Chapter 2: Operation
14
ZP3-ECU Extinguishing Control Unit User Guide
The Hold Off Extinguishant Release button
The ECU provides a means of ensuring evacuation. There are four modes of
operation, which are selected by switch settings on switch SWT3 on the
Extinguishing Unit’s main board.
See Figure 5 below for an illustration showing the default switch settings of
SWT3 and refer to Table 1 below for a description of the switch functions.
Figure 5: SWT3 default setting
Table 1: SWT3 Switch Functions
Switch Default Function
1
ON
There are two extinguishant discharged report mechanisms.
When switch 1 is ON (default setting), the ECU panel senses an
exstinguishant release by way of its internal circuitry and by way of a remote
sense resistor, external monitor is connected to TB1, pins 17 and 18 on the
ECU main board.
When switch 1 is OFF, the ECU only reports an extinguishant discharge if the
external monitor resistor is short-circuited.
2
OFF
When switch 2 is OFF, the ECU has a time delay before exstinguishant is
released, if triggered by way of an automatic trigger. An automatic trigger is a
trigger mapped to the configured ECU addresses. Automatic delay is set by
potentiometer RV1 on the ECU main board. The delay time factory default
setting is 30 seconds.
When switch 2 is ON there is no delay in response to an automatic trigger.
3
ON
The hold off delay switch configures the operation of the button labeled
‘DEPRESS TO HOLD OFF EXTINGUISHANT RELEASE’ on the ECU front
panel.
When switch 3 is ON and switch 4 is OFF, the ECU delay time countdown is
reset each time the button is pressed. There is no limit to the amount of times
this function can be used. The hold off extinguishant release function settings
on the ECU Main Board are applicable to automatic release mode ONLY.
Note that manual release settings are set by way of links on the ECU display
board. Automatic release delay for mapped trigger is set by potentiometer
RV1 on the ECU Main Board. The factory default delay time setting for
automatic delay is 30 seconds. This switch setting is used together with switch
4 (see below). Switch 3 OR 4 must be ON (depending on the hold off release
operation required).
