Future Design MCT-MC 4.3, User Manual

Page: 116 / 186

MCT-MC
4.3
FDC MCT-MC - 116 - Offline Setup
Once the calibration offset is complete, press the “Done” button to return to the main Calibration screen.
10.5.2 Manual (Factory) Calibration
The manual calibration procedure is a two step process for RTD and linear inputs and a three step process for
thermocouple inputs. Each step of the calibration procedure can be skipped which provides the user with a
means to exit manual calibration without actually altering the calibration coefficients of the loop control.
CAUTION: Performing manual calibration will replace the factory calibration coefficients with new values.
If calibration is performed incorrectly, it could introduce a large input error resulting in
dangerous operating conditions if not detected or render the device inoperable requiring that it
be sent back to the factory for repair. Prior to calibrating each coefficient, it is recommended
that the current value be recorded. The calibration coefficients can be manually entered so if
the calibration process fails, the previous values can be re-entered returning the unit to its
previous operational state.
10.5.2.1 Thermocouple Input Calibration
When the loop input is configured as a thermocouple input, pressing the “Perform Manual Calibration” button
on the main Calibration screen will begin the thermocouple calibration procedure. The procedure is a three
step process and begins by calibrating the zero of the A to D converter.
To calibrate the input low coefficient, connect the millivolt source to the input terminals of the loop control. Adjust the
source signal to 0mV and allow several seconds for the source signal to stabilize. Record the current calibration
coefficient value. Press the “Calibrate” button to calibrate the input low coefficient. A dialog will be shown indicating
the new coefficient is being calculated. DO NOT alter the source signal during the process. Once complete, the dialog
will close and the new coefficient value will be shown.
If the new coefficient value is -1999 or 1999, the calibration failed. Check the source connections and insure
the proper signal is applied. Press the Calibrate button to repeat the process or press the coefficient
display/entry field and enter the previous coefficient value recorded to return the loop/limit back to its previous
state. To skip the input low coefficient calibration or to proceed to the next step after calibration has been
performed, press the “Next” button.
Step 2 of the procedure is calibrating the span of the A to D converter.
To calibrate the input high coefficient,
connect the millivolt source to the input terminals of the loop control. Adjust the source signal to 60mV and allow several
seconds for the source signal to stabilize. Record the current calibration coefficient value. Press the “Calibrate” button
to calibrate the input high coefficient. A dialog will be shown indicating the new coefficient is being calculated. DO NOT
alter the source signal during the process. Once complete, the dialog will close and the new coefficient value will be
shown.