Fluke 52 - Manual (Page 19)

Thermometer
Calibration and Offset Adjustment
11
11. To ignore the calibration changes, use
K or N, and select “
CAL Abrt ” and press
E.
12. Proceed to Reference Junction Calibration.
Reference Junction Calibration
Note
This procedure is described using an ice bath and a K-type thermocouple.
It can be performed in
°
C,
°
F, or K with any thermocouple and a known,
accurate temperature between 0
°
C (+32
°
F) and +50
°
C (+122
°
F).
Note
It is important that the temperature of the thermocouple and the internal
temperature of the thermometer (the reference junction) have stabilized.
To calibrate the reference junction, follow these steps:
1. Prepare an ice bath (described earlier in this section).
2. Referring to Figure 2, connect the equipment to T1 using K-type thermocouple wire
and a K-type thermocouple connector. Allow the setup to thermally stabilize at least
5 minutes after inserting the thermocouple connector into the thermometer.
3. Turn the thermometer on and select the thermocouple type using the
D, K, N
,
and
Ebuttons.
4. Enter calibration mode (refer to the “A/D Calibration” section, step 2).
5. Using
K or N, select
CAL rEF and press
E.
6. Press
K or N until the upper display matches the known temperature.
Note
Once adjusted, do not change units (
°
C,
°
F, or K) until the thermometer is
in measurement mode.
7. Press the
E button.
8. “ CAL donE ”appears then press
E to store the calibration in memory.
9. To ignore the calibration changes, use the
K or N, and select “
CAL Abrt ” and
press
E.
Using the Offset to Adjust for Variation Between Thermocouples
Use the offset option in the thermometer SETUP mode to adjust the thermometer's
readings for errors of a specific thermocouple. Use the following procedure:
1. Plug the thermocouple into the thermometer input then allow the setup to thermally
stabilize at least 5 minutes.
2. Place the thermocouple in a known, stable temperature environment (such as an ice
bath, lag bath, or a dry well calibrator).
3. Allow the readings to stabilize.
4. In SETUP, change the offset until the primary display reading matches the bath
temperature. (See "Changing Setup Options” in the 51/52 Series II Users Manual,
and the 53/54 Series II Users Manual.)