Megasquirt Support Forum (MSEXTRA)

I'm gearing up to complete my awd swap and I've been doing a lot of research on the vw gen1 haldex I would love to be able to control it through the pro the way I'd like to control it is hooking up the safeties through the handbrake and foot brake but then you control the 12 V motor or pump through a generic on off switch that compliments a table that controls a step or output I'm wondering if there is a way to control the bipolar stepper based off of TPS, boost, or whatever works best I'm open for idea... basically I need something little switch the 12 bolt on and then something that will control the stepper through the power curve... is there anyway to do this?

Pic

Maybe a on off at say curtain rpm through a relay to power the pump the my friend suggested a PWM controlled stepper motor output board

You could do some interesting things controlling the pumps and valve with MS:

• Crank the pumps and pressure up when you go into launch mode, then you'd be AWD off the line
• Delay pressure so as not to drag the engine RPMs down on launch (i.e. let the front spin a little bit first) instead of having to do 5k clutch dumps to get all 4 to spin and go without bogging
• Use the traction control to increase pressure -> power to rear instead of killing power
• Zero pressure after a certain gear to save the HP

The fact that they use a stepper motor to control the pressure is going to be a small pain if you are also using a stepper for IAC but plenty of people can build a small circuit that listens on the CAN bus and can run a stepper and 2 PWMs (to totally offload the Haldex controlling signals from the MS) or just stepper and do the 2 PWMs from the MS. I'd be interested in hacking some things together if you are willing to run on the 1.4 code base.

So the pump is on off the stepper controls the pressure that locks the clutch pack. I'm under the impression that I can not use the stepper controls for anything but the iac? I'm not sure how much I can link to it I really don't understand can bus that well and I'd have to build something that communicates with mega squirt

Here are some links


http://www.volkspage.net/technik/ssp/ssp/SSP_206.pdf

http://forums.vwvortex.com/#/topics/3218740?page=1

http://www.dutchbuild.com/index.php/en/ ... controller

http://forums.vwvortex.com/#/topics/2071559?page=1

I think the IAC stepper outputs could be used to drive the Haldex stepper motor. Obviously you would have to go to PWM idle air control if you are currently doing a stepper idle air control, and you would need to check the current draw of the Haldex stepper coils to make sure it isn't too much for the MS.

Do you have a speed sensor hooked up? I'm thinking of this as a first try:

• Inputs for stepper motor homing steps, max steps, etc., basically a copy of what is in the Idle Control menu under 'Stepper Idle'
• A 6x6 table with speed as the x axis and TPS y axis. The z value would be % of max steps on the Haldex pressure motor.
• An input for % steps when in launch mode (so you could lock it up in launch mode while at low TPS and 0 speed vs no clutch pressure when sitting at a stop sign for normal driving)
• Pump output and pump on thresholds. Could be as simple as 1 output that turns on anytime the % steps is > 0 or could later handle separate outputs for both pumps and thresholds for each. (Any more info on the 2 pumps? Is that only newer units? I've read a little about 'precharge', do the pumps perform different functions?)
• Handbrake input and threshold

This basically handles everything mentioned in the dutchbuild link but with more resolution and more 'curves'. This would require code changes of course, but it isn't unmanageable at this point and is probably easier if you are leaning towards a separate stepper control circuit over the can bus. Thoughts?

Anyone else find it odd that the "stepper" motor is two wires?

KeithBoden wrote:I think the IAC stepper outputs could be used to drive the Haldex stepper motor. Obviously you would have to go to PWM idle air control if you are currently doing a stepper idle air control, and you would need to check the current draw of the Haldex stepper coils to make sure it isn't too much for the MS.

Do you have a speed sensor hooked up? I'm thinking of this as a first try:

• Inputs for stepper motor homing steps, max steps, etc., basically a copy of what is in the Idle Control menu under 'Stepper Idle'
• A 6x6 table with speed as the x axis and TPS y axis. The z value would be % of max steps on the Haldex pressure motor.
• An input for % steps when in launch mode (so you could lock it up in launch mode while at low TPS and 0 speed vs no clutch pressure when sitting at a stop sign for normal driving)
• Pump output and pump on thresholds. Could be as simple as 1 output that turns on anytime the % steps is > 0 or could later handle separate outputs for both pumps and thresholds for each. (Any more info on the 2 pumps? Is that only newer units? I've read a little about 'precharge', do the pumps perform different functions?)
• Handbrake input and threshold

This basically handles everything mentioned in the dutchbuild link but with more resolution and more 'curves'. This would require code changes of course, but it isn't unmanageable at this point and is probably easier if you are leaning towards a separate stepper control circuit over the can bus. Thoughts?

Wow Im amazed man! Thank you for your reply as you can probably tell I am still learning the computer and control side of things this is probably something honestly that's over my head and her realistically would be better for me to buy the thousand dollars controller but that being said I do know that with the advance in stand-alone systems and the amount of people that could run the system in the near future it would be nice to implement something!!!


Looking at the unit there is only one pump and then a controller/stepper which is factory sealed I would have to open it up to visually inspect it which I'm not scared to do... in my personal opinion I believe the stepper motor is controlled by the can bus directly somehow every haldex standalone controller that I have researched uses a stepper motor to drive the pump one in particular makes you send the controller in to be set up to run correctly and it does not use the Can bus every other one using can bus

Thanks so much for the pictures there really cool and exactly what I envisioned!!! Now to just get somebody on board to actually write the programming... ps i'm willing to do anything that I can physically do to make this possible

I did some more reading and found more evidence that the controller listens on the CAN bus for wheel speed, acceleration, steering angle, throttle, tach, vss, load and then controls a stepper motor that controls the pressure to the clutches. I haven't found any dissenting opinions that the controller listens for a CAN message containing the value for the stepper motor. This means you should open that controller up and post some pictures so we can figure out where to hook up to that stepper motor! I'm onboard to do the actual programming, and maybe even to help with additional circuitry if needed, we just need to spec it out a bit more before it is time to dive into that. I think the biggest question is whether to use the MS stepper outputs or to do stepper control on a separate board (in other words, with a VW motor, are you using stepper IAC or not? Is it feasible to use PWM IAC?) The MS ECU can handle a lot, it will just come down to identifying what the most important inputs are for the best operation (handbrake, vss or will you want all 4 wheel speeds, Haldex temperature or who cares if it runs hot, boost or is TPS better, etc.)

He's swapping haldex in, probably get away with a few less things than stock.

Wow, wish I would have searched a little more thoroughly, here is a picture, couldn't be any simpler to interface if they all look like this. Break out the 4 stepper motor wires and the 2 temperature sensor wires with a 6 pin weatherpack connector, wire up an Arduino with a motor driver and a can bus chip ($50 or less), and send the 'pressure' value from the MS to the new little controller via CAN.

Paul_VR6 wrote:He's swapping haldex in, probably get away with a few less things than stock.

What do you think, handbrake, VSS and TPS good enough for a first try? Is the black device above the stepper motor a pressure sensor?

Paul is correct there are curtain things that would not be necessary like steering angle... pretty much looking for traction then a taper off to fwd again... for the kind of swap that are being done with these diffs anyway!

This link is probably by for the best after market control for them as a complete stand alone that controls the haldex in the long run is the cost ends up being much more then this I'd probably just go this route since it's had eight years worth of trsting

https://m.facebook.com/story.php?story_ ... 9365097032

KeithBoden wrote:Wow, wish I would have searched a little more thoroughly, here is a picture, couldn't be any simpler to interface if they all look like this. Break out the 4 stepper motor wires and the 2 temperature sensor wires with a 6 pin weatherpack connector, wire up an Arduino with a motor driver and a can bus chip ($50 or less), and send the 'pressure' value from the MS to the new little controller via CAN.

Paul_VR6 wrote:He's swapping haldex in, probably get away with a few less things than stock.

What do you think, handbrake, VSS and TPS good enough for a first try? Is the black device above the stepper motor a pressure sensor?

Paul and Keith you guys rock my research skills apparently suck... so my thoughts are is to have a generic output control the pump which is a 12 V circuit to turn on say at a set mph then at that point the pressure to the clutch pack for the split with the stepper would be load vs rpm

I'm pretty sure the other parts in the controller have to do with the k line, brake and handbrake safety's pure the ssp i supplied

I see the pic with a 4 wire stepper, where is that in the diagrams? There are a few pwm to step converters out there...

Paul_VR6 wrote:I see the pic with a 4 wire stepper, where is that in the diagrams? There are a few pwm to step converters out there...

Apparently hidden lol

I really think this is a solenoid that allows the diff to bleed off fast for the handbrake and brake safety's

Sorry I'm excited so I'm writing a lot.... but Paul might be on to something what about a pwm input to stepper output that way the generic output table might be used? Oh and I would be pretty daft to say most of the vw clan will be using pwm to control idle even with my modifyed engine and intake I used a 5.0 mustang throttle

I think a good algorithm would be:

Look up throttle % vs VSS to get base pressure%, call this X
Handbrake is on? -> Is X > <hand brake limit>% ? If so, reduce X to the <hand brake limit>%
Launch mode on? -> Set X to the <launch mode pressure>% (or during the burnout in 3-step, set X to 0 or the <hand brake limit>)
X is above <pump threshold>%? -> Turn the pump output on, otherwise turn it off
Output the steps or PWM or whatever to set the pressure to X

Later add things only if needed like the temperature cutoff, vehicle brake input (although that is handled by the table lookup if you drop the throttle), solenoid, accelerometers, etc.

I think this handles everything in the CRC Haldex Performance link you posted and is actually more configurable.
Here is the hardware I'd use to make it quick:
https://www.adafruit.com/product/2590 $12.50
https://www.adafruit.com/product/2448 $5.00
https://www.amazon.com/CHENBO-Electroni ... 015W4D9WY/ $9

The code for the Arduino would be about 30 lines, which I already have done for another project; I'm using some of the same stuff to feed EGTs into my MS3-Pro and to do CAN to USB to listen to MS output data.