Agilent Technologies 34970A, Service Manual, Page: 114 / 273

Thermocouple Reference Junction (Optional)
Note:
You should perform these verification and adjustments if you
are using the modules for thermocouple measurements.
To make a thermocouple measurement a known reference junction
temperature measurement must be made. The reference junction
temperature is measured by two solid state temperature sensors in
the input connection area on the module. The adjustments store
calibration constants used to correct the measurements from the
temperature sensors.
Thermocouple measurements are only supported by the 34901A,
34902A and 34908A.
Thermocouple Reference Junction Verification
1
Read “Plug-in Module Test Considerations” on page 87.
2
Connect a calibrated thermocouple with an accuracy of 0.1
°
C or
better to one of the following channels:
For the 34901A: Channel 10
For the 34902A: Channel 8
For the 34908A: Channel 10
3
Install the module in slot 100.
4
Place the J Type calibrated thermocouple at a known temperature
(ice bath or calibrator).
5
Select Channel 110 (or 108). Configure the channel as follows:
TEMPERATURE
THERMOCOUPLE
J TYPE
INTEG 10 PLC ( Advanced menu)
INTERNAL REF ( Advanced menu)
Before executing each test, you must press to enable reading
monitoring on the selected channel (or use the
ROUTe:MON
command
from the remote interface).
6
Subtract the thermocouple error from the displayed temperature.
Verify the result is within
±
1.0
°
C of the known temperature (set in
step 4).
Chapter 4 Calibration Procedures
Thermocouple Reference Junction (Optional)
112