Hello everybody. I am new to this forum and this ist my first post.
I have a victron Multiplus II with 2 Pylontech US2000C, a venus GX and an ET340 meter.
I use this setup in my house (3 phases). Two PV inverters are AC coupled. So the venus does not know exactly how much energy the PV inverters are producing, despite that the ET340 is measuring how much energy is fed into the grid.
ET340 and venus GX are connected using an USB-RS485 adapter.
Everything works fine so far, as long as I use the screw terminals on the ET340.
Using the RJ45 connector didn't work.
Once again:
ET340 (screw terminal) - USB-RS485 adapter - venus GX (or Carlo's software) worked
ET340 (RJ45) - RJ45 (screw terminal) - USB-RS485 adapter - venus GX (or Carlo's software) didn't work
I will mention this ET340 as ET340-grid from now on
I thought it is a good idea to measure the energy coming from the solar inverter seperately.
And it seemed to be the easiest way for me to buy another ET340, since I have 2 PV inverters on 2 phases. I tested the additional ET340 (ET340-PV from now on) on my workbench using the existing USB-RS485 adapter and an RJ45 plug with screw terminals. I used Carlo Gavacci's software to check the ET340-PV and to assign the Modbus address "2" to this device. Worked fine using the RJ45 connector (RJ45 plug with screw terminals and the USB-RS485 adapter).
When I say "worked" in the following sentences I always mean it worked connected to Carlo's software as well as the venus GX. When an ET340 does not work, it also means that the left green LED does not show communication.
I then connected the USB-485 cable to RJ45 plug at ET340-grid. Doesn't work, no connection possible.
Using the screw terminals at ET340-grid worked.
Connecting the two ET340s with a RJ45 patch cable (8 wires) and connecting this using the RJ45 Adapter with screw terminals und the attached USB-RS485 Adapter only shows the ET340-PV.
In the same setup, when I remove the patch cable and connect the two ET340s with a twisted pair cable using the screw terminals at the ET340s on both sides, while feeding the modbus from the USB-RS485 Adapter through the RJ45 plug with screw terminals, it worked.
In short: ET340-Grid (screw terminals) - twisted pair cable - ET340-PV (screw terminals) - ET340-PV (RJ45) - RJ45 plug with screw terminals - USB-485 cable - venus GX
So it seems to me, that die ET340-grid does not have a connection between its screw terminals and its RJ45 sockets. I checked, that the 2 RJ45 sockets are connected.
Does anyone have any idea what is wrong?
Is ET340-grid simply defective?
Kind regards
Klaus
