General Outputs

mrbill · Post by **mrbill** » Sun Jun 11, 2006 5:55 pm

I have an option to use all the fun outputs MS offers, but what kind of outputs are these?

Basically I want to run a relay (actually two) to my E-FANs. I got these two electric fans from my buddie's wrecked Porsche 944, and Id like to do something like one turns on at 170 degrees and the other at like 195.

So what does megasquirt output? A ground, like the fuel pump pin? or a 12v that would be the switch for the relay?

I dont use the idle stuff, so If I were to do Fidle and IAC1, I would do both with the same variable (coolant) and have the thresholds at 170 and 195, each with a 10 degree "hysteresis." From there, I don't quite understand the "power-on value" and the "triggered values"

I apologize if this is the wrong board:(

krisr · Post by **krisr** » Sun Jun 11, 2006 6:10 pm

I run a 'sequential' thermo fan setup now as I need to run 3x fans.

2 x 12" fans switch on at 170, hysteresis of 3.0 (Fidle O/P)
1 x 14" fan switches on at 175, hysteresis of 5.0 (Warmup O/P)

Running a milodon 160 thermostat.

I used the FIDLE output to control the relay for the 12" fans but I upgraded the transistors for the 3 x LED's to 2n2222, jumpered a wire from centre LED to SPR3 and then configure/wired it up to ground the coil of a relay.

mrbill · Post by **mrbill** » Sun Jun 11, 2006 6:33 pm

I am happy just using the idle stuff for now, but when you used fidle, when it turns on, what happens? Like does it GROUND or does it switch to 12v for a relay to click on?

I want to know how to wire the relay with megasquirt. For the fuel pump, the wire grounds, so the relay can "click" on when megasquirt is on. If megasquirt isnt on, the fuel pump isnt.

So does fidle throw 12 volts, a ground, some other voltage? Ya know?

Thanks for the quick reply sir:)

krisr · Post by **krisr** » Sun Jun 11, 2006 7:20 pm

The FIDLE and LED outputs will pull the pin to ground if triggered value is set to "1", i.e. all the conditions are met. I have no idea what the IAC pins will do as I use them for the stepper motor. Can't help there.

I think the way Lance described it in the docs (http://www.megasquirt.info/ms2/spare.htm) should be your best reference on how to use them.

In any case, here are how I set my outputs and I told a lie, I actually used the Accel LED, not warmup. As you can see though my fans will not kick in below 300rpm and below 170/175* coolant. I don't want that excess draw from the fans when cranking, no other reason.