Serious Issue in Modbus Binding


i am using Modbus binding on Raspberry PI4 (Openhabian 3.0.2) with RS-485 to USB convertor , it work great with no issue but i have noticed sudden crash for Openhab quite often now which means openhab stop working or responding at all and USB stop communication to modbus salve devices .

finding :

  1. when i have error in log for modbus RS-485 communication (via USB convertor) the crash happen and when i have more error the crash happen faster.
  2. when crash happen openhab stop responding and logs are freezes while i still can access SSH and reboot Raspberry PI.

any help please


UID: modbus:serial:156451a229
label: 2_Serial Slave Micro
thingTypeUID: modbus:serial
  baud: 9600
  timeBetweenTransactionsMillis: 35
  connectMaxTries: 1
  stopBits: "1.0"
  parity: none
  receiveTimeoutMillis: 1500
  dataBits: 8
  echo: false
  encoding: rtu
  flowControlIn: none
  port: /dev/ttyUSB0
  flowControlOut: none
  connectTimeoutMillis: 10000
  id: 2
  enableDiscovery: false
UID: modbus:poller:156451a229:50f7d7d314
label: 2_ DO Poll
thingTypeUID: modbus:poller
  start: 220
  length: 1
  refresh: 50
  maxTries: 3
  cacheMillis: 50
  type: coil
bridgeUID: modbus:serial:156451a229
UID: modbus:data:50f7d7d314:ce5fe50177
label: 2_DO 3
thingTypeUID: modbus:data
  readTransform: default
  writeType: coil
  writeTransform: default
  updateUnchangedValuesEveryMillis: 1000
  writeValueType: bit
  writeMultipleEvenWithSingleRegisterOrCoil: false
  writeMaxTries: 3
  writeStart: "220"
bridgeUID: modbus:poller:156451a229:50f7d7d314

Your screenshot doesn’t show any crash. It does show a WARN from the binding, that it had an error and is going to retry the transfer. This would be pretty routine stuff in itself for Modbus.

This sounds like problems looked at in this long thread, essentially if you have a “routine” serial comms error, the recovery may go wrong.

Some work has been done, so you might want to move up to Milestone or Snapshot version to get that, or wait for 3.1 release due soon.

yes correct my screenshot does not till any thing about the crash and im not sure where to find the right logs because that all what i found and i’m not linux user to go deep in linux side

looks like the thread is about the same , thanks for sharing this will be helpful