Watlow EZ-ZONE PM Integrated Controller - Manual (Page 129)

Watlow EZ-ZONE ® PM Integrated Controller • 126 • Chapter 9 Features
Note:
The user may only calibrate one sensor type. If the calibrator interferences with open thermocouple detec-
tion, set Sensor Type [`SEn] in Setup Page [`SEt], Analog Input Menu [``Ai] to millivolt [`Mu] instead
of Thermocouple [``tC] to avoid interference between the calibrator and open thermocouple detect circuit
for the duration of the calibration process. Be sure to set sensor type back to the thermocouple type utilized.
1. Disconnect the sensor from the controller.
2. Record the Calibration Offset [`i;CA] parameter value in the Operations Page [oPEr] , Analog Input
Menu [``Ai] then set value to zero.
3. Wire the precision source to the appropriate controller input terminals to be calibrated. Do not have any
other wires connected to the input terminals. Please refer to the Install and Wiring section of this manual
for the appropriate connections.
4. Ensure the controller sensor type is programmed to the appropriate Sensor Type [`SEn] to be utilized in
the Setup Page [`SEt] , Analog Input Menu [``Ai].
5. Enter Factory Page [FCty] , Calibration Menu [`CAL] via front panel or EZ-ZONE Configurator
Software.
6. Select the Calibration [CAL] input instance to be calibrated. This corresponds to the analog input to
be calibrated.
7. Set Electrical Input Slope [ELi;S] to 1.000 and Electrical Input Offset [ELi;o] to 0.000 (this will
cancel any prior user calibration values)
8. Input a Precision Source Low value. Read Electrical Measurement value [`Mu] of controller via
EZ-Configurator or RUI. This will be referred to as Electrical Measured Low. Record low value
______________
9. Input a Precision Source High value.
10. Read Electrical Measurement value [`Mu] of controller via EZ-Configurator or RUI. This will be re-
ferred to as Electrical Measured High. Record high value ______________
11. Calculated Electrical Input Slope = (Precision High – Precision Low) / (Electrical Measured High - Electri-
cal Measured Low) Calculated Slope value ___________
12. Calculated Electrical Input Offset = Precision Low - (Electrical Input Slope * Measured Low) Calculated
Offset value ___________
13. Enter the calculated Electrical Input Slope [ELi;S] and Electrical Input Offset [ELi;o] into the controller.
14. Exit calibration menu.
15. Validate calibration process by utilizing a calibrator to the analog input.
16. Enter calibration offset as recorded in step 2 if required to compensate for sensor error.
Setting Electrical Input Slope [ELi;S] to 1.000 and Electrical Input Offset [ELi;o] to 0.000, restores factory
calibration as shipped from factory.
Filter Time Constant
Filtering smoothes an input signal by applying a first-order filter time constant to the signal. Filtering the
displayed value makes it easier to monitor. Filtering the signal may improve the performance of PID control
in a noisy or very dynamic system.
Adjust the filter time interval with Filter Time [`FiL] (Setup Page, Analog Input Menu). Example:
With a filter value of 0.5 seconds, if the process input value instantly changes from 0 to 100 and remained at 100,
the display will indicate 100 after five time constants of the filter value or 2.5 seconds.
Unfiltered Input Signal
Time
Temperature
Filter Time Constant
Filtered Input Signal
Time
Temperature