Unable to connect VM-3P75CT

DIY
, ,
1

I recently purchased a VM-3P75CT (brand new, locally in SA from http://createenergy.co.za) but I am having trouble getting my cerbo gx to see it. I did a fair bit of trouble shooting with the docs and on my own with no luck.

What works:

  • Powering on the device the green LED comes on and stays green
  • Initiating a reboot the green LED returns to green as expected
  • Initiating the exact factory reset (many times), the green LED goes through the correct sequence as per the manual (and returns to solid green)
  • Connecting an ethernet cable and monitoring the traffic on my router I can see it is offered and accepts an IP from my DHCP server (and responds to pings)
  • When connected via ethernet, if I do a port scan I can see one tcp port open 19200 and nothing else (more on that at the bottom)

What does not work:

  • When connecting via ethernet, my cerbo gx does not find the device (initiating auto scan)
  • When connecting via ethernet, my cerbo gx does not do anything if i manually configure the ip (as leased by dhcp) and some port combinations.
  • When connecting via ethernet, I expected to maybe find port 502 open on the device but it does not appear to be.
  • When I daisy via VE-CAN (with terminating caps) either on the mppt or on the other open VE-CAN port on the cerbo-gx it is not picked up/detected
  • Any of the above with the victron connect app - does not see it either

Other info:

When I look via wireshark what it declares during the DHCP query sequence i see some info, not sure if any of it helps in terms of versions etc (serial masked):
Victron-VM-3P75CT-HQ24096****.local: type TXT, class IN, cache flush
Name: Victron-VM-3P75CT-HQ24096****.local
…
TXT Length: 9
TXT: victron=1
TXT Length: 11
TXT: prodid=A1B1
TXT Length: 18
TXT: serial=HQ24096****
TXT Length: 13
TXT: appver=1.4.ff
TXT Length: 14
TXT: bootver=1.2.ff
TXT Length: 8
TXT: mode=app
TXT Length: 11
TXT: updatable=1
So from that (and the LED) i would say it is for sure in full app mode

Port 19200:
I did a bit of digging around port 19200 and it looks like when i curl to it (force http 0.9!) then I get back a busy stream of what looks like MODBUS ASCII messages (:[addr][func][data][crc][br]) if i am not mistaken (Modbus - Wikipedia - ASCII section). I have been meaning to write some python to decode some of it but it I dont have time at the moment and need to get this working)

Here is an example:
:4AAAAFD
:2AAAAFF
:4AAAAFD
:4AAAAFD
:A50220054582D
:A552200BD1DFA
:A5A2200BD1DF5
:A0922004600DA
:A50220052582F
:A552200BB1DFC
:A5A2200BC1DF6
:A0922004700D9
:A502200505831
:A552200BC1DFB
:A5A2200BC1DF6
:A0922004800D8
:A34220000000000F5
…

Based on what the device is doing (LED and also the output from the port above) it appears to be working…? I just cant get my cerbo gx to see it and I suspect I am just doing something daft.

Thanks,
Riaan

2

Did you put the latest firmware (1.06) on it with victron connect?

3

I am using the victron connect mobile app - it looks like it needs to be able to detected it before that is possible. Is there another way?

4

I don’t know. Did you use normal LAN cables with VE Can? I have 2 VM-3P75CT and they worked right out of the box.

5

Yes, I was expecting the same from what i read on reviews, etc before buying it. I did use normal lan cables yes on ve-can - that an issue?

Ah, you mean via the pc app - I am on linux so that is probably going to be my next problem :smiley:

6

I see there is a app for linux - will have to give that a try. Was just hoping it would not have to be so much effort

7

No I meant the mobile app.
Normal LAN cables is not an issue

8

Ok, great, but is it possible to update the firmware if the device can not be detected?

9

I don’t now, I don’t think so because it’s not visible in the VRM.

10

When you open victron connect on your mobile, VRM, you choose your installation. Did you then choose devices?

Is the Cerbo/GX device on firmware 2.90 or higher?

11

It was from what I recall I think, but I have just now run an update to v3.42 - will try with that quickly

12

Ok, this is properly embarrassing. I should have updated my cerbo gx - now it can see it.

Thank you Ton

13

Just to confirm as well, VE Can also works now as expected, instantly picked it up on the cerbo gx

14

:+1:, I think that’s the preferred connection.

1 Like
15

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