GE Industrial Solutions POWER LEADER ModBus Monitor - Manual (Page 43)

POWER LEADER Modbus Monitor
Chapter 6 – Troubleshooting Guide
37
Chapter 6
Troubleshooting Guide
The following guide is provided for trouble-shooting and
isolating common problems. It does not cover every
possible condition. Contact a GE Resolution Engineer at
1-888-GE-RESOLV if the problem persists.
Symptom Possible Cause Corrective Action
1. Display blank Lack of power
Internal failure in Modbus Monitor
Check that power wires are correctly connected. Measure
voltage by probing directly on the control power terminal
screws.
WARNING:
Voltages hazardous to personnel and equipment may be
present at the power connection.
Remove and reapply power to the Monitor to see if the
failure clears itself (possibly caused by external noise).
Note the contents of the display and contact the GE
Resolution Center if the problem persists.
2. Communications not
functioning correctly;
devices not recognized or
excessive
communications errors. Faulty RS-485 wiring between
Modbus Monitor and Modbus
devices.
Modbus master malfunctioning or
off.
RS-232/RS-485 converter in use
but not configured correctly.
Invalid Monitor network
architecture is in use.
Network wiring may require
additional capacitance.
Check that the RS-485 connectors are properly wired and
firmly seated. Are + and - connections reversed? Test
wiring for continuity and polarity to the Modbus master.
Check status of the Modbus master and verify attempted
communications to the Modbus Monitor.
Check RS-232/RS-485 converter setup to be sure that
configuration is correct. The baud rate set at the converter
must match the Monitor’s baud rate.
Verify that the wiring for the networks connected to the
Modbus Monitor matches one of the four valid
architectures described in Chapter 2.
(Non-PMCS systems only.) Replace the 120-ohm
terminating resistor at one end of the Modbus segment in
question with the optional series RC terminator included
with your Modbus Monitor.
3. Time stamps at the
Monitor Event Log do
not match the time stamps
seen at PMCS Event
Logger. Clock settings differ between
PMCS host PC and Modbus
Monitor.
Daylight Savings Time in effect.
Use the setup menu to set the Monitor’s system clock to
the correct time.
4. I’ve forgotten the
password for my
Monitor! Misplaced password Contact a GE Resolution Engineer at 1-888-GE-RESOLV
for assistance.