Multiple ET112 in parallel on single USB

Q&A and troubleshooting
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1

Hello Community,
I have 4x ET112 Energy Meters.
I changed the ID of 4 of the units to 2,3,4,5. I am leaving 1 open for the 5th meter which is yet to arrive. The 4 all are displayed in the UCS software and not conflicting.
When I plug them in to the Cerbo GX via the same RS485 to USB adapter, nothing happens, they are not seen at all. Removing 3 and retaining one allows the communication to return to the 1 device. Plugging the other 3 in again stops the communication.
What’s the deal here? Anyone actually had this working with multiple units on one rs485 to USB adapter as stated in the manual? I tried adding terminating resistor, but it shouldn’t be required because it works flawlessly on my pc.

Here’s the section from the manual i’m refering to:

2.4. Multiple Energy Meters in one system
To connect multiple Energy Meters, wire each meter to a separate RS485 to USB interface, which are then each plugged into a separate USB socket on the GX device.
Connecting multiple meters to the same RS485 to USB interface cable is not possible.
Please note that you can connect the ET112 in parallel, but need to change the modbus address to another number using the
UCS Desktop configuration software from the supplier, which is free to download from the Carlo Gavazzi Web site.

2

Hi that is not possible, all in the manual of the et 112

Only 2 is possible at adress 1 and 2

If you need to connect more use another usb to rs485 cable and also adress them as 1 and 2

Also keep in mind to use a good quality powered usb hub

1 Like
3

Thanks for the prompt reply,
Ok so 2 per adapter, sounds fine.
Where is this documented? or is it just a trial-and-error thing?
I reset their ID’s to 1 & 2, can confirm 2 showing now.

4

The part with the adresses is not really documented, the CG energy meters are all on adress 1 by default

but its a question that is asked a lot, the 2 pieces is in the manual (the part you already posted)

5

I have 2 meters and 2 usb leads one set to address 1 the other to address 2
I have been trying to add a third meter with its own usb set to address 3,
Just saw this post set the address back to 1 and at last have 3 working meters.
Never saw anywhere about only mod bus 1&2 can be used,
Glad I saw this post before posting my own question

6

You can sort off find it in the modbus adress list, but im not shure its really documented anywhere

https://www.victronenergy.com/upload/documents/CCGX-Modbus-TCP-register-list-3.50.xlsx