Liebert Autochangeover Controllers AC4 - Manual

1
AC4
Product Specification/Installation Sheet
Description
The Liebert AC4 is ideal for coordinated control of systems with
redundant equipment, such as multiple environmental units or
pumps. When the AC4 controller detects an alarm in an
operating device, the AC4 enables a standby device and controls
the device in alarm as configured, either leaving that device
operating or disabling it.
The AC4 controller can also balance usage of devices by rotating
units through Operating and Standby modes according to a user-defined schedule. This helps keep
redundant equipment operating efficiently and only when needed. The AC4 can perform routine
testing of standby devices and alert personnel if a standby device fails an operating test and
requires attention.
Another capability of the AC4 is monitoring the
status of connected devices and keeping
personnel apprised through local alarming.
The AC4 controller can interface with anything
that closes an electrical contact. To improve
process efficiency and troubleshooting, the
controller tracks data in two types of logs:
alarm and event. The AC4 has a local LCD
interface and an RS232 interface.
When an alarm condition arises, the AC4
displays alarm information, sounds an audible
alarm, changes the state of the common alarm
relay and turns connected devices on or off
according to user configuration.
For other applications, contact your local
Liebert representative or call 1-800-222-5877.
Features and Benefits
• Custom configuration for specific applications
• Alarm and Event logs with time and date
stamp
• Backup and download configuration files
• User interface for configuration and
monitoring via local LCD or RS232 port
• On-board audible alarm
• Configuration data and operating program
permanently stored in nonvolatile
Electrically Erasable Programmable Read
Only Memory (EEPROM) for protection
against power loss
• Real-time clock
• Status LEDs for verification and diagnostics
Digital output connectors
Digital input connectors
24VAC power connector
Digital output status LEDs
Digital output loss-of-power
jumper
Manual Override Switch
(outputs)
Status LEDs
Power On/Off switch
LCD connector
Digital input status LEDs
LCD contrast
adjustment
DIP switch 1
Common Alarm connectors
Audible horn
jumper
Audible horn
Serial interface connector
(RS232/EIA574)
AC4 Components and Key Features