Thank you for all your suggestions. It appears we have found a solution! It involved rewiring the system as follows.
Victron prescribes the following when using a Carlo Gavazzi EM530/EM540 energy meter, in combination with the RS485 to USB interface and a CAT5 extension cable:
| RS485 to USB | RS485 Signal | EM540 terminal number |
|---|---|---|
| Orange | Data+ | 8 |
| Yellow | Data- | 9 |
| Black | GND | 10 |
where Data+/- form a twisted pair.
My solution was as follows.
- I used a CAT6 S/FTP extension cable
- connect terminal 8 and 9 of the energy meter to the wires of a twisted pair of the exension cable as prescribed
- DON’T connect terminal 10 of the energy meter
- at the other end of the extension cable, connect orange and yellow of the RS485 interface to the used wires of the exention cable as prescribed
- connect the black wire of the RS485 interface to the shielding of the extension cable
Since connecting it like this a week ago, the signal has not been interrupted and the system has been working flawlessly!