Chromalox 3901 User’s Manual
13
Section 4
Calibration
☛
The 3901 controller has been calibrated and tested at
the factory prior to shipment. Calibration on receipt is
not necessary.
Equipment
Required
A precision thermocouple simulator and a small
instrument screwdriver are necessary to calibrate the
controller.
Locating
Calibration
Adjustments
Remove the back cover from the controller as
described on page 4. Figure 4.1 identifies the zero and
span calibration potentiometers.
Zero Potentiometer
Span Potentiometer
➛
Calibration
Procedure
1. Connect the sensor simulator to terminals 7 and 8,
making sure to connect the (+) to 7 and (-) to 8.
2. Set the sensor simulator to a minimum value (200
°
F
for J T/C, 350
°
F for K T/C). While pressing the
“READ TEMP” pushbutton, adjust the zero
potentiometer until the digital display equals the
sensor input value (200
°
F or 350
°
F).
(continued on next page)
Figure 4.1
Zero and Span
Calibration
Potentiometers