GE Industrial Solutions POWER LEADER ModBus Monitor - Manual (Page 44)

POWER LEADER Modbus Monitor
Chapter 6 – Troubleshooting Guide
38
Symptom Possible Cause Corrective Action
5. No communication to one
or more Modbus devices;
some devices OK. The device or a repeater is not
powered.
RS-485 wiring is shorted or
improperly connected.
An RS-485 shield has been
grounded incorrectly.
Network configuration is incorrect.
The device is not addressed.
Two or more Modbus devices
have the same address.
Network not properly terminated.
Check that all devices and repeaters have control power.
If a device does not operate when control power is
present, contact the GE Resolution Center.
Locate and remove the incorrect connection.
Refer to Chapter 2 for RS-485 grounding considerations.
Recheck RS-485 network for compliance. Improper
grounding can cause communications errors.
Check that the network conforms to the rules in Chapter 2
regarding RS-485 wiring. Check any dual-port devices to
be sure that each RS-485 port is wired to a separate RS-
485 network.
Ensure that each device’s Modbus address corresponds to
the address set at the Monitor.
Check devices for duplicate address assignments. Change
the address of the affected device, attempt to
communicate with the original address to see if another
device has that address.
Check that each RS-485 segment has been properly wired
and is correctly terminated at each end.
6. Garbage data displayed
on screen or display not
updating. Device type may be incorrect. Check the device type assigned to the device at that
network address. The device type assigned at the Monitor
must match the real device at each address.
7. Display doesn’t update
when Monitor is in slave
mode and another
Monitor is master. Multiple devices may have the
same Modbus address. Make sure that each device has a unique Modbus address.
8. Monitor malfunctions
while in slave mode. Modbus addresses have been
changed for one or more devices
on the segment without the
Monitor’s configuration being
updated to match. When changing the Modbus address of a device or
changing any of the network configuration parameters,
put the Monitor into Setup mode. Make any local changes
at devices, change the Monitor configuration with the
Configuration Tool, and download the new configuration
to the Monitor before returning the Monitor to normal
operation.
9. PMCS Troubleshooting:
No communications with
Event Logger client. Event Logger not running or
program has hung.
PMCS DDE Server not
functioning.
Check to make sure that the Event Logger client software
is running correctly.
Check to make sure that the PMCS DDE Server is
running correctly.
10. In Slave mode under
PMCS, some or all
displayed values not
updating; fields show
***. Modbus Monitor Proxy not
running. Check to make sure that the Modbus Monitor Proxy is
running.