64
Technical Manual
|
Dräger Polytron
®
8000 Series
Instrument settings
Relay configuration: Normally energized
Relay configuration: Energized on alarm
12.9.3
Examples for relay contacts and configuration
This chapter shows examples for the combination of the connected relay contact
and relay configuration depending on the relay status.
The terminology for contacts, configuration and status is similar and can be
confusing.
Relay contacts
Designation of relay contacts to which an alarm indicator is connected.
– Normally Open (NO)
– Normally Closed (NC)
– Common (COM)
Relay configuration
Behavior of the relay during operation.
– Normally Energized
– Energized on alarm
Relay status
Status of the relay coil during operation.
– Energized (Common terminal connects with Normally Open contact)
– De-Energized (Common terminal connects with Normally Closed contact)
Contact
Alarm indicator status and fault indication by the alarm
indicator
Alarm triggered
Transmitter-spe-
cific fault
Field wiring fault
Normally Closed
ON
indicated
not indicated
Normally Open
OFF
indicated
indicated
Contact
Alarm indicator status and fault indication by the alarm
indicator
Alarm triggered
Transmitter-spe-
cific fault
Field wiring fault
Normally Closed
OFF
not indicated
indicated
Normally Open
ON
not indicated
not indicated