Yokogawa DR240 - Manual (Page 36)

Functions
2-15 IM DR231-01E
2
Operation Mode
Energizing/De-energizing Setting
The alarm output relays can be selected to be energized or de-energized on alarm occurrence.
Using de-energizing, the alarm output relay will be activated when the power drops in the same
way as when an alarm occurs. This setting can be done for each relay individually.
Relay contacts in case of energizing
A-contact
NO C NO C
When power is OFF When power is on
and no alarm has
occurred
When power is on
and an alarm has
occurred
NO C
NO C NO C
When power is OFF When power is on
and no alarm has
occurred
When power is on
and an alarm has
occurred
NO C
C-contact
NO C NC NO C NC NO C NC
When power is OFF When Power is ON
and no alarm has
occurred
When Power is ON
and an alarm has
occurred
Relay contacts in case of de-energizing
NO C NC NO C NC NO C NC
When power is OFF When Power is ON
and no alarm has
occurred
When Power is ON
and an alarm has
occurred
AND/OR Setting
When a group of alarms share the same internal switch or alarm output relay, you can select how
the internal switches/alarm output relays will be operated.
AND: will be operated when all alarms are occurring;
OR: will be operated when at least one alarm is occurring.
Alarm occurrence
Channel 1
AND
Channel 2
Alarm output
relay status
Alarm occurrence
Operation
Operation
OR
Alarm status
HOLD/NON-HOLD Setting
You can select whether to hold the operating status of operated internal switches or alarm output
relays. This setting applies to both the internal switches and the alarm output relays.
Alarm release
Alarm reset
(Refer to page 2-16)
Alarm status
Operation of
Internal switch/
alarm output
relay
Alarm release
Working Working
Reflashing Alarm Setting
When several alarms share the same alarm output relay, you can select this setting which results
in a short de-operation of the relay when a second alarm occurs.
Reflash=ON
Reflash=OFF
Alarm status
Alarm output relay
Channel 1
Channel 2
Channel 3
Approx. 200ms Approx. 200ms
Alarm occurrence
Alarm occurrence
Alarm occurrence
Working Working Working
Working
2.4 Alarm Function