question

essuser avatar image
essuser asked

Multipluss II - Is "External Control" ESS Mode 2 or 3?

Hi

There are 2 Modes which allows to controll the Multiplus II with an own Script.

ESS Mode 2 and 3

But how to enable them?

The answer I found to this was set the ESS mode to external control.

If there are 2 Modes why there is only one Setting? If I set ESS Mode to external controll is this enabling Mode 2 or mode 3?

The victrom ESS description is not answering that.

(https://www.victronenergy.com/live/ess:ess_mode_2_and_3)

Thanks in advance



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1 Answer
wkirby avatar image
wkirby answered ·

Mode 1 is default and no control points are used at all. The control loop is automatic.
Mode 2 is the same as mode 1, but Mode 2 is "enabled" by writing control points to the system by Modbus or MQTT. You don't need to set or select mode 2, you simply write control points and then the system will no longer be mode 1 and will now be mode 2. The control loop is still automatic, but you have the ability to adjust certain parameters of the control loop.

As you already know, Mode 3 must be selected and then you are on you own. The control loop becomes externally controlled and you MUST provide the parameters that you require for the control loop.

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essuser avatar image essuser commented ·

Thanks for the quick answer !

That also fits to the test I already did. I modified the Grid Setpoint via Modbus TCP (Register 2700) and it worked as expected.

I just stopped because:

  1. I was not clear if Mode2 need to be enabled somewhere else (which is now perfectly answered)

    2. It’s not clear to me which type of register I write to. If it’s a Flash or Ram ???
    If it’s written to the Flash a script which updates the value regularly will possibly destroy the register within days as a flash usually has about 100.000 write cycles only.

    My main solar inverter is from SMA solar and they also have a Modbus interface. They clearly indicate in their list which registers are flash and shall not be written regularly and which once are RAM registers which permanently can be updated.

    Such a labeling I miss in the Victron Modbus register List.

    I guess at least registers marked as “com.victronenergy.settings” should be RAM registers but if I “guess wrong” I destroy my Multiplus II if I update the value every few seconds.

Is there somewhere a definition about Register types?

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karl4 avatar image karl4 essuser commented ·

I have same question,Flash or Ram registers?

I would like update them at least once per second when implementing mode 3

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shaneyake avatar image shaneyake karl4 commented ·

I believe everything that is VE.BUS is RAM. These valves all get reset if you reboot inverter.
The inverter flash is only modified when using VE.Config.

Registers 37-41 are your friend. I have been updating once a second for years, no problems so far. Victron ESS, changes these exact registers for there own ESS control, just via dbus rather than ModBus.

com.victronenergy.settings registers live on the GX and will survive a reboot so those are most likely flash. I would not update at any high frequency. Most are disabled in Mode 3 anyways.

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