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4.5 Coefficients

The thermometer uses Callendar– Van Dusen coefficients to calculate exact temperature 

of the probe. Each probe has unique set of coefficients developed while calibration. To 

achive proper readings, these unique coefficients should be stored in the thermometer’s 

memory. In order to do so, follow Chapter 5 instructions. If no coefficients are typed, the 

thermometer uses default values presented in Tab2.

If the resistance value is set to be displayed, the resistance reading is always a raw data – 

data without any mathematical computing.

4.6 PC interface

The meter supports USB 2.0 and RS-232 interfaces. The protocol is compatible with SCPI 

language. The examples of the most common commands are listed below.

All details connected with SCPI communication are described in appendix B.

A suitable Microsoft Windows USB driver file: „STM_VCP_DRIVER.zip” can also be down

-

loaded from the web site listed above.

The most frequently used commands are listed below (this symbol // marks the comment):

*idn?$00   

 

 

 

//identify command, response will be eg.

 

 

 

 

 

„Leyro Instruments, LDT 2000 OPT02,  

 

 

 

 

 

0413,1.1”

:syst:date?; time?$00  

 

 

//date and hour question

:syst:date 2013,04,04; time 23,22,00$00  

//date and hour setting

:disp:menu:name res$00  

 

 

//enabling resistance display

:disp:menu:name grad$00    

 

//enabling gradient display

:init:cont off; cont?$00  

 

 

//enabling sequential results sending

:meas:temp:val? (@1)$00  

 

 

//send temperature measured in CH1

:sens:aver:coun 4$00  

 

 

//enable averaging of 4 samples

:cal:sec:stat 1,2804$00;:cal:sec:stat?$00  

//enabling calibration, response: „ON”

:cal:res:val 100.0034$00  

 

 

//internal resistor calibration using

 

 

 

 

 

standard resistor connected to CH1  

 

 

 

 

 

(value 100.0034 Ω)

Содержание LDT 2000

Страница 1: ...1 LDT 2000 PRECISION THERMOMETER MANUAL...

Страница 2: ...f the described products The document may contain technical inaccuracies and typographical errors The content will be revised on a regular basis These changes will be implemented in later versions The...

Страница 3: ...6 Internal battery 3 7 Calibration period 3 8 Calibration period 4 Advanced user information 4 1 Block diagram 4 2 Probes 4 3 Extender 4 4 Resistance calibration 4 5 Coefficients 4 6 PC interface 5 T...

Страница 4: ...Default commands 7 3 Status registers 7 3 1 STB status register 7 3 2 Events register ESR 7 3 3 Operation register OPER 7 3 4 Reliability register QUES 7 3 5 Errors queue 7 3 6 Mask registers 7 4 Com...

Страница 5: ...CALibration calibration commands 7 6 6 1 ALL autocalibration 7 6 6 2 SECure calibration unlocking 7 6 6 3 RESistance resistance measurement calibration 7 6 6 4 CHannel 1 and CHannel 2 probes calibrati...

Страница 6: ...ieve optimum functioning of the equip ment 1 2 General safety Instructions The LDT 2000 temperature meter is a device designed for laboratory indoor use It is powered from 85 to 250V line therefore th...

Страница 7: ...eans of Current Reversal technique The autocalibration sequence is a background task performed continuously The LDT 2000 has been designed to make operating as simple as possible An advanced configura...

Страница 8: ...102 6 mm ca 1 5 kg 3 OPERATION 3 1 Safety The LDT 2000 temperature meter is a device designed for laboratory indoor use It is powered from 85 to 250V line therefore the user should work with respect t...

Страница 9: ...ts about 40s to 120s depending on used averaging N 1 to 10 The screens are presented in order of apperance The first screen fig 1 shows general information about the instrument Name of the manufacture...

Страница 10: ...vailable for Microsoft Windows Operating Systems The software supports 1 Monitoring measured parameters in time domain using adjustable scale display 2 Data acqiusiton and recording Advanced controlls...

Страница 11: ...ry 12 months if the working temperature is T 200 C 4 Advanced user information 4 1 Block diagram The LDT 2000 thermometer is a microprocessor based meter which accurately measu res probe s resistance...

Страница 12: ...is preferred Using long extender in industrial environment with very high electromag netic interferences level can increase the measurement noise 4 4 Resistance calibration In case of performing resi...

Страница 13: ...d below All details connected with SCPI communication are described in appendix B A suitable Microsoft Windows USB driver file STM_VCP_DRIVER zip can also be down loaded from the web site listed above...

Страница 14: ...14 5 Typical performance of the thermometer...

Страница 15: ...15...

Страница 16: ...16...

Страница 17: ...17...

Страница 18: ...nd requirements To start the installation run setup exe file and confirm to deploy the program After quick setup utility runs for the first time Later it will be available from desktop shortcut fig 13...

Страница 19: ...can be chosen by expanding combo list next to CONNECT button and selecting device s serial number After pressing the mentioned button communication with thermometer will initialize and other functions...

Страница 20: ...since the start of collection it grows to the right The chart can store up to 24 hours of samples and after that time the chart stops receiving further data The chart however can be reset any time by...

Страница 21: ...ive keyboard up down keys or with mouse wheel if exists The chart can be copied to clipboard as a bitmap and used e g as a report in a document This can be done by pressing Copy to clipboard button lo...

Страница 22: ...this field 3 Mark End field 4 As in p 2 input date time this time adequate to 3th of September half past 10 PM 5 Set Interval s field to 1800 30 times 60 seconds 6 Press START button After completing...

Страница 23: ...the resistance of the probe s sensor NONE additional results are not displayed for clearance Average count sets from 1 to 10 the amount of samples that would be averaged to cal culate current level A...

Страница 24: ...cates last calibration date for probe This field is filled automaticcaly during calibration R0 probe s resistance at 0 C Coeffs A B C coefficients for Callendar Van Dusen equation for calculating resi...

Страница 25: ...the buttons attached to each row of the table It is reccomended to export certain probe s data to a file for troubleshooting The Calibration tab allows to modify probe s memory content and to calibrat...

Страница 26: ...l word Therefore MEAS MEASURE but also MEASUR or MEASURE1 will execute the same command Using mnemonics is recommended since not all full names are properly recog nized Character case in command is ig...

Страница 27: ...means the device should send back the temperature value If no response comes back it means an error had ocurred 7 2 6 Parameters Both plain commands as well as queries can accept parameters These can...

Страница 28: ...ogues by default therefore to enter any ca talogue its name must appear in message Per example then to read temperature s value gradient and resistance it can be commonly achieved by sending MEAS TEMP...

Страница 29: ...er failure always 0 7 3 3 Operation register OPER Sixteen bit register of currently executed operations Specific bit is set while an operation continues and is zeroed after it passes Only three bits a...

Страница 30: ...f any characters except the special ones Maximum length is 15 characters 7 4 5 Channels list Used for setting the amount and numbers of measured channels It implements somewhat specific format It is w...

Страница 31: ...int sets the mask of status register STB to decimal value passed as parame ter SRE reads the value of status register mask STB STB reads the value of status register STB afterwards the register is re...

Страница 32: ...IN TMAX CALibration ALL ALL SECure STATe boolean password RESistance VALue R value VALue R value DATE CH1 CHannel1 R0 R0 value COEFficient A B C PCORrection a0 a1 a2 NCORrection a0 a1 a2 TMIN Tmin val...

Страница 33: ...alues To initiate sending certain query must be sent also to precise what should be sent FETC READ and MEAS commands Results are sent with second interval 7 6 2 2 CONFigure Command used for configurat...

Страница 34: ...urement and then sends back the result READ can be treated as a sequence of following commands 1 INIT 2 FETC Both commands need proper configuration of measurement first It can be set using CONFigure...

Страница 35: ...a query for this command will result in sending name of a presently used scale After switching off the thermometer stores scale that had been used recently 7 6 4 INPut measurement circuit configuratio...

Страница 36: ...efault command checking exceeding of limit can be done in one of two ways 1 SENS OVER CH1 TMIN 2 OVER CH1 TMIN Over range condition is set if within the following 20 measurements of temperature over 1...

Страница 37: ...tor Sending the same command as a query CAL RES VAL R value will prompt the device to return calibration s state zero is successful or error number in case of failure Because the calibration itself la...

Страница 38: ...ing memory in a first channel of the probe can be done in two ways 1 MEM CLEar NAME CH1 2 CLEar NAME CH1 To prevent accidental deletion of data before attempting to erase the memory the user must firs...

Страница 39: ...ode from queue After the readout the error is removed from queue Full list of notified errors is described in separate chapter 7 6 10 2 DATE year month day Setting and reading of current date from the...

Страница 40: ...METER MEMORY ERROR no communication with analogue board memory 150 CALCULATION ERROR error occurring when using certain coefficients the algori thm is divergent or gives forbidden results 151 CALCULA...

Страница 41: ..._____________________ _____________________________________________________________________________ _____________________________________________________________________________ ______________________...

Страница 42: ...CENTRAL OFFICE LEYRO INSTRUMENTS SL Avda Somosierra 24 28703 San Sebasti n de los Reyes Madrid Tel 34 912 835 502 info leyro net www leyroinstruments com...

Страница 43: ......

Страница 44: ......

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