Keithley 2010, Руководство по обслуживанию

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Verifying temperature
Thermocouple and RTD temperature readings are derived from DC volts and ohms readings
respectively. For this reason, it is not necessary to independently verify the accuracy of
temperature measurements. As long as the DC volts and ohms functions meet or exceed their
respective specifications, temperature function accuracy is automatically verified. However,
temperature verification procedures are provided below for those who wish to separately verify
temperature accuracy.
Thermocouple temperature
1. Connect the DC voltage calibrator output terminals to the Model 2010 INPUT jacks
using low-thermal shielded connections. (Use 2-wire connections similar to those shown
in
Figure 1-1 .)
2. Configure the Model 2010 for °C units, type J temperature sensor, and 0°C simulated
reference junction as follows:
A.
Press SHIFT then SENSOR, and note the unit displays the temperature units:
UNITS: C. (If necessary, use the cursor and range keys to select °C units.)
B. Press ENTER, and note the unit displays the sensor type: SENS: TCOUPLE. (Use
the cursor and range keys to select a thermocouple type temperature sensor.)
C. Press ENTER. The unit then displays the thermocouple type: TYPE: J.
D. Select a type J temperature sensor, and then press ENTER. The unit displays the
reference junction type: JUNC: SIM.
E. Make sure the simulated reference junction type is selected, and then press ENTER.
The unit displays the current simulated reference junction temperature: SIM: 023.
F. Using the cursor and range keys, set the reference junction temperature to 0°C, and
then press ENTER to complete the temperature configuration process.
3. Select the temperature function by pressing the TEMP key.
4. Source each of the voltages summarized in Table 1-7 , and verify that the temperature
readings are within limits. Be sure to select the appropriate thermocouple type for each
group of readings. (See step 2.)
Table 1-7
Thermocouple temperature verification reading limits
Thermocouple
type
Applied DC
voltage*
Reading limits
(1 year, 18°C–28°C)
J
K
-7.659mV
0mV
42.281mV
-5.730mV
0mV
54.138mV
-190.60 to -189.40°C
-0.50 to +0.50°C
749.50 to 750.50°C
-190.60 to -189.40°C
-0.50 to +0.50°C
1349.20 to 1350.80°C
* Voltages shown are based on ITS-90 standard using 0°C reference junction
temperature. See text for procedure to set reference junction temperature.
1-12 Performance Verification