User Manual
Contents
1. Differential input range 5 V PGA PGA gains 1 2 4 8 16 32 64 Input impedance 80 MQ Error gain 1 2 0 01 15 uV Evaluation possible Platinum RTDs and K type thermocouples 1 Higher input ranges in different combinations are available on request Current source outputs Number 4 Current 3 1mA Accuracy 2 0 25 Voltage range 40 3 8 V 2 Reference voltage tolerance should be added for absolute measurements 3 Other values in different combinations are available on request Digital inputs Number 4 Low level 0 0 8V High level 2 5V Input protection 4 8 5 V Input resistance 50 KQ typical Protocol supported 1 wire temperature sensors Supply and reference outputs 5V accuracy 2 5 linear regulation Maximal current 100 mA 3 3V accuracy 3 switch mode regulation Maximal current 500 mA Ref voltage accuracy 0 05 0 01 on request Temp coefficient 10 ppm C Maximal current 9 mA Data storage Medium Secure Digital SD card up to 2 GB File system FAT12 FAT16 or FAT32 Data format Comma Separated Value CSV with user defined formatting Interfaces USB Standard USB 1 1 Class Mass Storage Class access to SD card RS 232 optional Connector DB9 DTE male Lines TxD RxD RTS CTS DSR DTR RS 4852. 000095 Log started at 16 18 00 2009 08 18 Log stopped at 16 18 57 2009 08 18 16 18 45 3 763444 1 23 0 45 45 47 46 5 16218250 3 763445 25237 0 453 45 473 463 5 16 18 55 3 763442 1 23 0 45 45 47 46 5 Interpretation First sample was taken at 2009 08 18 16 18 00 Logging process was manually stopped at 2009 08 18 16 18 57 If logging is stopped because of full card or empty battery this info Card or Bat is written at the end of Log stopped line If this line is absent filled with spaces it is indication that logging ended in an uncontrolled manner e g the card was removed or system power was lost Voltage of 3 76344 V is present between AO and ground Voltage of 1 23 V is present between A1 and ground Voltage of 0 45 V is present between A3 and A2 Platinum sensor has temperature of 45 C math is for PT100 and excitation current of 1 mA or PT1000 and excitation current of 0 1 mA Two wire sensors with addresses 28C358110100006F and 28954B0202000095 were detected on D3 and have temperatures of 47 C and 46 C Pins D2 and D0 are at logical one while D1 is at logical zero Real time clock setup Internal RTC of the datalogger can be set by writing the desired date and time to a file named set_clk txt The file is parsed when START STOP key is pressed and clock set if deletion of the file is successful In that case logging will not star
3. Operation multi drop device Speed 250 kb s Power supply External voltage 10 60V Power external supply 5 W maximal battery charging 0 3 W typical 0 05 W in sleep mode Battery optional Pb 3 cell 6 V 1 2 Ah 4 or Li ion 2 cell 7 4 V 2 2 Ah connector for external battery RTC battery Lithium cell CR2032 USB supply 100 mA typical for SD card access only Options different voltage range MPP tracking for PV module power supply USB battery charging 4 Requires higher enclosure Dimensions Width x Depth 190 x 140 mm Height 30 50 70 mm Weight 320 g without battery 420 g with Li ion battery 650 g with Pb battery Designed by University of Ljubljana Faculty of Electrical Engineering Tr a ka cesta 25 1000 Ljubljana Slovenia Laboratory of Photovoltaics and Optoelectronics http Ipvo fe uni lj si http pvo fe uni lj si datalog Dr Marko Topi Head of LPVO E mail marko topic at fe uni lj si Phone 386 1 4768 470 Dr Bo tjan Gla ar The designer E mail bostjan glazar at fe uni lj si Phone 386 1 4768 723 Last update April 2010
4. University of Ljubljana Faculty of Electrical Engineering Laboratory of Photovoltaics and Optoelectronics Datalogger DL844 User s manual Draft April 2010 Introduction The datalogger can read up to 8 analog voltages and 4 digital channels and store data to an SD card or output it to RS 485 port 4 current sources are provided to bias sensors connected to the datalogger Data can be time stamped with internal battery backed clock The FAT formatted card can also be read from RS 485 RS 232 or USB port Configuration can be stored on the card or transferred through RS 485 Various supply options are available including internal rechargeable battery Specifications in this manual are preliminary and are subject to change without prior notice Local user interface Buttons RST Holding this button at power on will reset RS 485 address to 53 decimal and clock to 2000 01 01 0 00 00 The button can be also used to clear a run time error i e turn off error LED START Pressing the button will start or stop logging process PWR Pressing the button will power on off the datalogger LEDs PWR green Signals that the datalogger is powered Blinks when it is running on batteries and is solid when on external power BAT yellow Blinks when the main battery is low USB red Lights when the datalogger is connected to USB an enumerated Logging process cannot be started when this LED is lit SAMP green Lights when sample is being tak
5. d by 3 pole modular plug connectors The pinouts of all connectors are visible from the image above G and GND stands for ground connection Ground is common to all connections however analog and digital ground should not be mixed 5V REF GND Power supply output 5 V is filtered supply and present only when bias is present REF is reference voltage output and is not intended for supply of power hungry external circuits GND is analog ground ANALOG INPUTS Inputs for analog signals Input range depends upon configuration Differential signals should be defined not floating G is analog ground EXCITATION These pins output constant current if voltage on them is within certain limits G is analog ground DIGITAL I O These pins go to CMOS 3 3 V logic through protection circuits G is digital ground 5V 3V3 GND Power supply output 5 V is present only when bias is present 3V3 is always present even when the datalogger is turned off 5V output can be used as an enable signal to draw higher current from 3V3 pin G is digital ground RS 232 RS 232 interface has DTE pinout and can be used to monitor output data Data will be output in the same format as to the file Back panel DC in BAT bite RST START PUR err O use k n G Secure a O LOG O BAT fal samMP O PWR DC in These are connectors for external supply voltage Both of the connectors are in parallel Ground is the same as for other con
6. en LOG yellow Lights when logging is active or when data is transferred over USB ERR red Signals error with one long blink and certain number of short blinks see table below Blinking is continued while logging is active In that case blinking can be stopped by pressing the RST key At power on logging is not active Logging can only be started when an SD card is inserted and USB cable is not connected When logging is started configuration file on the card will be parsed and logging will begin Logging is normally stopped with key or remote command but will also be stopped when USB cable is plugged in and USB enumerated memory card is filled up and battery is empty Logging is also stopped when the power button is pressed The datalogger will be automatically turned of when battery is empty Note that when the datalogger is connected to USB it is still powered from battery unless external power is applied Blinks Error 1 No memory card was detected 2 The card is full 3 Other card error 4 The card is write protected 5 No configuration file was found 6 Error parsing configuration file 7 1 wire error No sensor was found on one of specified channels or a sensor can not be read Connections Front panel RS 232 DTE ANALOG INPUTS EXCITATION DIGITAL 1 0 2 3 601 6 23 6 45 6 67 6 01 6 ole o1lo2a aa8 DataLog LPUO UL FE Connection of measurement signals to the datalogger is accomplishe
7. ile until lt size gt bytes are transferred There should be pause of at least 10 ms between packets to allow data to be processed MMEM DEL lt file_name gt Deletes a file from the mass storage device SYST ERR SYST ERR NEXT Both commands retrieve an error from a first in first out FIFO queue If more than 19 errors have occurred the last error stored in the queue is replaced with 350 Too many errors If no errors have occurred the datalogger responds with 0 No errors Error queue is cleared on power on and after CLS command Error codes 0 Noerror Error queue is empty 100 Command error Command was not recognized by the datalogger 109 Missing parameter Fewer parameters were received than required for the header 113 Undefined header A command was received that is not valid for the datalogger Check spelling 150 String data error A string parameter filename in MMEM DATA command was not correctly received Check that the filename is surrounded with double quotes 221 Settings conflict Command cannot be currently executed Sampling cannot be triggered MEAS or INIT command and configuration cannot be changed when logging process is active Use READ command to retrieve the last sample Memory card cannot be accessed when USB connection is active 250 Mass storage error There is a problem accessing memory card Check that the required file exists and that the card is properly formatted and inser
8. nections including front panel connections BAT This connector is intended for external battery and is connected in parallel to internal battery It is output of power supply that receives power from DC in connectors All the circuitry is powered from this supply RS485 Connection for RS 485 bus Using internal jumpers termination and pull up resistors can be enabled Datalogger is a slave in master slave configuration USB USB B type receptacle for connection to a USB host The datalogger acts as a Standard Mass Storage Device to access the Secure Digital card LAN 8P8C socket for connection to 1OOBASE TX or 1OBASE T network Secure Digital Socket for a Secure Digital memory card The card should be inserted face up that is with pins facing down Configuration file syntax Configuration file must be named config txt and is loaded and interpreted at beginning of logging operation Data will be output to a new file named log NNNN txt The 4 digit number will be one more than the highest already existing number If the highest existing number is 9999 search for free number will begin with 0001 If none is found data will be appended to file named output txt Each sample is in new line whereas channels are separated with semicolon Buffered data is flushed to the card every 10 minutes to prevent loss of data General configuration Each parameter is given in a separate line PER lt value gt min hr Sample period Default val
9. t Date and time must be in the format YY YY MM DD HH MM SS Additional internal battery is provided for independent power of RTC RS 485 commands Only one command is allowed in a packet Maximum length of user data in a packet is currently 248 bytes If the command is not a query nothing is returned IDN Return product identification string The string include last compile date CLS Clears error queue ADR lt address gt ADR Sets or reads RS 485 device address Address set will be stored to FLASH memory and taken into account on next system start up LOG RUN ON OFF LOG RUN Start or stop logging process or query state Configuration is always taken from config txt file and results are output to output file CHAN lt confs gt CHAN Set or read channel configuration for RS 485 query only The configuration is lost after starting logging process Syntax is the same as for config txt file character can be used instead of new lines After logging is stopped its configuration will be used for RS 485 queries INIT Start measuring with current configuration Nothing is returned This command can only be used when logging is not active MEAS Start measuring with current configuration and return result The format is the same as in output txt file but only one sample is measured and returned This command can only be used when logging is not active READ Read last sample taken This command can be used
10. ted 285 Program syntax error There is a syntax error in configuration given with CHAN command 350 Queue overflow The queue is full because more than 19 errors occurred RS 485 protocol Protocol on top of RS 485 interface is a multi drop master slave protocol Data is transferred in addressed packets Address of master must be 0 The datalogger will respond to requests and cannot be programmed to continuously send data Large data blocks MMEM catalog and files will span multiple packets Data rate is 250 kb s with standard serial formatting i e 8N1 The bus can be internally terminated with 120 Q by installing jumper JP107 Jumpers JP105 and JP106 enable pull up pull down resistors to guarantee idle state These resistors are disabled when datalogger is turned off to save power If more than datalogger is used in a system unique address much be set to each of them Byte Meaning Description 0 STX Start delimiter 0x55 1 destination Destination address 2 source Source address 3 length Length of payload n 4 n 4 data Payload max 248 bytes n 5 CRC MSB CRC 16 IBM checksum n 6 CRC LSB polynomial 0x8005 n 7 ETX End delimiter OxAA Specifications Analog inputs Number 8 single ended 4 differential any combination possible Max scanning rate 1 S s Resolution 24 bits Absolute input range 1 0 3V Input protection 10 10 V
11. ue is 1 minute Default unit is second Channel configuration Each channel configuration is given in a separate line Order of parameters is not important however FRMT must be the last one lt function gt lt channel gt GAIN lt gain gt BUFF ON OFF MATH lt k gt lt n gt FRMT lt format string gt functions VOLT Measure voltage Default for analog channels BIT Bit s value Default for digital channels PTx Convert value for Platinum RTDs Input value of 1 V represents 0 C Algorithm 3 4 order polynomial is applied after math TCK Convert value for K type thermocouple Input values are in volts Algorithm 9 8 order polynomial is applied after math TEMP Measure temperature of 1 wire sensors on a digital channel TIME Time in the format hh mm ss DATE Date in the ISO format YY YY MM DD CLCK Time and date Default for RTC channel VBAT Internal battery voltage Default for SYS channel VEXT External supply voltage IEXT External supply voltage channel Syntax lt type gt lt number gt type A analog D digital RTC real time clock SYS system variables number number from 0 to number of channels 1 omitted for RTC and SYS channel E g A0 A3 DO For differential measurements lt channel gt lt channel gt e g A1 A0 For byte value lt highest bit gt lt lowest bit gt e g D3 D0O GAIN Sets PGA gain Supported
12. values are 1 2 4 8 16 32 and 64 Default and recommended is 1 Gain is taken into account for value output i e no additional scaling is necessary BUFF Turn buffer for analog channels on or off Default and recommended is on MATH Applies 1 order polynomial to measured value i e scaling and offset addition It is applied before algorithm that gives physical value e g Platinum RTD FRMT Define output format string FRMT must be the last parameter and ends at the end of the line C language syntax is used Integer value is given for pure digital channels d 0 x or X type whereas float value is used for analog channels temperatures and system channel of e E g or G type Useful to reduce precision and to give units to results Default is d for integer values and of for analog values The parameter is completely ignored for RTC channel Maximum length is 15 characters Example Configuration file config txt PER 5 TIME RTC AO Al FRMT 2f A3 A2 FRMT 2f PTx A4 MATH 10 0 TEMP D3 D2 DO Sample every 5 seconds Make 7 measurements time 2 single ended voltages 1 differential voltage RTD temperature temperature of 1 wire sensors 3 bit value Output file output txt Starting datalogger 2 channels configuration PER 5 TIME RTC AO Al FRMT 2f A3 A2 FRMT 2f PTx A4 MATH 10 000000 0 000000 TEMP D3 D2 D0 l wire sensors on D3 28C358110100006F 28954B0202
13. whenever the sample is ready 1 e after taking the first sample during logging process or after performing measurement with INIT or MEAS commands MMEM Subsystem for access to files on SD card Only files in the root folder can be accessed Commands supported are CAT DATA DATA and DEL Commands can also be used during logging MMEM CAT The CATalog command is query only and returns information on the current contents and state of the mass storage media Sizes are in bytes The returned format is lt amount_of storage _used gt lt amount_of storage available gt lt file entry gt Each lt file entry gt is a string in the form lt file_name gt lt file_type gt lt file_size gt File type is always empty Large listings will span over multiple packets In that case all packets but last will end with comma denoting another packet MMEM DATA lt file_name gt lt data gt The command loads lt data gt into the file lt file_ name gt lt data gt is in 488 2 block format lt file_name gt is string data The query form is MMEMory DATA lt file_name gt with the response being the associated lt data gt in block format Block format lt n gt lt size gt lt binary_data gt lt size gt is number of useful bytes in the block in decimal format lt n gt is number of characters in lt size gt Large files will span over multiple packets When writing file subsequent packets will be assumed as part of the f
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