7.10
Calibration Parameters
CAUTION:
Care should be exercised when adjusting these parameters as
they affect the accuracy of the set-point. This procedure is explained in de-
tail in Section 9.
The calibration parameter 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, DELTA, BETA, and the integral time ad-
justment which characterize the resistance-temperature relationship of the plati-
num control probe.
These parameters may be adjusted by an experienced user to improve the accu-
racy of the controller.
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” will cause the parameter
to be skipped ignoring any changes that may have been made.
7.10.1
R0
This calibration 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.
7.10.2
ALPHA
This calibration 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 instru-
ment accuracy.
7.10.3
DELTA
This calibration parameter relates to the second order nonlinearity of the sensor.
The value of this parameter is set at the factory for best instrument accuracy.
7.10.4
BETA
This calibration parameter relates to the higher order nonlinearity of the sensor
below 0°C. The value of this parameter is set at the factory for best instrument
accuracy.
2200 Temperature Controller
User’s Guide
30
