Connect Goodwe Inverter via RS485 Modbus RTU

[pioneersteffen]

Hi @all,

I want to connect my Goodwe Inverter to W4K/LM via Modbus RTU. Attached you can find the protocol description.
I tried to transfer the document in a Modbus config and performed a Read Test for the “Ipv1” value (pictures attached) but unfortunately it doesn’t work.

Can you please help me and give me a hint what I may making wrong? 

Many thanks for your help!

Best Regards 
Steffen

[admin]

What error do you get when doing read test?

[pioneersteffen]

Hi Admin,

many thanks for the response and sorry for my late reply.

The failure message is timeout, see picture attached.

Any ideas what I need to change?

Many thanks for your help!

Best regards 
Steffen

[Daniel]

Make sure RTU settings on the inverter are the same as in W4K, Try changing +/-

[pioneersteffen]

Hi Daniel,

I changed +/- and were successful in getting response from the inverter.

BUT now I getting a strange behavior of the W4K. It restarts every approximately every 3-4h. It is definitely related to the RS485 connection.
Any idea why? I have no resistor oder termination in the RS485 bus and just 2 wires D+/D- connected. Also just the W4K and the Goodwe inverter are on the BUS.

Many thanks for your help!

Best Regards
Steffen

[pioneersteffen]

Hi @all,

I found the solution for the issue. After I added 120 ohm resistor termination to the wiring no reset of W4K happened anymore.

Best regards
Steffen