External CT - Modbus Link
With an external CT using Modbus comms, there is a problem and the link is broken (for what ever reason), the Inverter throws a W04 fault and this will not clear without a full shutdown and restart of the inverter. A restart always fixes the issue.
This is a pain and is quite limiting.
I would suggest that there is a firmware upgrade that has some form of watchdog and then a reinitialisation of Modbus comms when a W04 fault and External CT is in use. This would then prevent a fall restart.
For info, I have tried with no positive result
1. To restart the slave of the Modbus
2. To leave for a period of time
3. Improve the RS485 link - does help
4. Change the settings from Internal to External CT
It seems to be that the solution is probably a firmware update.
I am not familiar with the ESMB1 Modbus Wifi Bridge, but looking up the specs they should do the job.
I had the same issue with a 3 phase version of the Eastron meter. I had to get Sunsynk to send me an official version (that they provide) and this resolved my W04 warnings.
Which SDM120 meter do you have?
What is the CT ratio ?
My personal system use a SDM120CT-MV with a 120A/40mA CT and is also connected using a Solax Wireless bridge and it works well. The only time I get a W04 warning is when I power off the wireless bridge.