Emerson 475, User Manual

Page: 74 / 114

Troubleshooting 5-4
Table 5-2. Troubleshooting Table for the Fieldbus Protocol
Symptom Possible Causes Solution
No communication
with device. The Field Communicator
is connected to a
segment with DeltaV and
the device on the same
segment is being
commissioned using
DeltaV. The Field Communicator is unable
to communicate with this device
until you go offline and then back
online.
Connected to a
segment in a bench
configuration and the
Live Device List
remains blank (even
the Field
Communicator does
not appear). This issue is caused by
the speed at which
certain LAS-enabled
devices are attempting to
run the segment. Establish communication by
putting the Field Communicator on
the segment first and then adding
one or more devices. By putting
the Field Communicator on first, it
will remain the LAS and control the
communication.
Unable to change the
address of a device. The Field Communicator
is unable to change the
address of a device that
is currently the LAS. Establish communication by
putting the Field Communicator on
the segment first and then adding
one or more devices. By putting
the Field Communicator on first, it
will remain the LAS and allow the
address change.
The Field
Communicator does
not remain the LAS
on a segment. A host takes over as the
LAS. When a host is established on a
segment, it will take over as the
LAS. No action is required.
A backup LAS takes over
as the LAS. The lower the
address and Slot Time of
the device, the more
likely this will occur. See “Changing the Slot Time” on
page 4-16.