Section 8 • Instruments Calibration Overview; I/O; Pressure & Temperature Inputs; Device Calibration - Emerson VILTER MicroVission Operation And Service Manual

Section 8 • Instruments Calibration
Overview
The Instrument Calibration screen allows the operator
to define how the MicroVission will interpret the signal
from any devices connected to panel's analog inputs.
The Instrument Calibration screen is organized in six
pages. Each page is then divided into individual tabs
for every device. Each tab has section labeled "I/O" that
provides the basic information for that device. The "A/D
bit Value" field displays the unmodified value read by
MicroVission analog to digital convertors. This value is
unaffected by any changes to the calibration settings. If
a device is connected to the associated input, there will
be some value displayed in this field. The "Calibrated
Value" field displays the result of the calibration process.
Therefore, any changes to the calibration setpoints will
affect what value is shown. Calibrated value for Pressure
& Temperature values will be displayed in pressure / tem-
perature unit as configured in Configuration Screen.
All instruments are calibrated using a two-point linear
calibration process. Any device that has a non-linear re-
sponse to environmental stimuli will not be able to be
calibrated through the MicroVission.

I/O

Each tab has this section that provides basic information
for that device.
A/D bit Value
This field displays the actual value read by MicroVission
analog to digital convertors. This value is unaffected by
any changes to the calibrations settings. If a device is
connected to the associated input, there will be some
value displayed in this field.
Calibrated Value
This field displays the calibrated value which is the result
of the calibration process. Calibrated value for Pressure
& Temperature values will be displayed in pressure / tem-
perature unit as configured in Configuration Screen.
All instruments are calibrated using a two-point linear
calibration process. Any device that has a non-linear re-
sponse to environmental stimuli will not be able to be
calibrated through the MicroVission.
MicroVission Controller • Operation and Service Manual • Emerson • 35391MV 1.3
Pressure & Temperature Inputs
The most used Instruments are pressure and tempera-
ture sensors. The first two pages of the Instrument
Calibration Screen are dedicated to these Instruments;
see Figure 8-1 up to Figure 8-8.
Each tab on these two pages are divided into two sec-
tions, Device Calibration and Channel Calibration.

Device Calibration

The Device Calibration section is where the operation
parameters of the Instrument are defined.
Default Devices
By selecting this option, the operator will have access
to several common devices via a drop-down list. The
devices are predefined and if one is selected, then all
the setpoints will be set for the operator.
Custom Device
This option allows the operator to choose the minimum
and maximum value of the Instrument being used.
The Instrument Calibration screen provides a set of rang-
es for default devices. You must select an appropriate
range to calibrate the sensor. If you do not find a correct
range, you can specify the custom range.
Based on the calibration range that you select or specify,
the MicroVission displays the calibrated value. This cali-
brated value of the respective analog input is also shown
on the Main screen.

Channel Calibration

The Channel Calibration section defines the type of sig-
nal sent by the Instrument.
Offset
Once the two-point calibration is completed, it is com-
mon for a small error to exist. By entering the value of
the error from the calibrated value and the actual value
into the "Adjustment" entry box, that error will be add-
ed/subtracted from the "Total Offset". The offset is ap-
plied to the calibrated value which should correct the
error.
Range
This option is available when the "Custom Device" op-
tion is selected. Here the operator defines the signal
type and range transmitted by the Instrument. The op-
erator can select from several predefined ranges in the
drop-down list or enter a value.
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