RS485 Modbus TCP bridge MBR Driver receive error 9

[naseweiss99]

Hello,
I am trying to connect a Sun2000 10kw inverter to connect via Tasmota 14.5 .0 on an ESP32 to home assistant.

First of all I have to mention, when connectiong with the same setup to FHEM and EVCC it is working perfectly - connecting HA via the internal modbus Interface is working, too. And connecting with a Waveshare modbus TCP RS485 adapter is working, too.

When using the Tasmota Modbus TCP interface (working e.g. for FHEM) I get when trying to connect to Home Assistant this messages:

12:39:35.398 TCP: MBS: MBRTCP Got connection from 192.168.178.147
12:39:39.354 MBS: MBRTCP to Modbus TransactionId:1, deviceAddress:1, functionCode:3, startAddress:30000, count:65, recvCount:65, recvBytes:130
12:39:39.355 MBS: Serial Send: @01 f:03 r:7530 c:65 &:00000000
12:39:39.357 MBS: Serial Send: 01 03 75 30 00 41 9F F9
12:39:39.548 MBS: Serial Received: 01 03 82 53 55 4E 32 30 30 30 2D 31 30 4B 54 4C 2D 4D 31 00 00 00 00 30 31 30 37 34 33 31 31 2D 30 42 54 32 32 34 30 36 31 38 32 38 32 00 00 00 00 00 00 00 00 30 31 30 37 34 33 31 31 2D 30 30 32 00 00 00 00 00 00 00 00 56 31 30 30 52 30 30 31 2D 30 32 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 56 31 30 30 52 30 30 31 43 30 30 53 50 43 31 36 37 00 00 00 00 00 00 00 00 00 00 00 00 00
12:39:39.553 MBS: MBRTCP from Modbus TransactionId:1, deviceAddress:1, writing:9 bytes to client (error:9)
12:39:39.555 MBS: MBR Driver receive error 9

I tried to increase the timeout in TasmotaModbus.cpp - no effect.
Modbusdebug is enabled as seen above.

I believe the issue must be in Tasmota, as e.g. a Waveshare Modbus to RS485 is working. Could it be that Tasmota is overwhelmed by 130 received bytes ? :-)

Has anybody experienced a similar problem ? What to di to dig deaper into it? I captured the TCP traffic in wireshark, but I am not finding the point there.

Setup is Huawei Sun 2000 10 ktl m1 connected via RS485 Interface to GPIO 1 & 3 - this part is working in principle - as e.g. FHEM get the data.

cheerio

[naseweiss99]

short update - if i remove the crc check in tasmotamodbus.cpp, Tasmota at least tries to write to the client. However, it is not correct and Home Assistant does not recognize it.

Is the "Modbus sent to TCP routine" starting to early ? Before the receive is through ?
My vage idea is that the 130 bytes are too much ?

17:21:42.267 MBS: Serial Send: @01 f:03 r:7530 c:65 &:00000000
17:21:42.269 MBS: Serial Send: 01 03 75 30 00 41 9F F9
17:21:42.446 MBS: Serial Received: 01 03 82 53 55 4E 32 30 30 30 2D 31 30 4B 54 4C 2D 4D 31 00 00 00 00 30 31 30 37 34 33 31 31 2D 30 42 54 32 32 34 30 36 31 38 32 38 32 00 00 00 00 00 00 00 00 30 31 30 37 34 33 31 31 2D 30 30 32 00 00 00 00 00 00 00 00 56 31 30 30 52 30 30 31 2D 30 32 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 56 31 30 30 52 30 30 31 43 30 30 53 50 43 31 36 37 00 00 00 00 00 00 00 00 00 00 00 00 00
17:21:42.450 MBS: MBRTCP from Modbus TransactionId:1, deviceAddress:1, writing:137 bytes to client (error:0)