H1 5.0 E G2 WL. Can't get the RS485 to talk to me

[penguin]

I have a Waveshare adapter powered by PoE and I was just getting timeouts. I have switched to a Waveshare USB device and get the same.

I have connected pins 3 and 4 to B and A and pin 16 (COM) to GND.

Polarity correct
Baud: 9600, 8N1
Slave: 247

I'm testing with mbpoll

mbpoll -m rtu -p none -b 9600 -a 247 -r 1 -c 1 /dev/ttyACM0

I've been trying this for days and rewired a couple of times but I don't seem to be getting anywhere.

Can anyone suggest where I might be going wrong?

[MaterialBarracuda48]

Do you have a picture of the rear of the plug?
I use the USB waveshare device, and only wired up the A & B pins to it.

[penguin]

I'll get one later but on the top row I have them centre top and the one to the right of that which equates to mirror on the front. If that makes sense


- - B A -

As the top row. And I have it the same way up as the manual with the slightly offset row at the top

[MaterialBarracuda48]

I'll get one later but on the top row I have them centre top and the one to the right of that which equates to mirror on the front. If that makes sense


- - B A -

As the top row

That seems right to my head, as seen from behind (the direction you add the wires in)
1 being top left, and 5 being top right

1 2 3 4 5
- - B A -

[Dave Foster]

As you are using a waveshare device that is a TCP to RS485 and should be configured as TCP to modbus protocol and the correct baud rate (9600,N,8,1), I would have expected that your modpoll would be using -m tcp (not rtu)

Also not seeing a register address to poll, for example this is the command I use on modpoll to get the model name from the inverter

Modpoll -m tcp -p 502 -a 247 -t 4 -0 -1 -c 16 -r 30000 192.168.x.x (the waveshare IP address)

[penguin]

I started with the TCP device and then bought the USB device to rule out device issues. I'll try addressing the register specifically which is something I haven't done

[penguin]

I noticed something I'd got wrong. I had -p for parity instead of -P. I'm now getting a different error, I'm not sure if this is positive or not. I tried register 30000 with the same result.

Code: Select all

mbpoll -m rtu -P none -b 9600 -a 247  -r 30000 -c 1 -v /dev/ttyACM0
debug enabled
Set device=/dev/ttyACM0
mbpoll 1.0-0 - ModBus(R) Master Simulator
Copyright (c) 2015-2023 Pascal JEAN, https://github.com/epsilonrt/mbpoll
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions; type 'mbpoll -w' for details.

Opening /dev/ttyACM0 at 9600 bauds (N, 8, 1)
Set response timeout to 1 sec, 0 us
Protocol configuration: ModBus RTU
Slave configuration...: address = [247]
                        start reference = 30000, count = 1
Communication.........: /dev/ttyACM0,       9600-8N1 
                        t/o 1.00 s, poll rate 1000 ms
Data type.............: 16-bit register, output (holding) register table

-- Polling slave 247... Ctrl-C to stop)
[F7][03][75][2F][00][01][BB][59]
Waiting for a confirmation...
<F7><83><02><20><C3>
ERROR Illegal data address
Read output (holding) register failed: Illegal data address

[penguin]

One step further.

It works with the following command

Code: Select all

mbpoll -m rtu -P none -b 9600 -a 247  -r 30001 -c 10 -v /dev/ttyACM0

I switched back to the PoE device and while it did not initially work I had to change a setting. In Multi Host Settings I had to change the Protocol from None to Modbus TCP to RTU (this was probably my initial problem.

I now have it working with Home Assistant and I can look forward to data coming in and creating useful dashboards and automations.

I appreciate the input and in particular seeing your command made me question my invalid -p flag and showing the 30000 register led me to the 30001 that I needed.