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ben avatar image
ben asked

Generator start/stop resync after manual override?

I have a Venus GX configured with a generator start/stop. The Venus correctly auto-starts and -stops the generator based on whichever conditions are set up.

Sometimes, however, I manually shut down the generator using a separate switch. Venus has no (automatic) way to know that I have done this.

At that point, no matter what settings I try to change on Venus, any change results in the Venus triggering the generator again, because it always tries to "stop" it.

Is there a way to tell the Venus to "forget" the generator state short of resetting the computer?

Generator
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Anil Ghatikar avatar image Anil Ghatikar commented ·

you can try to use the generator on/off digital input . although I am not sure if it is synced(used) with generator start-stop logic

https://www.victronenergy.com/live/venus-gx:start

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Kevin Windrem avatar image Kevin Windrem commented ·

I'm not sure how you currently have this configured since the generator start/stop relay normally closes to start the generator and keep it running and opens to stop the generator.

If your generator has a close to start/close to stop input then it will be difficult to integrate the generator with any automation system.

I suspect you already have some logic somewhere that takes the run/stop relay out of Venus and converts BOTH edges to a start/stop pulse to the generator. If that's the only input to the generator then the place to apply a fix is in that logic. You can take a signal from the generator and only generate a pulse when the Venus relay closes IF the generator isn't already running and only create a pulse when the relay opens if the generator IS running.

You might want to look at the generator for an alternate input: either a run/stop input or separate start and stop pulse inputs.

Also try the generator run/stop input to Venus as Anil suggests.

What generator are you using (make and model)?

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ben avatar image ben ♦ Kevin Windrem commented ·

The problem with absorbing/correcting the logic downstream of the Venus device is that then Venus does not always know, nor report or display, the status of the generator when it is started externally.

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ben avatar image ben ♦ Kevin Windrem commented ·

I can confirm that the ECM on my generator does not have an alternate start input that uses the matching logic. I am using a (stateful) converter in line to convert the edges to pulses.

The generator is a build-up by Powertech, but they implement different ECMs all the time, so there is no single model I can reference, unfortunately.

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bowpay avatar image bowpay ben ♦ commented ·

I am using 2 delayed relays to stop and start the diesel generator as per the Victron suggestion. I am also using the I/O digital input. Why can't the I/O port handle the status for all generator status calls? This seems like an easy fix or maybe I'm missing something?

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3 Answers
jperez (Victron Energy Staff) avatar image
jperez (Victron Energy Staff) answered ·

The Generator start/stop function will keep the relay closed as long as the one of the conditions is met.

As you said, if you manually stop the generator the Venus GX doesn't know it.

You have two options to reset the state on the Venus GX, one is switch off the auto start functionality from the generator start/stop menu or set the relay function to Alarm relay on the relay settings menu.

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ben avatar image ben ♦ commented ·

When I switch off the auto start button, it sends another "stop" signal to the generator. This actually STARTS my generator again, since stop and start are the same signal for my generator.

What I want is to reset the internal state of the Venus GX.

Any ideas?

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jperez (Victron Energy Staff) avatar image
jperez (Victron Energy Staff) answered ·

The generator start/stop doesn't send a signal it just drives the Venus GX relay and the relay and the generator start/stop state must be always on sync and currently there is no way to change the state without acting on the relay.

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ben avatar image ben ♦ commented ·

That's what I was afraid of, thanks.

I would like to make this a feature request: we need an option in the Venus generator menu to "reset state" or something. Some way to reset the logic when the generator is no longer in sync with the Venus. It is a trivial programming exercise, but otherwise there is no way to get a generator and the computer back aligned with each other, except cycling the generator back on (and then immediately off, not good for the engine!) or rebooting the Venus (unacceptable in a production environment with it managing many other devices).


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ben avatar image ben ♦ commented ·

Should I make a separate FR topic?

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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ ben ♦ commented ·

Hey Ben, isn’t it wiser to look into changing that generator wiring to a more suitable setup for a system like this?


Without the possibility of getting out of sync?


Ie either a separate start and stop pulse, or an input that will start and keep it running when closed, and stops when contact is open.

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ben avatar image ben ♦ mvader (Victron Energy) ♦♦ commented ·

@mvader (Victron Energy Staff) definitely reasonable to think of doing it elsewhere in hardware, but not trivial since the ECU on the generator is completely integrated. An external solution would have to be designed, and it would need not only to interpret pulses but also calculate the state of the generator, presumably by measuring the AC output. Which, by the way, Venus can already see via the inverter. :-)

[cont'd]

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ben avatar image ben ♦ ben ♦ commented ·

[cont'd]

Some way to tell the generator management logic to reset itself would be a simple and foolproof option, whether or not we also get a cleaner ECU implementation downstream.

(I say simple, not knowing how much work would really be involved!)

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ben avatar image ben ♦ ben ♦ commented ·

p.s. If the dbus values exposed on

com.victronenergy.generator.startstop

are an option here, I could see this being easy for someone to add without needing a new feature from Victron.

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bowpay avatar image
bowpay answered ·

Hi Ben, Thanks for the helper earlier! Found your post wanting the same thing. The answer from Victron is UNACCEPTABLE! This is BASIC functionality of MOST RV systems. If there is no way to know when the generator is running because it was manually turned on then the whole thing is out of sync. I am willing to pay a developer to fix this for me. I started looking into the classes but confused as the context of the menus. Will be referencing this post in another post.

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ben avatar image ben ♦ commented ·

Yeah, I wasn't sure if your scenario you posted was the same as mine, so I was hesitant to comment in more detail.

I actually think it would be possible to write some code that would run on Venus and update/overwrite the generator status by watching the incoming power on the appropriate AC input.

Done well, it would probably catch the desync most of the time, if not all of it, and mostly eliminate the issue. I have not looked into it enough to know for sure if it is doable out of the box, though. The genstart variables need to be writeable for it to be possible.

It's also possible that the genstart code is already open source, in which case one could envision simply going in and augmenting the base logic. I can't remember off hand if that's one of the released drivers or not.

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