Emerson 375 User Manual page 91

Troubleshooting
Table 5-2. Troubleshooting table for the fieldbus protocol
Symptom
No communication with
field device.
Connection to a segment in
a bench configuration and
the Live Device List
remains blank (even the
375 Field Communicator
does not appear).
Unable to change the
address of a device.
The 375 does not remain
the LAS on a segment.
Possible Causes
The 375 is connected
to a segment with
DeltaV, and the device
on the same segment
is being commissioned
using DeltaV.
This issue is caused by
the speed at which
certain LAS-enabled
devices are attempting
to run the segment.
The 375 is unable to
change the address of
a device that is
currently the LAS.
A host takes over as
the LAS.
A backup LAS takes
over as the LAS. The
lower the address and
Slot Time of the
device, the more likely
this will occur.
Solution
The 375 is unable to communicate with this
device until you go offline and then back
online.
Establish communication by putting the 375
on the segment first and then adding one or
more devices. By putting the 375 on first, it
will remain the LAS and control the
communication.
Establish communication by putting the 375
on the segment first and then adding one or
more devices. By putting the 375 on first, it
will remain the LAS and allow the address
change.
When a host is established on a segment, it
will take over as the LAS. No action is
required.
See "Changing the Slot Time" on page 4-21.
5-5