9
UK
4.6 Operating mode: 3-wire temperature transmitter with dia-
gnostic switching output
4.6.1 Availability groups in 3-wire operation [drEd]
Types of diagnostic to be signallled via the current or diagnostic switching output
can be set using [drEd] (setting via FDT service program)�
Since in 3-wire operation all diagnostic messages can be transferred via
the switching output, the current output only leaves its process value trans-
fer in case of a failure� This ensures maximum use of the analogue output�
Table 3 Availability groups in 3-wire operation
[drEd]
Warning Alarm Failure
= [ON]
Maximum availability
OU2
(current output)
●
OU1
(switching output)
●
= [ONdr]
High operational reliability
at good availability (factory
setting)
OU2
(current output)
●
OU1
(switching output)
●
●
= [OFF]
Maximum sensor sensitivity
OU2
(current output)
●
OU1
(switching output)
●
●
●