Fluke 1551A Ex Calibration Manual

1551A Ex/1552A Ex
Calibration Manual
8
At each calibration point the measurement error may be calculated by subtracting the
reference thermometer temperature from the 1551A Ex/1552A Ex temperature. The
temperatures and measurement errors may be recorded in Table 5.
Table 5. As-found Measurement Errors
Point Reference (fill in) 1551A Ex/1552A Ex (fill in) Error (fill in)
1
2
3
4
5
If the measurement errors are well within the specified accuracy, it may not be necessary
to adjust the calibration parameters. If the error is larger than desired (say 50 % of the
specified accuracy), then adjustments to the Product calibration parameters are necessary.
Proceed to the next section.
Adjustment at the Low Calibration Point
When necessary, the first adjustment is made for the low end of the temperature range of
the Product. Set the bath temperature to the Low Adjustment Temperature given in Table
6, depending on the model. Make sure the temperatures of the bath, reference
thermometer, and Product are settled and stable before proceeding.
Table 6. Low-Adjustment Temperature
Point 1551A Ex 1552A Ex
Low −50 °C −80 °C
Before adjustments to any calibration parameters can be made, access to the protected
calibration parameters must be enabled by sending the following command to the Product
through the serial interface:
SYST:PASS:CEN <password>
The parameter <password> is the current password, originally “1234”.
To make an automatic adjustment at the low calibration point, issue the following
command:
CAL:USER:LOW <temperature>
The parameter <temperature> is the temperature of the bath as measured by the reference
thermometer. Product accepts a temperature value with up to three decimal places of
resolution. The temperature value must be in the same unit in which the 1551A
Ex/1552A Ex is measuring.
The command will set the value of the CAL:USER:TEMP1 parameter to the given
temperature and automatically adjust the CAL:USER:ADJ1 parameter to cause the
Product to measure the given temperature accurately. The adjustment made here will not
affect the measurements at the other Adjustment temperatures.
Allow the readings of the Product to settle and then verify that the readings match the
temperature of the reference thermometer and are well within the specified accuracy of
the 1551A Ex/1552A Ex.

Fluke 1551A Ex Specifications