Emerson 5400, 5300 specifications Troubleshooting No communication on RS-485 bus MA, MB

Rosemount 5300/5400 Series

Manual Supplement

00809-0500-4530, Rev AA October 2010

TROUBLESHOOTING No communication on RS-485 bus (MA, MB)

•Check that the cables are connected

•Check that PWR+ is connected to + and PWR- is connected to - on the power supply

•Make sure the 5300/5400 transmitter is supplied with 8-30 Vdc (max. rating)

•Try alternating MA/MB if you are unsure of the polarity

•If an RS-485 converter is used, make sure it is properly installed and configured

•The last 5300/5400 transmitter may need a terminating 120-Ω resistor connected between MA and MB

No 5300/5400 communication in RRM

•Using HART+, HART-

•HART modem is not properly connected

•Polling address is incorrect in RRM (default 1)

•Using MA, MB

•See No communication on RS-485 bus

•Polling address is incorrect in RRM (default 1)

•Cycle the power and wait 20 seconds before polling

No communication with Modbus RTU protocol

•See No communication on RS-485 bus

•Make sure the “Modbus Communication Protocol Configuration” is done properly

•Make sure the Modbus RTU address is unique on the bus

•Cycle the power and try to connect

•Check the RTU communication settings

No communication with Modbus ASCII protocol

•See No communication on RS-485 bus

•Make sure the “Modbus Communication Protocol Configuration” is done properly

•Make sure the Modbus ASCII address is unique on the bus

•Cycle the power, waiting 40 seconds before communication begins

•Check the RTU communication settings

No communication with Levelmaster protocol

•See No communication on RS-485 bus

•Make sure the “Modbus Communication Protocol Configuration” is done properly

•Make sure the Levelmaster address is unique on the bus

•Cycle the power, waiting 40 seconds before communication begins

•Check the RTU communication settings

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