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CALIBRATION
TEC Calibration Procedures
06_03 TCM-39032 11
CHAPTER 3
5 Press and hold the (PARAMETER) SET switch and turn the ADJUST knob until the TEC
display indicated the same resistance recorded for the metal film resistor.
6 Release the (PARAMETER) SET switch to store the new value into non-volatile memory
on the TCM-39032. After the (PARAMETER) SET switch is released, the LDC-3900 will
beep and return to its former state (before calibration).
7 Switch the THERM RANGE switch (back panel) to the 10µA position and repeat this
procedure with the other resistor.
Remote Operation Thermistor Calibration
The following procedure is for calibrating the 100 µA and 10 µA constant current
sources so that the thermistor resistances for these ranges will be as accurate as
possible. This procedure is for remote (GPIB) operation.
1 Set the SENSOR SELECT switch (bank panel) to the THERM position and set the
THERM RANGE switch to the 100 µA position.
2 Measure and record the exact resistance of the metal film resistors. (A 4-point probe
resistance measurement is recommended.)
3 Connect the correct metal film resistor to the TCM-39032 thermistor input (pins 7 and 8).
Use nominal values of 10 KΩ for the 100 µA setting and 100 KΩ for the 10 µA setting.
4 Enter the “TEC:CHAN x” command over the GPIB to select the channel of the TCM-
39032 to be calibrated, where x = the channel number.
Enter the “TEC:CAL:SENsor” command. The TEC display will show the resistance value.
The LDC-3900 will beep when it is ready to accept a new calibration value.
If this value is to be measured and entered remotely via a GPIB controlled DMM, for
example, the measured value of the resistance should not be entered until the LDC-3900
is ready to receive it.
The LDC-3900 will be ready to receive the resistance value when, after a
“TEC:CAL:SENsor?” query is sent, the response from the LDC-3900 is “1”.
5 Input the actual resistance (in kΩ) measured by the external DMM (as an <nrf value>) via
the “TEC:R <nrf value>” command.
After the “TEC:R” value is entered, the “*OPC?” query may be used to determine when
the calibration sequence is done. However, the “*OPC”, or “*WAI” command or “*OPC?”
query should not be issued until after the expected “TEC:R” value is entered or the
system will “hang”. This happens because the LDC-3900 will wait indefinitely for an input,
yet not allow any input until the calibration is finished.
6 Once the “TEC:R” value is sent, the LDC-3900 will beep and return to its former state
(before calibration). The “OPC?” query may be used (after the “TEC:R” value is sent) to
determine when the calibration is completed.
The operation complete flag (bit 0 of the Standard Event Status Register) may be used to
trigger a service request. This type of interrupt is enabled by setting bit 0 of the Service
Request Enable Register (via the *ESE command) and bit 5 of the Service Request
Enable Register (via the *SRE command). Service request (SRQ) handling depends on