question

Bruce A. avatar image

Setting up assistants in VE Configure

Hi,

I have installed a grid-connected PV system (but not feeding back in to the grid), with battery storage and ESS, for a mix of back-up and self-consumption.

I am using multiple instances of the Programmable Relay Assistant to control water heating via the MultiPlus' secondary programmable relay K1, by:

  • turning it on when insolation rises to a certain level (measured via a small PV panel's output current feeding a Schmidt trigger, which in turn drives a MultiPlus Aux input) AND AC load below a certain level AND SOC above a certain level, and
  • turning it off when any one of the three parameters reverses to a lower / higher value (i.e. with hysteresis).

One particular question is about AND / OR logic - it appears to me that:

  1. when more than one condition is set in the one assistant, then it uses AND logic, and
  2. to implement OR logic, it is necessary to use multiple instances, each with one condition.

Can anyone confirm from experience or product info', that these are correct?


I understand that the order the Assistants are listed in, in VE Configure, affects how they operate, and that those lower in the list 'override' those higher in the list. I found that my system works approximately as I want when the 'switch on' Assistant is at the top of the list. If I move it to the bottom of the list however, then the K1 relay appears to remain on permanently, irrespective of inputs, and I don't know why that should be.

I'd be grateful for any more specific / exact information about how the ordering of the Assistants functions.


When I tested control using either one of the Aux 1 input or AC load (one at a time only), they behaved perfectly, including with the delay times. However, when I combined the two in one 'turn-on' Assistant, it then appeared to ignore the delay times, and switch on instantly when both conditions were met. Any ideas about what might have caused that?


Finally, with all three inputs combined in one 'turn-on' assistant, with 'AC load lower than 1250W', I had it switching on when AC load was still around 2500W, so either it is not actually AND-ing the inputs, or the parameter is not working correctly.

Does anyone have information about exactly what the 'AC load' parameter reads?


Thanks in advance!

MultiPlus Quattro Inverter ChargerVEConfigure 3
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Just an update on the situation.

I discussed it with another installer in the area, who has used Assistants for some moderately complex tasks. We had both found that:

  • if we use more than one criterion in the programmable relay assistant, it ignores any delays that we set, and instead responds immediately when the criteria are met, and
  • when using more than one criterion in one or more assistants, they appear to behave erratically, and not according to the settings.

As far as I can tell so far, when using multiple instances of Programmable Relay, with only one criterion in each instance, they do work as one would expect, and according to the settings.

I would be interested to know what Victron knows about this.

It would be very convenient if any -AND- / -OR- statements could be made, but to be fair: I've always gotten things to work albeit with some wiring between relays and inputs.

Hi @bruce.notapple@gmail.com

I think i'm on your page now... I have simulated a couple of cases of relay assistants and conditions on my small Quattro system at home and have concluded the following since my initial reply to you:

In a single relay-assistant instance (one assistant for multiple conditions):

Multiple conditions are ANDed to turn relays on (on relay assistant listed first).
Multiple conditions are ORed (or false conditions are NANDed) to turn them off (off relay assistant listed last). (I can make my small test process and results available).

The delay issue is confusing because it appears that on some conditions there is a delay (test set to 10sec) but sometimes only a 2-3 second delay.

I have not been able to repeat your AC load value discrepancies. There may be a bug in the way the assistants with multiple conditions are written to ROM?

@mvader Matthjis can you help with this? - from Bruce's second last and last paragraphs?

Regards,
Kenyon

Hi

Re Diversion control of surplus PV power. EG Hot water cylinder heating, with a small Multiplus2 3kw 48v inverter with overload control, turn off hot water cylinder when other loads come on. Main house loads are top priority, hot water cylinder is second priority

This is what is have done and tested to date and it's works like this.

Start genset assistant first with inverted relay function open relay, and set loads to suit inverter type, times etc.

Then add programmable relay with off function with low SOC %

Then add another programmable relay on function with high SOC %

Note: If you have the high SOC below 100% any thing above that % will stop the over load function from working and keeps the relay on all the time, in which case you will get a overload warning or shut down etc.


generator start and stop (size:197)

*) Use primary programmable relay to start generator.

*) Open relay to start generator.

*) Start generator when load higher than 1200 Watt for 2 seconds

and stop generator when load lower than 1100 Watt for 2 seconds.

*) The generator is not stopped by AC input.


programmable relay (size:30)

*) Use primary programmable relay.

*) Set relay off

*) when SOClower than 78%.


programmable relay (1) (size:30)

*) Use primary programmable relay.

*) Set relay on

*) when SOChigher than 80%.


Regards

Rob D

NZ

3 Answers
Johannes Boonstra (Victron Energy Staff) avatar image
Johannes Boonstra (Victron Energy Staff) answered ·

Hi all,

Working with assistants works with the following rulws

- an ON condition always has priority over an OFF xondition

- multi criteria in the ON ( Or OFF ) list go by the OR principle


When multi assistant control te same output (such as a relay ) , the outcome of the lowest in the list will be the state of the relay

(So when controlling the relay open with one assistant of which the criteria fits. but close with anther were also criteria fit, it depends which is lowest in the list


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fyi all; I've documented that here:


https://www.victronenergy.com/live/assistants:start#combining_multiple_assistants


If anyone has further improvements; welcome to make a login on that website and change the text yourselves.

Are you able to possibly provide some simple worked examples to help demonstrate & understand the logic functionality?

I think that this would be most helpful for most people including me...

I am afraid I cannot make it any easier.

Beside this, did you see the help text displayed in the start of every assistant?

If you keep the criteria I mentioned in my first reply in mind , it shouldn’t be to hard to make your own logic

Hi Mark,

I'm working on this for my own purposes. As Bruce said, it turns out easier just to do one condition per assistant. Based on Johannes's input I'm not sure how i came to the AND for ON and OR for off.... but i will follow the "rules" and see what happens. There seems to be a conflict at some point. If I manage to find out why I will post here (maybe it is just the way I ordered my assistants (i have about 11 relay assistant instances now..)).

If using relays for the more complex load management I have does not work : I am on the point of building a separate Arduino circuit with MQTT to a CCGX for load management.

Cheers,
Kenyon

Hi Kenyon, thanks for the reply.

I have NOT had time to have a play/test with the assistants as yet, so I agree that's half my problem. I am normally quite good at purposely setting up various 'test combinations' to figure out the associated behavior works & prove/disprove things.

The fact that it treats multiple conditions with OR logic (not AND logic) is clear to me.

The fact that any ON condition being met has precedence over any OFF condition being met is also clear to me.

I also understand that I can achieve AND logic by physically using MULTIPLE Multi relay outputs & physically wire them such that BOTH need to be closed to work. With this arrangement you can easily achieve AND for ON & OR for OFF...

I also understand that I can physically wire a relay output back into an AUX input to achieve particular behavior/logic conditions.

I think that the main aspect that I DON'T fully understand (yet) is the importance of ORDER when multiple assistants are used.

I 'guess' that it does progress all assistants simultaneously, but when 2 assistants trigger the same output, then the lower assistant has precedence? If so when would the 'higher' assistant in the list ever be followed?

Ideally I would like to see 2 examples with the SAME assistants & conditions, but in a DIFFERENT order and with a DIFFERENT final outcome/logic as a result. I think that this kind of example would help me to fully understand the logic & how to work with/around it.

kenyon avatar image
kenyon answered ·

Hi @Bruce.notapple and Victron,

I'm having the same trouble. Sticky or no relay control. I'm using it for load management for a hybrid on-off grid system with a fronius :P Using all 3 relays plus the CCGX relay and one Fronius output...

Some relay assistants are performing but yes, I also need an answer on:

1. Do multiple conditions on a relay assistant get "ANDed" or "ORed" and why do they sometimes ignore delays... or ignore all input?

2. Which direction on the assistant list is priority? I understand top of the assistant list is priority - ESS need to be there to work - i can not find where i read this. I seem to be getting the relays being over-ridden by a high listed relay assistant not a lower listed one? Im convinced it is the AND/OR within the assistant that is stumping me, operation does not seem to be consistent.

3. It would be totally awesome if Victron could add an option on VRM or the CCGX to record relay events with a time stamp and reason for set/clear - will help trouble shooting. there is the email option on VRM for relay event but it does not indicate what triggered the relays and emails are flooding my inbox :D

Kenyon

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Hi,

I tried to get info' on these matters directly from Victron in my area, but they would only refer me to my local dealer. I discussed it with him, but he has either no time to, or luck in, chasing it up.

To Kenyon's specific questions:

  1. There is no way to choose AND or OR between separate assistants. If AND were the default, that would severely limit the functionality of the whole assistants set-up, so presumably it is OR by default, and it appears to be so from my experience.
    That leaves multiple conditions in one assistant as the only way to get AND logic.
    It might be convenient to be able to OR multiple conditions in one assistant, but it's not necessary because you can get the same result by using multiple assistants that do the same thing, each with one of the conditions to be ORed.
    As far as assistants with multiple conditions ignoring delays and otherwise not functioning correctly goes, I can only assume that the software is faulty.
    I have stuck with only one condition per assistant, and I have been able to get them to do what I want, also with delays.
    I achieved a workable AND function with delays by using one assistant to set a relay on one condition, followed by others that clear the relay if the other conditions to be ANDed were false [ie to get x AND y AND z, my first assistant sets the relay if x (is true), the next assistant clears the relay if !y (y = false), and the third assistant clears the relay if !z].

continued ...

  1. .....

  2. I know that 'priority' in the assistants list is mentioned in material elsewhere, with the suggestion that the one at the top of the list has priority.
    My feeling from experience is that the software simply starts at the top of the list and works down though all the installed assistants. In that way the first one would have priority in as much as get processed first.
    I think the order only matters if more than one assistant changes any one relay, flag or other setting. If that is the case then it is the one of those assistants that is lowest on the list that 'has the final say', before the software reaches the end of the list. In that way, it would be more correct to say that the assistant lower down the list 'has priority', but I think it is more helpful to think of it as 'having the final say', as this makes it clearer how the list functions.

  3. Yes, and it would be awsome if Victron would just publicise some solid information about how the assistants work, and what they know functions, and doesn't function!

Hi Bruce,

Thanks for your reply! Thanks for the hint on "reverse" logic I should have thought of that. I am nearly at the point of integrating an Arduino Uno to do the logic...

For my question 1. Confirm your experience is that multiple conditions within one and the same relay assistant are ANDed? - I am trying to experiment with this now.

Cheers.

Kenyon

Hi Kenyon,

My idea that multiple conditions in one assistant are ANDed is really only assumption / guesswork. When I tried to use them, things went haywire, I couldn't work out what was going on anymore, and as I said, I now stick to one condition only per assistant, which seems to work fine.

Cheers,
Bruce

boekel avatar image
boekel answered ·

Yes, the assistants can take some thinking / experimenting. every relay assistant needs a second one to turn off again, except the 'generator start / stop' .


Using the 'generator start / stop' assistant is often the best / easiest way to accomplish what you want to do, and you might have to wire relay outputs to inputs to make things work exactly the way you want.

I do agree the documentation is a bit scarce, but once you get the hang of it the assistants are a powerful feature ('free PLC with every Multi')

https://www.victronenergy.com/live/assistants:introduction

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Hi Boekel,

Thanks for your suggestion re Generator Start and Stop Assistant. I see that it can do a lot, but what it cannot do is read an Aux input, which I need for my insolation sensor.

And, I am indeed using different instances of Programmable Relay to close and open the K1 relay.

I'm sure that I will get the hang of the Assistants, but what I need now is more concrete information, and as you say, documentation is scarce!

I'm in Motueka, New Zealand BTW.

That's why you have to wire the aux input through one of the relays controlled by the generator assistant, that way you create an 'AND' condition, than use the aux input to control AC out 2.