[SOLVED] Modbus connection on USB

[Gianluca_C]

Please!.
I did it seeing

Raspberry Pi - Make serial USB ports persistent via symlinks

Usually, USB sticks attached to Raspberry Pi will get assigned ports in an increasing manner such as /dev/ttyACM0, /dev/ttyACM1, etc. This may become a problem whenever you reattach your USB devices to a different port, you add new devices, or you simply reboot your RPi. The reason is that one specified device may be recognized earlier than another while booting the RPi. You could make these ports permanent via so called symlinks and give them more telling names in contrast to ttyACM0. SSH i…

so it appens very a strange thing…
Starting work well for more minutes then when i try to change the refresh time of polling it stops work and doesn’t start anymore.

this is the error message.

==> /var/log/openhab2/openhab.log <==
2019-11-15 16:15:34.433 [ERROR] [et.wimpi.modbus.net.SerialConnection] - Could not get port identifier, maybe insufficient permissions. gnu.io.NoSuchPortException: null

==> /var/log/openhab2/events.log <==
2019-11-15 16:15:34.435 [hingStatusInfoChangedEvent] - 'modbus:data:rtu1:bloccoenergia:energia1' changed from OFFLINE (BRIDGE_OFFLINE) to ONLINE

==> /var/log/openhab2/openhab.log <==
2019-11-15 16:15:34.436 [ERROR] [ing.ModbusSlaveConnectionFactoryImpl] - connect try 1/1 error: Could not get port identifier, maybe insufficient permissions. null. Connection SerialConnection@1cfd9e4[portName=/dev/ttyUSBGed,port=<null>]. Endpoint ModbusSerialSlaveEndpoint@d512e0[portName=/dev/ttyUSBGed]

2019-11-15 16:15:34.437 [ERROR] [ing.ModbusSlaveConnectionFactoryImpl] - re-connect reached max tries 1, throwing last error: Could not get port identifier, maybe insufficient permissions. null. Connection SerialConnection@1cfd9e4[portName=/dev/ttyUSBGed,port=<null>]. Endpoint ModbusSerialSlaveEndpoint@d512e0[portName=/dev/ttyUSBGed]

2019-11-15 16:15:34.438 [ERROR] [ing.ModbusSlaveConnectionFactoryImpl] - Error connecting connection SerialConnection@1cfd9e4[portName=/dev/ttyUSBGed,port=<null>] for endpoint ModbusSerialSlaveEndpoint@d512e0[portName=/dev/ttyUSBGed]: Could not get port identifier, maybe insufficient permissions. null

2019-11-15 16:15:34.440 [WARN ] [rt.modbus.internal.ModbusManagerImpl] - Could not connect to endpoint ModbusSerialSlaveEndpoint@d512e0[portName=/dev/ttyUSBGed] -- aborting request ModbusPollerThingHandlerImpl.ModbusPollerReadRequest@165451a[slaveId=1,functionCode=READ_MULTIPLE_REGISTERS,start=4131,length=4,maxTries=3] [operation ID f0b95356-aa48-47fd-a50f-0d64cef82809]

2019-11-15 16:15:34.441 [ERROR] [ernal.handler.ModbusDataThingHandler] - Thing modbus:data:rtu1:bloccoenergia:energia1 'Modbus data' had ModbusConnectionException error on read: ModbusConnectionException(Error connecting to endpoint=ModbusSerialSlaveEndpoint@d512e0[portName=/dev/ttyUSBGed])

==> /var/log/openhab2/events.log <==
2019-11-15 16:15:34.447 [hingStatusInfoChangedEvent] - 'modbus:data:rtu1:bloccoenergia:energia1' changed from ONLINE to OFFLINE (COMMUNICATION_ERROR)

2019-11-15 16:15:34.451 [hingStatusInfoChangedEvent] - 'modbus:poller:rtu1:bloccoenergia' changed from ONLINE to OFFLINE (COMMUNICATION_ERROR): Error with read: org.openhab.io.transport.modbus.ModbusConnectionException: Error connecting to endpoint ModbusSerialSlaveEndpoint@d512e0[portName=/dev/ttyUSBGed]

2019-11-15 16:15:34.455 [hingStatusInfoChangedEvent] - 'modbus:data:rtu1:bloccoenergia:energia1' changed from OFFLINE (COMMUNICATION_ERROR) to ONLINE