Corsa C epas info
Discussion
I'm chasing a bit of information about the Corsa C column. I have fitted one in my Griffith 500, and it works nicely about 50% of the time. However for some reason, it fails to turn on sometimes.
I have tested my RPM, multi-timer and speed source unit (made from an AVR microcontroller) and it seems to be working reliably and doing what I expect. The snag is that I am not 100% sure what the steering ECU is actually expecting, so if anyone has words of wisdom, I am all ears.
The large gauge wires are obvious - power and ground.
The signal wires in the white plug are less obvious. Here's what I currently think they are:
black: ignition switched +12v (that was obvious, wasn't it
)
red/white: "multi-timer emulator" - supplied +12v a 10 seconds or so after the ignition is turned on so the unit is not powered when cranking.
green: RPM signal. 0v to +5v square wave at constant 350Hz. (I think this equates to a Corsa engine running at 1200 RPM) In the final solution this will switch to a 0v constant signal if the battery voltage drops below 11v, but I have disabled this feature for debugging.
blue/red: Road speed signal - currently a fixed 0v to +5v square wave at 200Hz signal for debug, but will be derived from the TVR speedo such that the assistance profile is what I want. (Again, let's keep the test case simple)
brown/white: Diagnostics connector - connected to an input on the micro controller. Not actually used for anything yet.
I would prefer to not purchase an interface box, because none of them actually do all of what I want.
What am I missing? I suspect I am using the column incorrectly somewhere along the line. Does the wheel have to be centred before the unit will initialise? If so, how do I know where the centre position is given it's in the wrong car and has been whirled round lots of times during installation...
Thanks for anything that'll shed light on the problem.
I have tested my RPM, multi-timer and speed source unit (made from an AVR microcontroller) and it seems to be working reliably and doing what I expect. The snag is that I am not 100% sure what the steering ECU is actually expecting, so if anyone has words of wisdom, I am all ears.
The large gauge wires are obvious - power and ground.
The signal wires in the white plug are less obvious. Here's what I currently think they are:
black: ignition switched +12v (that was obvious, wasn't it
)red/white: "multi-timer emulator" - supplied +12v a 10 seconds or so after the ignition is turned on so the unit is not powered when cranking.
green: RPM signal. 0v to +5v square wave at constant 350Hz. (I think this equates to a Corsa engine running at 1200 RPM) In the final solution this will switch to a 0v constant signal if the battery voltage drops below 11v, but I have disabled this feature for debugging.
blue/red: Road speed signal - currently a fixed 0v to +5v square wave at 200Hz signal for debug, but will be derived from the TVR speedo such that the assistance profile is what I want. (Again, let's keep the test case simple)
brown/white: Diagnostics connector - connected to an input on the micro controller. Not actually used for anything yet.
I would prefer to not purchase an interface box, because none of them actually do all of what I want.
What am I missing? I suspect I am using the column incorrectly somewhere along the line. Does the wheel have to be centred before the unit will initialise? If so, how do I know where the centre position is given it's in the wrong car and has been whirled round lots of times during installation...
Thanks for anything that'll shed light on the problem.
Very useful info there. Thanks. I'd like to see the wiring diagram when you find it.
As far as I can see, the multi-timer thing is not all that important - you can tie the wire to the same +12v as the ignition feed. Since I have a small battery I didn't want to make yet another reason for failed starts. (That's a long story)
It would seem I need to make the speed and rpm signals go from 0 to +12 instead of +5. Annoying, but not hard. It would also seem I need to make sure the torque sensor is in the middle of the range before it'll start. I didn't know that before.
As far as I can see, the multi-timer thing is not all that important - you can tie the wire to the same +12v as the ignition feed. Since I have a small battery I didn't want to make yet another reason for failed starts. (That's a long story)
It would seem I need to make the speed and rpm signals go from 0 to +12 instead of +5. Annoying, but not hard. It would also seem I need to make sure the torque sensor is in the middle of the range before it'll start. I didn't know that before.
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