question

The exttransferswitch function requires a second digital input be set to 'external transfer switch' mode, and a relay be installed that will trigger that digital input from the ATS when the input switches between shore/grid and generator.

@derrick thomas, I am running v3.31 software. The extternaltransfer switch package says that it is invalid in v3.31.

I found out what I did wrong and your suggestion actually lead me to the answer. I had digital input #1 set to generator. I went back to that setting and checked and found that when I installed Guimods, I guess, an external transfer switch option appeared. When I checked that box, I now have a line in the device list menu that reads External Transfer Switch.

I am sure that the information regarding setting the digital input from generator to external transfer switch is in the Readme files, but I sure missed it. In any event, my system is working and all is good.

As a matter of interest, I had implemented the cooldown functionality using a couple of relays and Assistant programming on the inverters. It worked like a champ until I was forced to update the Cerbo software. Since the new software had the cooldown function apparently emplimated, I removed my relay work around. I was told that my current, at the time, inverter software should implement the new cooldown functionality. That advice was incorrect.

I read somewhere that Guimods maybe going away. If that is correct, I will miss it. I have found the displays to be much more intuitive that what I have seen, so far, in the Victron stock. Also, my wife understands the Guimod displays much better than the stock displays.

Also, the ease of changing input current limits, and the automatic changing of input current limits from current grid-to-generator and then back to grid something that I have not heard that Victron is working on. I use that feature regularly since my grid/shore power input limit change regularly as I travel. Once again, my wife found it easy to remember to tap the grid icon, tap the required new input power setting, and be done with it.

Since I am not a true programmer, I can only guess at how hard it is to implement new, stable, features. I look forward to what many more months will bring.

In any event, thanks again for the help. It is greatly appreciated.

OK, I am confused @derrick thomas. I tested and it appeared to run with only one signal. I will accept that it needs two, but I wonder why? The generator warm up, cooldown, and stop timers should only come into play if the Cerbo knows that the generator is running. And the timers did work. I will test again tomorrow. Just to be sure. I don't mind putting in the second signal, but I am curious.

Also, can I jump the two digital inputs together since I only have one set of signal wires? I have three unused digital inputs so using a second input is not an issue. If I can use the same set of wires to both inputs, then the change is simple. Any thoughts?

Thanks

If you are using relay 1 for auto start functionality you should have a digital input set to 'generator'. I suppose you could use the same signal for a second digital input set to 'exttrasferswitch' but that is not the preferred method. There is the possibility of a situation where the generator is running but not supplying ac power. Having a digital input dedicated to exttransferswitch that is triggered from the ATS ensures that the generator ac input current limit is only selected by the GX if ac power is detected from the generator. This is easily achieved by triggering a relay from the generator side of the ATS which toggles the digital input that has been set to 'exttransferswitch'. The 2 digital inputs serve different purposes and should be fed from the appropriate sources.

OK. Thank you @derrick thomas for the explanation. It makes sense. In my situation, if the generator runs, the ATS disconnects shore power and connects the generator. I cannot run the generator without disconnecting shore power.

I will add the second digital input.

Thanks for the explanation.