The Liebert AC8 is ideal for coordinated control of systems
with redundant equipment, such as multiple environmental
units or pumps. When the AC8 controller detects an alarm in
an operating device, the AC8 enables a standby device and
controls the device in alarm as configured, either leaving that
device operating or disabling it.
The AC8 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 AC8 can perform routine testing of standby
devices and alert personnel if a standby device fails an
operating test and requires attention.
The staging feature permits standby devices to be turned on
or off when a sensor detects specified levels. For example, the
AC8 might be configured to turn on a fan when the
temperature reaches 75°F, then turn on a second fan at 80°F.
When the temperature falls below 80°F, the second fan is turned off; when it drops below 75°F,
the first fan is turned off. Liebert’s TW420 Temperature Transmitter may be connected to any of
the four analog sensor inputs for staging and other functions.
Another capability of the AC8 is monitoring the status of connected devices and keeping
personnel apprised through local alarming. The AC8 employs local alarming and remote paging
services to keep personnel on-site and at remote locations apprised of the status of equipment.
The AC8 controller can interface with
anything that closes an electrical contact.
To improve process efficiency and
troubleshooting, the controller tracks data
in three types of logs: alarm, event and
trend.
The AC8 has both a local LCD interface
and a remote dial-up interface for
configuration and monitoring. Liebert’s
SiteScan Web may also be used for
monitoring, as well as some configuration
functions.
When an alarm condition arises, the AC8
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. If configured, the controller
also sends pager notifications.
Features and Benefits
• Custom configuration for specific applications
• Paging capability—up to four pager numbers
• Preconfigured on-board modem
• Alarm, Event and Trend logs with time and
date stamp
• Battery backup to ensure alarm notification
• Backup and download configuration files
• User interface via RS232 or modem connection
• On-board audible alarm
• Configuration data permanently stored in nonvolatile Electrically Erasable Programmable
Read Only Memory (EEPROM) for protection
against power loss
• Real-time clock
For other applications, contact your local
Liebert representative or call
1-800-222-5877.
• Status LEDs for verification and diagnostics
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Hardware and Components
BAR CODE
Enclosure
The AC8 comes standard in an enclosure, which
features a key lock for added security. The enclosure
is made of metal to accommodate secure conduit
fittings and protect components against
environmental debris.
AC8 enclosure - External features
Knockouts and
access slots
on top and
bottom
• The enclosure is designed for easy wire routing
and terminations. Access slots for communication
cables and network wires are located on both the
top and bottom of the enclosure.
• The enclosure is 2-3/4" deep, allowing for recess
mounting in a wall. The enclosure may also be
flush-mounted.
• The enclosure houses the controller board and
Transformer Module.
Keypad Display
The keypad is a user interface
mounted on the enclosure door of
the AC8. The liquid crystal display
(LCD) provides for complete
monitoring and configuration of the
panel and is password-protected.
The keypad display provides the ability for the AC8
to operate as a complete standalone panel.
Key
lock
LCD for
configuration
and operation
Keypad
Controller Board
The controller board supports these connections:
• Eight devices, with 1 digital input and 1 digital
output per device
• Up to four zones, with staging for each zone
• Four 4-20mA analog inputs (one sensor per zone)
• Two programmable digital relay outputs
• Two Common Alarm outputs
•One EPOP input
The digital inputs are dry contacts. The analog
inputs are 4-20mA inputs. The digital outputs,
programmable relay outputs and Common Alarm
outputs are Form C contact relays. The Common
Alarm output is one output with two sets of contacts.
The point terminations are made using removable
terminal blocks. This allows for easier access to the
terminators, streamlining the process of connecting
external devices to the AC8.
The controller board is a microprocessor-based
platform for program execution. The firmware may
be easily upgraded at the job site, simplifying the
process of installing new firmware as it becomes
available. Configuration data is stored in nonvolatile
EEPROM to protect against power loss.
An RS232 operator terminal port is included with
each controller board for operator devices such as a
simple CRT terminal or laptop PC.
An integrated on-board modem allows remote access
to the AC8. The modem is factory-configured,
eliminating field configuration and wiring
requirements. An RJ11 phone modem jack is also
included.
An IGM422 connection permits access to Liebert’s
SiteScan Web Enterprise Monitoring System. This
connection allows information and alarms to be
monitored from a centrally located command center.
® Liebert and the Liebert logo are registered trademarks of
Liebert Corporation. All names referred to are trademarks or
registered trademarks of their respective owners.
SL-31101 (12/05) Rev. 0
4
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