ircon Modline 4, Installation And Operation Manual

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Section
2
– IN
STALLATION
2.1 INTRODUCTION
MODLINE 4 gives you the capability of building a
custom-made temperature monitoring system for
your process, If you follow the simple guidelines
described in this section, you system will give
accurate, trouble free service.
The MODLINE 4 is compatible with most 4 to 20
mA devices used in industry today. You can select
a variety of indicators, recorders and other devices
to complete your system. Combine these devices
in series if you like or combine groups of MODLINE
4’s and switch them manually or automatically to
monitor key checkpoints in the process. As long
as your system stays within the MODLINE 4 speci-
fications, you will get good results. Most of the
descriptions are based on the use of optional
IRCON components. However, the descriptions
also apply to any other devices that are compatible
with the MODLINE 4 system.
- Model PS
4
-
2
4 Power Supply
- TV-VIEW-VAAC Digital Indicator
Power Supply
2. 2 BASIC SYSTEM
Fig. 2.1 illustrates a simple system consisting of the
MODLINE 4, a Digital Meter and a Power Supply.
These components form a continuous current loop.
System power is provided by the Power Supply which
provides a DC output typically between 16 and 40 V
direct current. AC line voltage is used to operate
to operate the supply.
Loop current is determined by the MODLINE 4 which
is calibrated to provide a 4 to 20 mA output. this
current flows through all series loop components.
It varies with target temperature over the full
temperature span of the instrument. For example,
an instrument with a temperature span of 500 to
1500°F will have a 4 mA output when viewing a
500°F target. The output increases to 20 mA when
viewing a 1500°F target. The output is a linear
16 mA span, from 4 to 20 mA, over the instrument
temperature range as illustrated in the Fig. 2.1 curve.
2-1
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