Section 13 • Instruments Calibration; Overview; Pressure And Temperature Inputs - Emerson Vilter Vission 20/20 Operation And Service Manual

Section 13 • Instruments Calibration

Overview

The Instrument Calibration screen allows the operator
to defi ne how the Vission 20/20 will interpret the signal
from any devices attached to the panel's analog inputs.
The instrument calibration screen is organized up to six
pages. Each page is then divided into several left side
selected tabs. Each tab will be headed with an informa-
tion bar labeled "I/O" that give the basic information
for that device. The "A/D bit Value" display box shows
the unmodifi ed value read by the Vission 20/20 analog
to digital converters. This display box is not affected by
any changes to the calibrations settings. As long as a de-
vice is connected to the associated input, there will be
a value in this display box. The "Calibrated Value" dis-
play box shows the end result of the calibration process.
Therefore, any changes to the calibration setpoint will
effect what value is shown.
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
Figure 13-1. Instruments Calibration Screen - Analog Inputs (Page 1)
Vission 20/20 • Operation and Service Manual •Vilter/Emerson • 35391SC 1.9
calibrated through the Vission 20/20.

Pressure and Temperature Inputs

The most commonly used instruments are tempera-
ture and pressure sensors. The fi rst two pages of the
Instrument Calibration screen are dedicated to these
instruments, see Figures 13-1 and 13-2.
Each tab on these two pages are divided into two sec-
tions, Device Calibration and Channel Calibration. The
device calibration section is where the operation param-
eters of the instrument is defi ned. The channel calibra-
tion defi nes the type of signal sent by the instrument.
Default Devices:
• By selecting this option, the operator will have access
via a drop-down box of several common devices. The
devices are predefi ned and if one is selected, then all
the setpoints will be set for the operator.
13 – 1