MAN0443.P65 Issue 13 Aug 04
CHAPTER 2 - SYSTEM DESCRIPTION
Single Channel Control Card
The Single Channel Control Card carries out the control functions for a
single loop of gas detection as follows:
Processes the incoming sensor drive module signal.
Displays the signal level on the front panel liquid crystal display.
Compares the signal level with pre-defined alarm limits.
When the pre-defined alarm limits are exceeded, raises the alarms
by lighting up front panel LEDs and operating optional connected
Informs other cards with the alarm status information.
Self validates the operation of its circuit components, software
operation and the condition of the sensor.
Sensor Drive Modules
Two sensor drive modules are provided:
Sensor Drive Module, 4 - 20mA,
Sensor Drive Module Catalytic,
The Sensor Drive Module conditions the incoming catalytic or 4 -
20mA sensor signal and provides the necessary sensor power supply.
It contains all the circuitry necessary to generate the voltages and
currents required to drive the sensor, the circuitry to acquire the
sensor signal and to scale the sensor signal to a standard output. The
sensor drive modules are factory fitted and plug directly onto the
channel control card.
Analogue Output Module
An optional Analogue Output Module, (Part Number 05701-A-0285),
may be factory fitted to the Single Channel Control Card and is used
on a channel of gas detection to provide an isolated current loop
output which follows the sensor signal level. This may be set
electronically to produce a 0 - 20mA output or a 4 - 20mA output and
can be used to operate a chart recorder, etc.
Part Number 05701-A-0283
Part Number 05701-A-0284
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5701 Control System