Honeywell SMV800, User Manual

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Page 186 SMV800 Modbus User's Guide Revision 1.0
5. Troubleshooting
5.1 Overview
Using the Honeywell Modbus Host in the on-line mode you can check the transmitter status
by navigating into Monitoring tab, identify diagnostic messages and access troubleshooting
information so you can clear fault conditions.
Refer section 6.3 to understand alarams and its resolution
The SMV Modbus diagnostic messages fall into any one of the following general
categories:

Critical

Details of Critical Fault

Device Variables Status

Warning

Information
5.2 Communications troubleshooting
5.2.1. Device not visible on the network
The table below identifies the causes of the communication problem with the SMV800
Modbus Transmitter.
Symtom Corrective action
No communication between Honeywell SMV800
Modbus transmitter interface software and the
transmitter. 1. Check proper voltage across the power
terminal of the transmitter (9.5V
– 30 Vdc
).
2. Check Com port selected correctly.
No communication between transmitter and host 1. Check proper voltage across the power
terminal of the transmitter (9.5V
– 30
Vdc).
2. Verify the RS485 bus terminated with
120 Ohm resistor or via AC termination,
at each end of the bus.
3. Verify the RS485 bus is not terminated at
point other than at each end of the bus.
4. Check for intermittent shorts, open
circuits and multiple grounds.
5. Verify the power wiring and RS-485 bus
wiring are not interchanged.
6. Verify the RS-485 wires are connected to
correct communication terminals (A,B
and RS485 common) Verify the
grounding scheme is followed as