GE Industrial Solutions POWER LEADER PMCS Network Architecture Guide - Manual (Page 52)

Power Management Control System
Chapter 4 – Trouble-Shooting
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Chapter 4 –Trouble-Shooting
This chapter presents basic trouble-shooting procedures
for PMCS networks. It is not meant to be a comprehensive
guide covering every possible contingency, but will help to
resolve the most common difficulties. If the information
presented here does not resolve the problem, contact a
Resolution Engineer at the GE Resolution Center, at 1-888-
GE-RESOLV.
4–1 Communication Network Trouble-Shooting
One of the most useful tools for trouble-shooting network
problems is a one-line diagram. The following procedure
uses such a diagram.
1. Obtain a one-line diagram of the system.
2. Verify that none of the Modbus network
configuration rules, detailed in Chapter 2, have
been violated.
3. If POWER LEADER commnet IEDs are attached to
the network via Modbus Concentrators, you must
check their configuration as well. Examine each
Concentrator and its attached commnet IEDs to
verify that none of the commnet network
configuration rules detailed in Chapter 2 have been
violated.
If the network complies with these rules, or has been
modified to comply with them, and problems persist,
continue with the remaining steps.
4. Determine if any communication is possible. Select a
Modbus IED whose wiring connections you have
checked from the host to the IED and attempt
communication from the host to the IED. If no
communication can be established, check that the
communication settings for the RS-485 network
match those set at the IED and that the Modbus
address at the IED matches the address assigned at
the host. Reattempt communications.
Communication with an IED connected to an RS-
485 network requires that it have a Modbus address.
Addresses are assigned during IED setup. After the
IED address has been assigned, it must be entered
into the host computer. Commnet IEDs must be
assigned Modbus-equivalent addresses at the
Modbus Concentrators and commnet addresses at
the IED. Refer to each IED’s instruction manual for
detailed procedures. When the address is entered at
the host, the host will attempt to communicate with
the IED. If communication can be established with
some IEDs, continue with step 5; otherwise, go to
step 6.
5. Establish a pattern for the IEDs that do not respond.
Are all the IEDs with problems Modbus IEDs? Are
they all commnet IEDs? Are they all on one RS-485
network or a single commnet segment, or are they
located on different networks or segments? Do all
the IEDs on a segment up to a certain point
communicate, while IEDs after that point do not?
If communication cannot be established with any of
the IEDs on a network, go to step 7.
6. If the error is limited to certain IEDs, the following
checklist should help you isolate the problem.
• The IED is powered up.
• The IED’s communication settings match those
of the network it is on (baud rate, parity, stop
bits).
• The IED’s address has been assigned.
• The same address is not assigned to another IED.
• The network connections are good.
7. If the network has no repeaters, go to step 8.
For commnet segments with Repeaters, you can
localize the problem by checking all repeaters for
red LEDs, which indicate disabled segments. Each
repeater should have one LED lit on each input and
output (either red or green). If more than one LED
is lit or if none of the LEDs are lit, refer to the
trouble-shooting section of the repeater manual.
NOTE: If other IEDs are connected to the
segment, the status LEDs may glow dimly when
the cables are connected, even though the
POWER LEADER Repeater is not powered.