H3/AC3 and DRM0

[kozobera]

Hi all,

can you clarify to me what the DRM0 function (described in the user manual https://www.fox-ess.com/wp-content/uplo ... Manual.pdf) does exactly? For what is it used?

Thank you.

David

[ljalves]

I was wondering the same thing (different inverter, S series G2) and googling around I think it's more or less this:
(please anyone correct any mistake)

Some countries (like Australia) somehow control this modes by powerline comms and they call it DRM.
DRM = Demand Response Mode
DRM0 = DRM mode 0 (there are more modes).

Quoting some doc talking about inverters:
"[...] One of these requirements is demand response mode for zero export (DRM 0), which reduces export to grid to zero upon
command from the utility".


Putting it all together, I believe that if you enable DRM0 in the settings (and you have a CT clamp/meter connected) then when this input pin is shorted to GND the inverter will not export any power.

[ljalves]

Also found:

[BikerSam86]

I was wondering the same thing (different inverter, S series G2) and googling around I think it's more or less this:
(please anyone correct any mistake)

Some countries (like Australia) somehow control this modes by powerline comms and they call it DRM.
DRM = Demand Response Mode
DRM0 = DRM mode 0 (there are more modes).

Quoting some doc talking about inverters:
"[...] One of these requirements is demand response mode for zero export (DRM 0), which reduces export to grid to zero upon
command from the utility".


Putting it all together, I believe that if you enable DRM0 in the settings (and you have a CT clamp/meter connected) then when this input pin is shorted to GND the inverter will not export any power.

PIN           │3         │4
Definition │DRM0 │+3.3V

Model   │Socket asserted by shorting pins     │ Function
DRM0   │3 4                                                       │Operate the disconnection device.

Just to chime in, this excerpt from the manual for my H1/AC1 seems to match this with the exception of the DRM0 pin [3] being shorted with the +3.3V pin [4] (Pulled High) to trigger the export disconnect.

DRM0 Also needs enabling in my inverters menu with this:
Settings > Feature > Parm > DRM0 > Enable/Disable

I'm looking at it for Export control with my energy supply for dynamic electricity tariff pricing.
Shame I've not found a way to set the inverter charge timings outside of the website/app/API.
I would love a net-less, head-less way to manage the inverter with HomeAssistant short of connecting a microcontroller to the inverters input buttons.

I hope this is of some use to someone.

Sam