MoTeC Global Forum

Hi all,

Sorry if this sounds n00b but...

I was going thru the aux output parameters when i noticed "Polarity". I searched the internet for the definition and checked the motec seminar notes but am still confused with it versus output mode.

eg: i have aux 7 to thermo fan... when engine temp goes up, output switches to high..which is +12V, relay activates and tada...fan turns on. But what does "polarity" got to do with anything?

Thanks for any help in advance

Am in process of changing from M4 to M400 and think am seeing something similar The output seems to give a choice of do you want the ecu to provide an earth as an ouput or a battery?

anyone?

Polarity swaps On off conditions for the output.

If the table makes the output active you can then swap between the output being on or off.

IDP wrote:Polarity swaps On off conditions for the output.

If the table makes the output active you can then swap between the output being on or off.

Thanks IDP..

wasnt quite convinced at first..so i spent some time with the car running and turning on and off the fans

lemme see if i got this correct..using the example of my thermo fan.. the relay is such that it needs a +12V to activate the solenoid..

on temp : 88 deg
off temp : 80 deg
Polarity 1 (activate high when active)
Output: 0 (switched to ground)
This means...before temp hits 88 deg.. output is 0V, once it reaches 88deg, output is +12V and stays at +12V.. until temps dropped past 80 deg, then output becomes 0V again, right?

but if i wired my relay the other way round, then i need to set
polarity 0
output: 1
ya?

but why are there 2 options and 4 combi? wouldnt it be simplier to just have "Polarity" ?

Dear C4aos,

Polarity is needed very much as well as output! I dont wanna even think to be without those options!

Polarity you can consider also as NO or NC, so you can choose the way how to have it and also give you more space for safety or way of wiring.

As for output, what if you wanna run fan over the ground or over the plus, relay? Just choose it man! MoTeC have one of the most flexible software's in the world! And i hope will keep it this way!

Cheers Pascal

hi Pascal,

so for "Polarity" which is NC and NO?

cos for the example of my thermo fan.. changing "output" didnt always reverse it... *puzzled*

Correct me if I'm wrong but I thought polarity was a table thing ie: if you enter 100/0/0/0/100 it would be on/off/off/off/on reverse the polarity and it's off/on/on/on/off.

Hi Guys,
Just to clear up any confusion.

Polarity: Is the logic of the function, does the ECU activate the output to turn the device on or does the ECU activate the output to turn the device off.

Output Mode: Does the ECU provide 12v to a relay coil that is permanently connected to ground or does the ECU provide a ground to a relay coil that is permanently connected to 12v.

Clasically, thinking of a fan, a relay would be setup so that its coil is alway supplied with 12v from the car when the ignition key is on and engine running (say). To make the fan work the ECU output "activates" and connects the relay coil circuit to ground and the fan comes on, this is the way we would prefer all relays to be wired as the ECU has an easier time sinking the current through to earth rather than having to supply current out. If the fan relays coil was permanently connected to ground in the car then the only way to make the fan run is to send 12v out of the ECU when the ECU output is activated. This is the "output Mode" of the ECU output.

Let now say that the fan relay is setup so that the fan was running all the time when nothing was done to trigger the relay coil and the only way to turn the fan off was to activate the coil, this is the polarity. Normally the polarity is quite logical, if you activate the ECU output controlling the fan the fan comes on and if you were wiring a car this is the way I would assume everyone would think, however the car manufacturers often do illogical things which is why we have the option in the software.

I hope this makes it clear.

Thanks for the info mark... actually, thanks to the info in the software..i'm still confused

my fan relay is connected permanently to ground and needs a +12V from ecu to turn on. So my polarity is set to 1 (does this mean activate output to turn device on?) and output to 0 (i measured and output is constantly 0 until activation then output is +12V)

Polarity: Is the logic of the function, does the ECU activate the output to turn the device on or does the ECU activate the output to turn the device off.

Output Mode: Does the ECU provide 12v to a relay coil that is permanently connected to ground or does the ECU provide a ground to a relay coil that is permanently connected to 12v.