Keithley 2750 - Page 31

Model 2750 Multimeter/Switch System Service Manual Performance Verification 1-19
2750 Verification
RTD temperature
1. Connect the precision decade resistance box (listed in Table 1-1) to the Model
2750 INPUT and SENSE jacks using four-wire connections. (See Figure 1-5 for
similar connecting scheme.) Be sure the INPUTS switch is in the FRONT position.
2. Configure the Model 2750 temperature function for °C units and RTD temperature
sensor (=0.00385) as follows:
a. Press SHIFT then SENSOR, and note the unit displays the temperature units:
UNITS: C.
b. Press ENTER, and note the unit displays the sensor type: SENS: TCOUPLE.
c. Using the cursor and range keys, set the display as follows: SENS: 4W-RTD.
d. Press ENTER, and note the unit displays: TYPE: PT100.
e. Using the cursor and range keys, set the unit for the following display: TYPE:
PT385.
f. Press ENTER to complete the temperature configuration process.
3. Select the temperature function by pressing the TEMP key.
4. Set the decade resistance box to each of the values shown in Table 1-9, and verify
that the temperature readings are within the required limits.
Tab le 1- 8
Thermocouple temperature verification reading limits
Thermocouple Type Applied DC Voltage* Reading Limits (1 year, 18°C to 28°C)
J
K
-7.659mV
0mV
42.280mV
-5.730mV
0mV
54.138mV
-190.2 to -189.9°C
-0.2 to +0.2°C
749.8 to 750.2°C
-190.2 to -189.8°C
-0.2 to +0.2°C
1349.8 to 1350.2°C
*Voltages shown are based on ITS-90 standard using 0°C reference junction temperature. See text for proce-
dure to set reference junction temperature.
Tab le 1- 9
Four-wire RTD temperature verification reading limits
Applied Resistance* Reading Limits (1 year, 18°C to 28°C)
22.80
100.00
313.59
-190.06 to -189.94°C
-0.06 to +0.06°C
599.94 to 600.06°C
*Based on  = 0.00385. See text.