3 setting the digital output jumpers, Table 5 digital output jumper settings, 3 connecting common alarm outputs – Liebert AC4 User Manual

Page 20: 4 rs232 connector, Setting the digital output jumpers, Connecting common alarm outputs, Rs232 connector, Table 5, Digital output jumper settings, Connecting common alarm

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Wiring and Connections

3.2.3 Setting the Digital Output Jumpers

Each digital output has an associated jumper to define its

operation when power is interrupted. This puts the AC4

in a fail-safe mode and ensures proper functioning when

the board has no power.
The AC4 comes from the factory with all digital output

jumpers in the OFF position (normally open). The jumper

setting for each digital output can be changed to ON (nor-

mally closed). The settings are shown in Table 5.

To change the output jumper setting:
1. Find the respective loss-of-power jumper on the

circuit board, as shown above. See Table 1 - Controller board components for more

information.

2. Decide whether your configuration requires the jumper to be OFF or ON.
3. Set the jumper as needed:

• Set the jumper to OFF by placing the loss-of-power jumper on the middle and top pins.
• Set the jumper to ON by placing the black jumper on the middle and bottom pins.

3.3

Connecting Common Alarm Outputs

The common alarm relay, found in the top right corner of the

AC4, permits the user to connect auxiliary notification equip-

ment, such as lights, horns and sirens, to the AC4. To determine

the proper wire size, see Table 4 - Wiring specifications.
There are two connectors for the common alarm output. However,

the connectors are not individual relay outputs. The connectors

should be treated as a double-pole, double-throw (DPDT) relay.
The common alarm relay is energized whenever an alarm occurs.
To connect an output:
1. Turn OFF electrical power to the AC4.
2. If necessary, remove a conduit knockout to permit wire entry into the AC4 enclosure.
3. Bring the wire(s) into the AC4 enclosure through a conduit knockout or access slot.
4. Loosen the appropriate screw and slip the stripped end of the wire into the terminal block.
5. Tighten the screw until it holds the wire snugly.

3.4

RS232 Connector

The AC4’s Service Terminal Interface offers full con-

figuration and monitoring capability via the RS232

port (see A.2 - Connecting to the Service Termi-

nal Interface).
The RS232 port requires a null modem cable. Connect

one end of the cable to the AC4’s RS232 port, shown

at right, and the other end to the COM1 port of a lap-