Liebert AC4 User Manual

3.2.2 Connecting Digital Outputs
The four digital outputs are found on the lower right side of the Liebert AC4 just above the input terminal
blocks, as shown at right. These outputs are numbered 1 through 4.
To connect an output:
1. Turn OFF electrical power to the Liebert AC4.
2. If necessary, remove a conduit knockout to permit wire entry into the Liebert AC4 enclosure.
3. Bring the wire(s) into the Liebert 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.
NOTE: To reduce the risk of fire or electric shock, do not interconnect the outputs of different class2
circuits.
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 Liebert
AC4 in a fail-safe mode and ensures proper functioning
when the board has no power.
The Liebert 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 (normally closed). The settings are shown in Table 3.2
below.
Setting
Output status
(power loss)
OFF Normally open
ON Normally closed
Table 3.2
Digital output jumper settings
To change the output jumper setting:
1. Find the respective loss-of-power jumper on the circuit board, as shown above. See Controller
board components on page11 for more information.
2. Decide whether your configuration requires the jumper to be OFF or ON.
Vertiv | Liebert® AC4 User Manual | 23

Liebert AC4 Specifications

General

Brand	Liebert
Model	AC4
Category	Control Unit
Language	English