Instruction manual

46 JUPITER CM-4400 Control Module Installation and Operating Manual

Section 2 — Hardware Installation

Alarms in a Single CM-4400 Installation

If the master alarm is asserted by the main CPU watchdog timer (and

assuming that the power supply is operating properly), the CM-4400 will

be rebooted automatically.

Alarms in a Redundant CM-4400 Installation

For additional protection, a redundant CM-4400 can be installed. The

redundant CM-4400 will monitor the master CM-4400.

If a master alarm condition is detected

in the master unit, control will be

switched to the redundant CM-4400 automatically. The switch over to the

redundant unit will occur almost immediately after the alarm, thus pro-

viding minimal disruption to the contr

ol system. The controlling CM-4400

is indicated by a green light on the CM’s

Activate button (see Figure 2 on

page 32).

If the redundant CM-4400 is controlling the system and enters an alarm

ondition and then reboots:

• The redundant CM-4400 will retain control if the master has not recov-

ed.

• The master CM-4400 will assume control if the master has recovered

from an earlier automatic reboot.

Manually Switching A CM-4400

To manually change the operation from the master CM-4400 to the redun-

dant CM, press the

Activate button on the front panel of the redundant CM.

To return operation to the master CM, press the

Activate button on the

master CM.