Liebert AC4 User Manual
Page 11
Introduction
5
I - Digital output
loss-of-power
jumper
One of four output jumpers. Each digital output has a
jumper to set the fail-safe position of the output point when
power fails. The OFF position makes the contact Normally
Open (factory default). The ON position makes the contact
Normally Closed.
Note: The jumper position has no effect on the contact
when the AC4 has power.
3.2.3: Setting the Digital Output
7.6.4: Configure Output for Loss of
J - Digital input
connectors
Each of the four input connections is a two-state point: ON/
OFF (energized/de-energized).
An example of a field digital input is a Liebert
Environmental unit’s common alarm relay output.
3.2.1: Connecting Digital Inputs
5.4:
K - Digital input
status LEDs
Each input has an LED to indicate its status: ON/OFF
(energized/de-energized).
L - Serial interface
connector (RS232/
EIA574)
Connection for laptop or video terminal. Used for
configuration and monitoring using the Service Terminal
Interface. Requires a null modem cable for connectivity
(P/N 201258P1).
A.2: Connecting to the Service
DIP switch used for resetting password to default.
Connection for the LCD on the enclosure door.
N/A
Adjustment contrast for the LCD on the enclosure door.
N/A
Power connection for the controller. Requires 24VAC.
Table 1
Controller board components (continued)
Item
Description
For more information, see: