ThermoWorks 9141 HART SCIENTIFIC FIELD DRY-WELL TEMPERATURE CALIBRATORS - Manual (Page 32)

the user may restore these values to the factory settings. The user should have a
list of these constants and their settings with the instrument manual.
WARNING: DO NOT change the values of the instrument calibration
constants from the factory set values. The correct setting of these parame-
ters is important to the safety and proper operation of the instrument.
The calibration parameters menu is indicated by,
CAL
Calibration parameters menu
Press “SET” five times to enter the menu. The calibration parameters menu
contains the parameters, R
0
, ALPHA, and DELTA, which characterize the re-
sistance-temperature relationship of the platinum control sensor. These parame-
ters may be adjusted to improve the accuracy of the calibrator.
The calibration parameters are accessed by pressing “SET” after the name of
the parameter is displayed. The value of the parameter may be changed using
the “UP” and “DOWN” buttons. After the desired value is reached press “SET”
to set the parameter to the new value. Pressing “EXIT” causes the parameter to
be skipped ignoring any changes that may have been made.
7.9.1 R
0
This probe parameter refers to the resistance of the control probe at 0°C. The
value of this parameter is set at the factory for best instrument accuracy.
7.9.2 ALPHA
This probe parameter refers to the average sensitivity of the probe between 0
and 100°C. The value of this parameter is set at the factory for best instrument
accuracy.
7.9.3 DELTA
This probe parameter characterizes the curvature of the resistance-temperature
relationship of the sensor. The value of this parameter is set at the factory for
best instrument accuracy.
7.10 Operating Parameters
The operating parameters menu is indicated by,
PAr
Operating parameters menu
Press “UP” to enter the menu. The operating parameters menu contains the HL
(High Limit) parameter. The HL parameter adjusts the upper set-point tempera-
29
7 Controller Operation
Operating Parameters