Are there Modbus registers that I can write to to show AC Loads and Inverter / Charger status?

Q&A and troubleshooting EVCS
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I have a Victron EVCS that has its screen as shown above. It’s in a shed and I can’t run cabling down to my main switchboard due to conduit / other issues. I can communicate with the EVCS via Modbus TCP and I intend to control the inverter in manual mode by manipulating the start / stop charging and the charging current / max current registers from a PLC. I have tested that I can manipulate those registers and see the changes immediately on the web interface to the EVCS. I am wondering if it is possible to manipulate other registers, perhaps not shown on the “EVCS-Modbus-TCP-register-list-v3.6”, to allow display of the other data displays (currently blank on the screenshot) and possibly even have the Victron regulate its own charge based on those values. Not a biggie if I can’t, it would just look cleaner. I do not have a GX device or any other relevant Victron equipment installed. I’m hoping given that the GX device talks Modbus TCP so I believe, that if it provides the data to the EVCS then I could do similar just by knowing the registers.

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Update, I have used a Raspberry Pi 4 being a GX device, combined with Wireshark and the “CCGX-Modbus-TCP-register-list-3.60” to work out where the GX device registers are containing the critical information that I need to relay to my EVCS. Most of the parameters we’re interested in are com.victronenergy.system on address 800-883. I will configure my SCADA system (Ignition Maker Edition) to act as a Modbus gateway to provide readings from my Fronius inverter and smart meter as if it were a GX device (and put dummy / manual commands where necessary) so that I can integrate as required.

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For reference I had an old PLC that talks Modbus TCP and has practically no code in it (for those interested, it’s an old Koyo DL260) - it literally has a couple of relays to drive my shed doors, plus a couple of optical sensors to detect doors open.

The registers I used to simulate the GX Device and make the above work were as follows (See CCGX-Modbus-TCP-Register-List-3.60):

  • 808 - PV - AC-coupled on output L1 - sent the solar output from my inverter
  • 817 - AC Consumption L1 - sent the property consumption from my smart meter at the grid feed in point
  • 820 - Grid L1 - sent the difference between solar and consumption which is equivalent to import and export - negative means exporting to grid
  • 843 - Battery SoC - sent 100 (%) as I don’t have a battery.

With those 4 values made available as Modbus TCP registers in the PLC, and with the EVCS pointed at my PLC under the “GX Device” settings, the system now charges with excess solar.

I tweaked the settings for current ramp up and down using Modbus registers writing directly from a Modbus TCP client pointed at the EVCS (in my case Ignition Maker Edition). Those registers are detailed in EVCS-Modbus-TCP-register-list-v3.6

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