Calibration
The Calibration High and Calibration Low selections are accessi- ble only when the calibration jumper is installed (Figure 6).
Calibration 
,
Calibration of the OTC25 controller requires the operator to apply two separate fixed and specific signals (Calibration Low and Calibration High) from a reference source (thermocouple calibrator) to the controller. The Raise 
Key “tells” the controller to read the applied signal and use it as a reference point.
Figure 6. Location of Calibration Jumper.
Calibration Procedure
1.Prior to applying power to the unit, install the calibration jumper on the microprocessor board as shown in Figure 6.
2.With the instrument still unpowered, connect a calibration reference source to the thermocouple input terminals on the OTC25.
3.Apply power. Allow at least 15 minutes for the controller to warm up before continuing.
4.Using the Parameter 
Key, index to the Calibration Low
parameter. The display will alternately flash this mnemonic and the number “32” (“0” for Celsius units).
5.Adjust the reference source to output a voltage equivalent to that generated by a “J” or “K” (OTC25 P) thermocouple at 32° F (0° C). Allow reference to settle for 10 seconds before proceeding.
6.Press the Raise key 
once to set this reference point. The display will stop flashing momentarily while the controller
7.Press the Parameter 
Key, index to the Calibration High
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