Honeywell UMC800 - Manual (Page 75)

Maintenance
Controller Calibration
Release F UMC800 Controller Installation and User Guide 67
4/01
Field calibration
Field calibration of controller components is limited to AI modules and AO modules. Individual channels
of the modules can be calibrated at 0% and 100% of their range. Individual channels can be calibrated at a
single point within the range through zero offset (bias) adjustment.
Calibration procedures
Calibration routines are initiated from either the operator interface or a PC running the user utility program
by first placing the controller in the Program or Offline mode. This can be done manually at the Controller
or through the Calibration displays. Calibration displays are accessed from the UNIT SETUP display of the
operator interface or under the Maintenance menu of the user utility.
Refer to the UMC800 Operator Interface User Guide and the UMC800 User Utility User’s Guide for
details on these and other calibration procedures.
AI module calibration
Selecting the CALIBRATE AI lists a number of calibration functions you can perform.
Selecting the CALIBRATE AI CHANNEL allows you to specify the AI module and channel in which to
calibrate. When you Select Input, you must apply a 0% reference value to the terminal block of the module
channel. See Figure 33 for terminal connection points. Then select Calibrate 0% Input to start the
calibration routine. After calibration of 0% value is completed, apply a 100% range value to the channel
input terminals and then begin the calibration routine for 100% input.
ATTENTION
Handheld calibrators do not work with the UMC800 when calibrating RTDs because they are
resistance simulators with active components, not actual resistors.
When 100% range value calibration is completed, the controller compares the new 0% and 100% range
values against the current 0% and 100% values. If the span of the 0% and 100% readings is less than 20%
of the sensor range, the new values are rejected and the current calibration is retained.