A/c control

[randolph]

Hi guys, using a monsoon x that has ran out of analogue.

i want to setup a strategy to leave the a/c on for 3min then of for 30 sec repeatedly when a/c switch is active in order to not overload the system.

can this be done using the timer and gp aux combined and if yes please do suggest some strategies that could work.

thanks

[DerekAE86]

What inputs/outputs do you currently have setup for the AC system?

Typically an AC system will monitor a Low Pressure valve and a Thermister in addition to the Engine RPM.
When the AC button is pressed the Clutch will only engage if:
1) Engine is running
2) AC system has pressure
3) The system isn't getting too cold

Once it's at cooling capacity it will then regulate the temp monitored by the Thermister by cycling the Clutch on and off for a certain period.
Some older cars had an "Eco" mode for the AC which just increased the freqency/duration of that happening.

So to recreate the same AC control within the Link you'll need the Pressure Sensor/Switch, Thermister and Switch as inputs and the Clutch (Relay) as an output. After that you can easily create a Logic state to cycle the system accurately under the "AC Clutch Control" settings if you change the Mode to "Full".

Trying to do full AC control without a pressure or temp input isn't ideal because your cooling performance will change depending on the ambient conditions and you could damage your compressor if you lose gas pressure because you'd never know.

[randolph]

1 hour ago, DerekAE86 said:

What inputs/outputs do you currently have setup for the AC system?

Typically an AC system will monitor a Low Pressure valve and a Thermister in addition to the Engine RPM.
When the AC button is pressed the Clutch will only engage if:
1) Engine is running
2) AC system has pressure
3) The system isn't getting too cold

Once it's at cooling capacity it will then regulate the temp monitored by the Thermister by cycling the Clutch on and off for a certain period.
Some older cars had an "Eco" mode for the AC which just increased the freqency/duration of that happening.

So to recreate the same AC control within the Link you'll need the Pressure Sensor/Switch, Thermister and Switch as inputs and the Clutch (Relay) as an output. After that you can easily create a Logic state to cycle the system accurately under the "AC Clutch Control" settings if you change the Mode to "Full".

Trying to do full AC control without a pressure or temp input isn't ideal because your cooling performance will change depending on the ambient conditions and you could damage your compressor if you lose gas pressure because you'd never know.

I know it isn’t ideal but i have no analogue or digital inputs left on this ecu therefor want to get it to remain on for three minutes and off for 30 sec,(will play a bit with these period using the a/c pressure gauge to decide on this)

we are in a tropical country and the ambient does not fluctuate that much.

[Adamw]

Mechanical dual pressure switches are pretty common for this type of application.  

Anyhow, this should do something similar to what you ask.  Im replying from a hotel room so havent tested this but it shouldnt be far off. 

Set up your AC switch DI as a GP input.  The GP output will use the on/off delay to do your 3min on, 30s off.  Note however it will start with a 30s off period when you first turn the switch on, and when you turn the switch off it may continue to run for up to 3 mins.  You can get around that by adding another GP output if it bothers you but try keeping it simple first.   Then use the virtual aux as your AC request, this will allow the idle up and clutch delay etc to work correctly.

[randolph]

28 minutes ago, Adamw said:

Mechanical dual pressure switches are pretty common for this type of application.  

Anyhow, this should do something similar to what you ask.  Im replying from a hotel room so havent tested this but it shouldnt be far off. 

Set up your AC switch DI as a GP input.  The GP output will use the on/off delay to do your 3min on, 30s off.  Note however it will start with a 30s off period when you first turn the switch on, and when you turn the switch off it may continue to run for up to 3 mins.  You can get around that by adding another GP output if it bothers you but try keeping it simple first.   Then use the virtual aux as your AC request, this will allow the idle up and clutch delay etc to work correctly.

Adam,

i will this a go and update, thank you