 uV 625 mV range 36 uV 1250 mV range 400 uV 2500 mV range igital I O Output level high Output level low Input level high Input level low Copyright 2005 2010 Pico Technology Ltd All rights reserved adc20 en 11 About the unit solation input to input Isolation input to ground eference output Power outputs Environmental
29. is method collects a single block of data and then stops amp Open the data logger with one of the HRDLOpenUnit calls amp Set mains noise rejection with HRDLSetMains amp Set the analog or and digital channels amp Set the sample interval with HRDLSet nterval amp Start the unit collecting samples by calling HRDLRun with method BM BLOCK amp Loop Repeat Loop until ready HRDLReady amp Collect data with HRDLGetVal amp Repeat from Start the unit SAA Application HRDLSetMains HRDLSetInterval USB RUN STREAMING Data To RT 1 Va Data not collected j Data 7 collected HRDLReady Ao E Status HRDLGetValues Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 41 Programmer s reference 5 6 1 2 Collecting windowed or streaming data This method causes the device to start sampling Samples are stored in the driver s buffer In windowed mode the buffer will always contain the requested number of samples but generally only a subset of these are new data In streaming mode new data are returned continuously amp Open the data logger with one of the HRDLOpenUnit calls amp Set mains noise rejection with HRDLSetMains amp Set the analog or and digital channels amp Set the sample interval with HRDLSetInterval amp Start the unit collecting samples by calling HRDLRun with method BM WINDOW or BM STREAM amp Loo
30. ize of the values array needs to be number of values x number of enabled channels When one or more of the digital lOs are enabled as inputs they count as one additional channel The function informs the user if the voltages of any of the enabled channels have overflowed Arguments handle Returned by HRDL nUnit values Pointer to a long where the sample values are written If more than one channel is active the samples are interleaved If digital channels are enabled then they are always the first value See table below for the order in which data are returned overflow Pointer to a short indicating any inputs that have exceeded their maximum voltage range Channels with overvoltages are indicated by a high bit with the LSB indicating channel 1 and the MSB channel 16 noOfValues The number of samples to collect for each active channel Returns A non zero number if successful indicating the number of values returned or O if the call failed or no values available Ordering of returned data example When two analog channels e g 1 and 5 are enabled and a digital channel is set as an input the data are returned in the following order Sample Not O 1 2 3 4 5 6 T 8 9 10 11 12 13 14 gt n 3 n 2 n Channel DET 5 DIA 5 BEL 3 DIA 3 DILL 5 DE 1 5 1 where n represents the value returned by the function and DI the digital inputs The channels are always ordered from channel 1 up to the maximum channel number ADC 24 channel 16
31. lossary Asynchronous In asynchronous data collection your application requests data from the driver and the driver immediately returns without blocking the application The application must then poll a status function until the data is ready Common mode rejection ratio The ratio by which the data logger attenuates a common mode voltage see below It is defined as CMRR dB 20 log10 Vin Vmeas where CMRR dB is the common mode rejection ratio in decibels Vin is the common mode voltage present at the input and Vmeas is the common mode voltage visible in the measured data Common mode voltage A differential signal fed into the data logger consists of a positive input Vp and a negative input Vn and the logger measures the difference Vdiff Vp Vn between the two inputs This means that any offset in ground potential between the signal source and the data logger adds a constant voltage called the common mode voltage Vcm to both inputs equally so ideally it does not affect Vdiff In practice however the data logger cannot make an accurate measurement if Vcm is too large and even small values of Vcm may affect the reading slightly Data logger A measuring instrument that monitors one or more analog signals samples them at pre programmed intervals then accurately converts the samples to digital data and stores them in memory The ADC 20 and ADC 24 use your PC for storage and display DLL Dynamic Link Library A
32. ments handle Handle to the device from which information is required If an invalid handle is passed the error code from the last unit that failed to open is returned as if info HRDL_ERROR unless info HRDL DRIVER VERSION and then the driver version is returned string Pointer to the character string buffer in the calling function where the unit information string selected with info will be stored If a null pointer is passed no information will be written stringLength Length of the character string buffer If the string is not long enough to accept all of the information only the first stringLength characters are returned info Enumerated type listed below specifying what information is required from the driver Returns The length of the string written to the character string buffer string by the function If one of the parameters is out of range or a null pointer is passed for string the function will return zero Values of info HRDL DRIVER VERSION 0 he version of PicoHRDL d11 1 0 0 onnected attached attached unit HRDL CAL DATE 5 alibration date of the unit 09Sep05 HRDL KERNEL DRIVER VERSION ernel driver version RDL ERROR 7 nos Error codes below Setting Error Codes below Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 25 Programmer s reference Error codes when info ERDL ER
33. nnel 1 and the MSB channel 16 no0fValues The number of samples to collect for each active channel Returns A non zero number if successful indicating the number of values returned O if the call failed or no values available Ordering of returned data example When two analog channels e g 1 and 5 are enabled and a digital channel is set as an input the data are returned in the following order Sample No 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 n 3 n 2 n 1 Channel pri 5 D 5 DID 5 DIL 5 DIAS DI 1 5 where n represents the value returned by the function and DI the digital inputs The channels are always ordered from channel 1 up to the maximum channel number ADC 24 channel 16 ADC 20 channel 8 If one or more digital channels are set as inputs then the first sample contains the digital channels Digital inputs The digital channels are represented by a binary bit pattern with O representing off and 1 representing on Digital input 1 is in bit 0 adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 24 5 4 8 HRDLGetUnitInfo short HRDLGetUnitInfo short handle char string short stringLength short info This function writes information about the data logger to a character string If the logger fails to open only info HRDL ERROR 7 is available to explain why the last open unit call failed When retrieving the driver version the handle value is ignored Argu
34. nstall Software link You may choose to install the driver when you install the PicoLog software by ticking the box labelled 32 Bit Drivers during the installation procedure Alternatively you can download the driver from our website at www picotech com Connecting the data logger You must install the software before plugging in the data logger When you have installed the software connect the data logger s USB cable to a spare USB port on your computer The following instructions describe the installation procedure for Windows XP SP2 The procedure for Windows Vista is simpler once the software is correctly installed just plug in the data logger and wait until Vista displays the message Device is ready to use When you first plug in the device your computer should show this message i Found New Hardware x Pico High Resolution Data Logger and then display the New Hardware Found Wizard Found New Hardware Wizard Welcome to the Found New Hardware Wizard This wizard helps you install software for Pico High Resolution Data Logger If your hardware came with an installation CD IP or floppy disk insert it now What do you want the wizard to do Install the software automatically Recommended Install from a list or specific location Advanced Click Next to continue lt Back Cancel adc20 en Copyright 2005 2010 Pico Technology Ltd All ri
35. p amp Repeat Loop until ready HRDLReady amp Collect data whenever you want with HRDLGetValues S S Appicatos USB RUN STREAMING _ ar Data E Status Device vi Data not I collected 1 Data ne 27 collected t Status adc20 en Copyright 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 42 5 6 2 5 6 2 1 5 6 2 2 Single value recording methods Collecting a single reading blocking This method collects a single reading and blocks the calling thread amp Open the data logger with one of the HRDLOpenUnit calls amp Set mains noise rejection with HRDLSetMains amp Get a single reading one channel only at a time with HRDLGetSingleValue 7 Application HRDLSetMains A Status HRDLGetSingleValue Collecting a single reading non blocking USB_READ_CHANNEL Device This method collects a single reading without blocking the calling thread amp Open the data logger with one of the HRDLOpenUnit calls amp Set mains noise rejection with HRDLSetMains amp Start the conversion for a single reading with HRDLCollectSingleValueAsync amp Wait until the reading is ready HRDLReady amp Get the reading from the driver with HRDLGetSingleValueAsync f Application HRDLReady 1 1 1 1 1 N ot HRDLGetSingleValueAsync Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 43 Glossary G
36. r vapor in the air to the maximum amount of water vapour that the air could hold at the current temperature USB Universal Serial Bus USB is a standard port that enables you to connect external devices to PCs A typical USB 1 1 port supports a data transfer rate of 12 megabits per second making it much faster than an RS 232 COM port Copyright O 2005 2010 Pico Technology Ltd All rights reserved adc20 en 45 Index Index A Access 3 ADC 20 1 10 ADC 24 1 10 Agilent VEE 39 Analog connector 12 B Block recording 40 C C 38 C 38 Calibration 10 CE notice 3 Channels 12 Common mode rejection ratio 10 Common mode voltage 10 Company address 4 Connection 5 Contact details 4 Conversion time 10 12 Copyright 3 D Data flow 40 Declaration of Conformity 3 Delphi 38 Digital I O 10 12 Dimensions 10 DLL 14 Driver 14 installing 5 E Earthing 2 Email address 4 EMC EMI 3 Emissions 3 Environmental conditions 10 F Fax number 4 FCC notice 3 Fitness for purpose 3 Functions 15 G Gain error 10 Grounding 2 H HRDLCloseUnit 16 HRDLCollectSingleValueAsync 17 HRDLGetMinMaxAdcCounts 18 HRDLGetNumberOfEnabledChannels 19 HRDLGetSingleValue 20 HRDLGetSingleValueAsync 21 HRDLGetTimesAndValues 23 HRDLGetUnitI nfo 24 HRDLGetValues 26 HRDLOpenUnit 27 HRDLOpenUnitAsync 28 HRDLOpenUnitProgress 29 HRDLReady 30 HRDLRun 31 HRDLSetAnaloginChannel 32 HRDLSetDigitallOChannel 33 HRDLSetinterval
37. re was continuously monitored for viruses during production but you are responsible for virus checking the software once it is installed CE notice The ADC 20 and ADC 24 meet the intent of EMC directive 89 336 EEC and meets the EN61326 1 1997 Class B Emissions and Immunity standard The ADC 20 and ADC 24 also meet the intent of the Low Voltage Directive and meet the BS EN 61010 1 2001 IEC 61010 1 2001 safety requirements for electrical equipment control and laboratory use standard A Declaration of Conformity is available from Pico Technology Ltd FCC notice This equipment has been tested and found to comply with the limits for a Class A digital device pursuant to Part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instruction manual may cause harmful interference to radio communications Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his or her own expense For safety and maintenance information see the safety warning A Declaration of Conformity is available from Pico Technology Ltd adc20 en Copyright 2005 2010 Pico Technology Ltd All rights reserved ADC 20
38. s 60 ms y Corcel Hel Voltage Range 1 250 my y Her Options I Differential input enable Copyright 2005 2010 Pico Technology Ltd All rights reserved adc20 en Getting started 10 Back at the ADC 20 or ADC 24 Channels dialog click OK 11 The PLW Recorder view should now display the voltage on channel 1 near O mV if nothing connected Vi rus recorder File Settings View Help dE Awaiting data filename Use File New data Channel 1 0 124 mY 12 Connect a suitable voltage for example from a 1 5 V battery to the channel Pin connections are marked on the logger and also listed in the Analog connector topic adc20 en Copyright 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 10 4 4 1 4 2 About the unit Introduction The ADC 20 and ADC 24 High Resolution Data Loggers offer the ultimate in precise and accurate readings Features such as true differential inputs galvanic isolation and software selectable sample rates all contribute to a superior noise free resolution The ADC 20 is equipped with a 20 bit A D converter and can maintain a gain error of 0 2 The four true differential inputs may be configured as eight single ended inputs or any combination in between such as two differential and four single ended The ADC 24 is equipped with a 24 bit A D converter and can maintain a gain error of 0 1 The eight true differential
39. s licensed not sold Pico Technology Limited grants a licence to the person who installs this software subject to the conditions listed below Access The licensee agrees to allow access to this software only to persons who have been informed of these conditions and agree to abide by them Usage The software in this release is for use only with Pico products or with data collected using Pico products Copyright Pico Technology Limited claims the copyright of and retains the rights to all material software documents etc contained in this release You may copy and distribute the entire release in its original state but must not copy individual items within the release other than for backup purposes Liability Pico Technology and its agents shall not be liable for any loss damage or injury howsoever caused related to the use of Pico Technology equipment or software unless excluded by statute Fitness for purpose As no two applications are the same Pico Technology cannot guarantee that its equipment or software is suitable for a given application It is your responsibility therefore to ensure that the product is suitable for your application Mission critical applications This software is intended for use on a computer that may be running other software products For this reason one of the conditions of the licence is that it excludes usage in mission critical applications such as life support systems Viruses This softwa
40. s reference 5 4 2 HRDLCollectSingleValueAsync short HRDLCollectSingleValueAsync short handle short channel short range short conversionTime short singleEnded This function starts the unit sampling one value without blocking the calling application s flow Used in conjunction with HRDLGetSingleValueAsync and HRDLReady Arguments handle Handle returned by HRDLOpenUnit channel Channel number to convert If the channel is not valid then the function will fail range The voltage range to be used If the range is not valid the function HRDLGetSingleValueAsync will return O conversionTime The time interval in which the sample should be converted If the conversion time is invalid the function HRDLGetSingleValueAsyn will fail and return 0 singleEnded The type of voltage to be measured O differential nonzero single ended Returns 1 if a valid handle is passed and the settings are correct 0 if not adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 18 5 4 3 HRDLGetMinMaxAdcCounts short HRDLGetMinMaxAdcCounts short handle long minAdc long maxAdc short channel This function returns the maximum and minimum ADC count available for the device referenced by handle Arguments handle Handle returned by HRDLOpenUnit minAdc Pointer to a long used to return the minimum ADC count available for the unit referred to by handle maxAdc Pointer to a long
41. the unit unless you exceed the overvoltage protection voltage range adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 44 LSB Least significant bit In a binary word the least significant bit has the value 1 MSB Most significant bit In an n bit binary word the most significant bit has the value 27 n 1 Noise free resolution Any measurement is subject to noise In a digital measuring instrument a result with a resolution of n bits may include m bits of noise The noise free resolution is then n m bits Noise rejection The ability of the data logger to attenuate noise in a given frequency range The ADC 20 ADC 24 can be programmed to reject noise at either 50 hertz or 60 hertz The noise rejection ratio is defined as NRR dB 20 log10 Vin Vmeas where NRR dB is the noise rejection ratio in decibels Vin is the noise voltage at the input and Vmeas is the noise voltage that appears in the measurement Overload protection Overload protection is characterised by the maximum voltage that can be applied across the inputs of the data logger without causing damage to it The ADC 20 and ADC 24 are protected to 30 V Resolution A value in bits indicating the number of unique digital values that the converter can produce If the resolution is n bits then the number of unique values is 2 to the power n RH Relative Humidity RH is the ratio of the amount of wate
42. utput then the pin can be set high on or low off While the device is sampling the direction cannot be changed but the value of an output can Arguments handle Handle returned by HRDLOpenUnit directionOut The directions of the digital IO pins either input or output The four least significant bits must be a combination of HRDL DIGITAL IO CHANNEL constants see below digitalOutPinState f the pin is set as an output it can be set high or low by a combination of HRDL DIGITAL IO CHANNEL constants see below enabledDigitalIn Sets the digital input as active Use a combination of HRDL DIGITAL IO CHANNEL constants see below Returns O if failed 1 if successful If the function fails call HRDLGetUnitlnfo with info HRDL SETTINGS ERROR 8 to obtain the specific setting error Pin values for directionOut digitalOutPinState and enabledDigitalIn direction0ut enabledDigitalIn Description TAL ITO CHANNEL _ IO Pin 1 L IO CHANNEL IO Pin 2 L IO CHANNEL TAL IO CHANNE adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 34 Examples amp To set digital channels 1 and 2 to input and digital channels 3 and 4 to output directionOut HRDL DIGITAL IO CHANNEL 4 8 HRDL DIGITAL IO CHANNEL 3 4 12 amp To set digital channel 4 high and digital channel 3 low digitalOutPinState HRDL DIG
43. valid handle is passed and the function succeeds 0 if not Sample code Code extract to get a single value reading without blocking the calling thread void main BOOL bConversionFinished FALSE short channelNo long value short handle open and initialise the unit set the channel parameters channelNo HRDL ANALOG IN CHANNEL 1 range HRDL 2500 MV singleEnded TRUE bConversionFinished FALSI J El while true PollSingleValue handle amp bConversionFinished amp value channelNo range singleEnded EJ if bConversionFinished TRU do something with the value channelNo adc20 en Copyright O 2005 2010 Pico Technology Ltd All rights reserved ADC 20 ADC 24 User s Guide 22 this would be HRDL_ANALOG_IN_CHANNEL_8 for the ADC 20 if channelNo gt HRDL ANALOG IN CHANNEL 16 channelNo HRDL ANALOG IN CHANNEL 1 else do something else while waiting for the reading from the 17 unit void PollSingleValue short handle BOOL bConversionFinished long lValue short channel short range short singleEnded static BOOL bStartConversion FALSE short overflow test to see if the conversion has finished if bStartedConversion if HRDLReady handle HRDLGetSingleValueAsync handle lValue amp overflow bConversionFinished TRUE a Ly E E bConversionStarte
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