GasSens
Gas Detection System
Section 2 - A14 Receiver Module
O & M Manual
A14-RK, 8/06
2 - 7
Relays may be configured for either Fail-safe or Normal operation. The designation of normal
or fail-safe refers to the operation of the relay coil during normal operation. A relay configured for
Normal operation will have the relay coil energized when an alarm occurs and de-energized during
normal operation. A relay configured for Fail-safe operation has the relay coil energized when
conditions are normal and de-energizes when an event occurs. A fail-safe relay will change state
if power to the receiver is interrupted.
A short time delay precedes the activation of warning and alarm relays when a setpoint is
exceeded. This brief delay of 2 seconds eliminates false alarms due to transients that might be
encountered in a particular installation. The 2 second delay is the factory default and is selected
with switch B1. A 10 second delay may be selected if required in a specific application. The delay
time of either 2 or 10 seconds affects both the warning and alarm indicator lamps and the
associated relays.
External Horn Relay
Relay 3 provides an additional configuration option not available on relays 1 or 2. Switch C5
allows relay 3 to be configured for use in activating an external audible horn. When switch C5 is
on, relay 3 will operate in parallel with the internal horn. This means that any external horn tied to
that relay will sound intermittently when the warning setpoint is exceeded and will go to steady on
when the alarm setpoint is exceeded. The relay will deactivate when the
A/R
switch is pressed,
silencing the external horn.
Using relay 3 in the horn configuration eliminates the need for additional relay logic to silence
an external horn. This can provide significant cost savings in the installation of a complete alarm
system.
Display Intensity
The LED display on the receiver will operate in either normal or high intensity mode. The
factory setting is normal mode. Switch D2 is used to select high intensity mode for outdoor
installations.
