Controls & Internal Indications 5
Man-1453 Rev.01
Sigma ZXT SI Product Manual
13
Processor and Watchdog Reset Switches
The status unit is controlled by a microprocessor, which will re-start itself and continue to run if it stops.
To ensure that the unit is not being subjected to continual, undue interference which may effect its proper operation,
a CPU fault indicator is latched on and a fault condition signalled to the Control Panel.
If a processor re-start has occurred, this latched fault condition will need to de reset by pressing the WDOG RESET
button on the bottom of the PCB.
A switch is also provided to manually re-start the processor PROC RESET. This switch can be used while connected
to the system to ensure that unit starts and establishes communication with the Panel in a controlled and expected
manner.
Figure 5-4
Processor and Watchdog Reset Switches
Internal LED Indicators
An extinguishant fault indication at the Control Panel may mean that there are faults at one or more status units. The
status unit fault indications are located along the bottom of the PCB and are as follows:
COM
This LED indicates that the data communications connection to the control panel is not present. This may be be-
cause the data lines are connected with reverse polarity or are not connected. Check RS485 IN and OUT connec-
tions.
HOL
This LED indicates that the HOLD input is open or short circuit. Check that the correct end of line resistor is con-
nected to the HOLD terminals or at the end of the wires connected to the HOLD input and that the HOLD input is
not short circuited.
IMPORTANT NOTE: When there is a fault on the HOLD input then the HOLD function is invoked which means that
the extinguishant release will not operate until this condition is cleared.
MOD
This LED indicates that the MODE input is open or short circuit. Check that the correct end of line resistor is con-
nected to the MODE terminals or at the end of the wires connected to the MODE input and that the MODE input is
not short circuited.
FUSE
This LED indicates that the electronic fuse has operated. Under this condition, the status unit is not operational. This
may be due to incorrect polarity of the power connection or a failure on the unit itself.
Processor Reset
Watchdog Reset
