13
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)
Summary of Contents for LDT 2000
Page 1: ...1 LDT 2000 PRECISION THERMOMETER MANUAL...
Page 14: ...14 5 Typical performance of the thermometer...
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