AirLink 7543 Gas Monitor Operator’s Manual
Chapter 1: Introduction • 5
Chapter 1: Introduction
Overview
This chapter briefly describes the AirLink 7543 Gas Monitor. This chapter also describes the
AirLink
7543 Gas Monitor Operator’s Manual
(this document). Table 1 at the end of this chapter lists the
specifications for the AirLink 7543.
About the AirLink 7543 Gas Monitor
The AirLink 7543 can monitor up to 6 WireFree sensors. All configured channels are displayed every
three seconds (scanned). When one channel indicates a gas reading, the monitor locks to that channel.
If two or more channels are indicating a gas reading, the monitor scans those channels every three
seconds. The user can manually scan channels by pressing
ADD
to move forward through channels or
SUB
to move backward through channels. The currently displayed channel will remain on the display
for one minute and then the instrument will return to normal scanning.
There are three 5 Amp relays with 4 Amp fuses. The third relay may be configured as a Fault relay.
This Fault relay will activate if any Fault is generated by the monitor or if any sensor that the monitor
is configured to monitor goes into Fault. The Fault relay is removed from any further configurable
options in Channel Setup—leaving only two relays for each channel. All relays can be configured to be
either latching or auto resetting. The relays can be configured with different set points for alarm
conditions for each channel, allowing each channel to have their own gas level set points.
An optional strobe and/or horn can be ordered. The strobe is installed on the top of the housing and is
wired into the first relay. The horn is installed on the bottom of the housing and is wired into the
second relay.
All relays have a 10% of value of hysteresis on the set points. This prevents the relays from rapidly
switching on and off if gas readings are jumpy. Once the threshold value of a relay is reached, the relay
is activated. However, the AirLink 7543 screen will not lock on the channel with a triggered relay
while the reading is below the Relay Set Point (the user must scroll through the channels to find the
channel with a triggered relay). When the gas reading decreases below the threshold value, the relay
must be 90% of the initial threshold value to deactivate.
