GP idle (or idle offset) table

[bradsm87]

First impressions playing with the G4X Storm base map file are that these don't quite have the flexibility that I had hoped for or maybe I'm just not looking properly.

I need a switched GP idle table where I can use a 3d map. I thought I could just use the "AC Offset Table" function but that's a fixed single row table and the axis setup option is greyed out and axis forced to coolant temp.

I want to use the winch trigger wire into a DI input and use it to enabled a switched idle target table. An idle target table for coolant temp x battery volts would be fine OR an idle offset table with battery volts as the axis would be OK too. Enabling the ability to change the axis on the AC offset table would be enough. That way, hitting the winch switch with light load can give me a moderately higher idle to start with but when the winch load increases and battery voltage drops, I want the idle speed to come up further.

[Adamw]

Under Idle actuator settings there is a GP Idle source, setting this to your winch DI will enable an offset to the idle valve position and an offset to the idle target if in closed loop.  If you want to take care of battery voltage you can make your main target and base position tables 3D with batt volatge on the Y axis.

[bradsm87]

1 hour ago, Adamw said:

Under Idle actuator settings there is a GP Idle source, setting this to your winch DI will enable an offset to the idle valve position and an offset to the idle target if in closed loop.  If you want to take care of battery voltage you can make your main target and base position tables 3D with batt volatge on the Y axis.

OK yes I think I can work with that. Might come in handy for general high current draw scenarios with lights etc causing voltage to drop too. Thanks.

 

Would it be possible to get a hold time and decay time for GP idle up? If I'm hitting the winch switch on and off quite a lot, I don't want the idle jumping around. A 15 second hold would fix that.

[Adamw]

Try it first and let us know if it doesnt work as is.  Typically for a load related idle up you dont want a hold/decay as if the load gets activated again while it is still decaying from the last activation then the offsets accumulate and you end up pushing the idle higher and higher so the closed loop system will get integral wind up trying to pull it back to target.  There is a new feature coming out soon (I think it is in the next release) which adds a delay on and delay off timer to digital inputs and aux outputs, so I suspect that will take care of it turning on/off too often.

[bradsm87]

1 hour ago, Adamw said:

Try it first and let us know if it doesnt work as is.  Typically for a load related idle up you dont want a hold/decay as if the load gets activated again while it is still decaying from the last activation then the offsets accumulate and you end up pushing the idle higher and higher so the closed loop system will get integral wind up trying to pull it back to target.  There is a new feature coming out soon (I think it is in the next release) which adds a delay on and delay off timer to digital inputs and aux outputs, so I suspect that will take care of it turning on/off too often.

The load side of things will be mapped correctly as a battery volt axis on the idle base position table so PID should hopefully not need to make large changes away from that. The hold and decay request is more for the switched GP idle rpm offset. I really don't want my idle jumping around all over the place every couple of seconds. Nice slow decay would be better because there will be a very good chance that the switch will be re-applied within a second or two. I would try but waiting for the G4X Fury. There would be two things at play,  first being the winch activation switch (and it's not always under load) which would be the GP idle rpm offset (say +800rpm offset) and second being the gradual idle target increase with battery voltage reduction as the winch sees more load. Not having a delay and decay with the load side of things is fine. It's just the GP idle offset switch that would be great to have delay and decay on.

[mapper]

why not using a VA aux to Switch ON and off? You can implement a logic with a Timer, start and reset timer with DI = ON and then VA only turns off if timer X < 15sec.

 

[Adamw]

12 hours ago, bradsm87 said:

Nice slow decay would be better because there will be a very good chance that the switch will be re-applied within a second or two.

That's why Im suggesting it is a bad idea to do it with a hold and decay.  Every time you press the button a new offset would get added on top of the last one that is still active/decaying.  So your RPM will get higher and higher everytime you press the button.  

Mapper's suggestion is the correct way this scenario should be handled, but as I mentioned there is a new delay function coming for DI's so you soon wont even need to mess around with a timer and virtual aux.  Basically, if you do even a short press on the winch button the DI delay off will hold it on for say 10 seconds longer.  

[bradsm87]

On 5/23/2020 at 9:21 AM, Adamw said:

That's why Im suggesting it is a bad idea to do it with a hold and decay.  Every time you press the button a new offset would get added on top of the last one that is still active/decaying.  So your RPM will get higher and higher everytime you press the button.

So that side effect couldn't be programmed out? If something is decaying back to normal and the switch is re-introduced, I'd hope the decay can be removed the moment the offset is applied again. I can't think of any scenarios where someone would want it to build up like that in any application.