Hitachi L2002 - Manual (Page 188)

Using Intelligent Output Terminals
Oper
ations
and Monitor
ing
4–44
The alarm relay output can be configured in two main ways:
• Trip/Power Loss Alarm – The alarm relay is configured as normally closed
(C036=1) by default, shown below (left). An external alarm circuit that detects broken
wiring also as an alarm connects to [AL0] and [AL1]. After powerup and short delay
(< 2 seconds), the relay energizes and the alarm circuit is OFF. Then, either an inverter
trip event or an inverter power loss will de-energize the relay and open the alarm
circuit.
• Trip Alarm – Alternatively, you can configure the relay as normally open (C036=0),
shown below (right). An external alarm circuit that detects broken wiring also as an
alarm connects to [AL0] and [AL2]. After powerup, the relay energizes only when an
inverter trip event occurs, opening the alarm circuit. However, in this configuration, an
inverter power loss does not open the alarm circuit.
Be sure to use the relay configuration that is appropriate for your system design. Note
that the external circuits shown assume that a closed circuit = no alarm condition (so that
a broken wire also causes an alarm). However, some systems may require a closed
circuit = alarm condition. In that case, then use the opposite terminal [AL1] or [AL2]
from the ones shown.
N.C. contacts (C036=01) N.O. contact (C036=00)
During normal operation When an alarm occurs
or when power is OFF During normal operation
or when power is OFF
When an alarm occurs
AL0 AL2 AL1
Power
supply
Alarm
device
AL0 AL2 AL1
Power
supply
Alarm
device
AL0 AL2 AL1
Power
supply
Alarm
device
AL0 AL2 AL1
Power
supply
Alarm
device
Power
Run
Mode
AL0–
AL1
AL0–
AL2
ON Normal Closed Open
ON Trip Open Closed
OFF — Open Closed
Power
Run
Mode
AL0–
AL1
AL0–
AL2
ON Normal Open Closed
ON Trip Closed Open
OFF — Open Closed