Dual VR 2.1 and Microsquirt Module 2.2

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Dual VR 2.1 and Microsquirt Module 2.2

Postby the geo » Sat Oct 04, 2014 11:25 am

Salut Jean,

I bought an external Dual VR board from you a month or so ago.
I don't know if you remember, but we both bailed out of Montreal at about the same time this summer.

Anyway, I was hoping that it would fix a problem that Ive got with a 2.0 L VW engine with a built in crank sensor, that's running on a Microsquirt v2.2 module.

my current crank sensor is VR and runs fine up to about 5200 RPM where it promptly looses sync. I've tried a VW hall sensor in place of the VR, but got no tach at all
My guess was that your conditioner board was a possible fix for this problem, after i'd tried various shunt and pullup resistor combos.

I have yet to get a tach reading at the microsquirt with your board.
This either means that I'm doing something wrong, or there's something special about the microsquirt that's not helping.
If you have any hints I'd appreciate it. either for VR or for hall.

Merci et A+

Geraint
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby jbelanger » Sat Oct 04, 2014 12:25 pm

Unfortunately, there is no good input circuit on the Microsquirt module (uSM) for a 5V square wave signal like the one from the dual VR board (or a 5V Hall or optical sensor). You definitely can't use the VR input because that requires a zero-crossing signal. You might be able to use the opto input but you will need to use a 1k pull up to 5V between the dual VR output and the uSM input.

What I do with my own ECU to have a reliable input is to modify the uSM. I don't know if you're comfortable with removing surface mount components but you could make a modification that would completely bypass the on-board VR circuit. That would require removing a diode and a capacitor and adding a small jumper where the components were; you would then use the VR input pin. If you want to do this, let me know and I'll give you more details.

Jean
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby the geo » Sun Oct 05, 2014 4:01 am

Salut Jean,

Merci pour votre réponse, qui me soulage pas mal..... en faite j'avais présumé que j’avais fait quelque choses d’idiot lors de l’installation et/ou ma compréhension relativement limité de l’électronique m’a empêché de trouver la solution.

I have been searching online for a solution for quite a while. I've seen things about surface mount mods to uSM, but it's a big (perhaps one way) step. You seem to have run into this issue before, as well as finding a fix.
This is a massive relief and I'm definitely up for trying your solution!

Some clear instructions would be appreciated. I'm somewhere between "make sure that you hold the soldering iron by the blunt plastic end, not the hot pointy end" and your level of expertise.
Most of the web based board mods seem will refer to specific components by number and i've not seen numbers on the uSM. I'm a driver, not a copilot, so "long 2 left past diode, into hairpin right-tightens" instructions will be most useful for helping me identify what to do.
As the car is now in Europe. I'd like to use the OEM / VW 12v Hall sensor if possible. I don't think that the VR was used over here, so getting a spare might be a bit of a challenge. I have a buddy in Lachine, QC though, so it's not impossible.
Although I'm assuming that the Hall / VR difference will be with respect to the connections to your Dual VR 2.1 board, that I've seen documented elsewhere.

I have also seen numerous comments about the tach inputs on the new / v3 uS "in a box" having been upgraded from those in the v2.2 UsMoudule.
Do these fix the issue that I'm having? If yes, dismantling a V3 uS and swapping the board for my "module" board looks like my plan B, should there be a disaster.
Have they basically built one of your conditioner boards into the V3 uS tach input?

Some background for those that may follow in my footsteps:
The uSM is in a 1990 VW Golf 1 Cabriolet, bought in Montréal, Canada and now in London UK. it has a tuned euro spec 2.0 8v (ADY) engine so is like a North American ABA, but has a counterflow head (actually a G60), like all of the 8v Golf 1s and 2s. This means that it has a 60-2 trigger wheel on the crank inside the block and a sensor mounted through the block, below the distributor location (If you've got this far, you know what i mean). At the moment it's got an ABA VR sensor in the hole.
I chose to use the microsquirt module because i could install it in the original ECU case and keep the vehicle looking "stock". The car works pretty much flawlessly (better than Digifant 2 at least), but has sync loss issues at 5200RPM.

Geraint
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby jbelanger » Sun Oct 05, 2014 6:48 pm

Yes, the V3 uS basically has the same VR conditioner as my dual VR board. And the type of sensor you use has no impact on where the dual VR board is connected to the uSM; the difference is how you connect the sensor to the dual VR board. With a VR sensor you connect VR+ and VR- to the board and with a Hall sensor, you connect the signal wire from the Hall sensor to VR+ and leave VR- unconnected. And if your Hall sensor doesn't have an internal pull up you need to add one (either 5V or 12V pull up depending on your sensor; the dual VR board can handle either without modification).

As for the uSM modification, that will require using the opto input (as opposed to what I mention in my previous post). There is one option I haven't tried but that you could do which is much easier and reversable and should work. You can install a jumper that would bypass the input diode (D4) and resistor (R20). This should allow the dual VR board to trigger the optocoupler. You would simply solder a small jumper to one end of D4 and to the opposite end of R20 as per the picture below (that's not a smiley in the picture but the jumper circled to highlight it):

uSM_jumper.png
Jumper over D4 and R20
uSM_jumper.png (57.21 KiB) Viewed 6818 times


Please note that I have not tried this so that may or may not work.

The modification I have done and that I know works is to completely remove D4 and C26 (the capacitor beside D4) and then put a jumper to completely bypass the opto circuit. The picture below shows what I mean (I used this picture so that you can see the component names):

uSM_bypass.png
Optocoupler bypass
uSM_bypass.png (255.83 KiB) Viewed 6818 times


Either of these will require you to connect the dual VR output to the OPTOIN+ pad on the uSM.

So what I would recommend is that you try the first modification. If it works, good. If not, you could try a 1k pull up on the dual VR output. If it still doesn't work, then you can do the second more involved modification and the first modification will not be in the way since you can simply cut the jumper (and the additional pull up).

Hopefully that's clear enough.

Jean

p.s. I borrowed those pictures from the uSM documentation.
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby dontz125 » Sun Oct 05, 2014 7:42 pm

Slightly off-topic since the OP doesn't apparently care :D It's been awhile since I've pondered this, and I don't have my notes handy - the VR2+ input can be used with the Dual VR without mods, correct? It has a 1.5v bias, so doesn't require a zero-crossing?
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby jbelanger » Sun Oct 05, 2014 7:46 pm

Correct.

The only caveat is for high frequency signals. The filtering will filter out high frequencies. That shouldn't be an issue with single tooth signals but if the pulse is too short, that may be a problem at high RPMs.

Jean
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby dontz125 » Sun Oct 05, 2014 7:51 pm

Thanks!
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby the geo » Mon Oct 06, 2014 1:47 am

Thanks Jean

Fantastic set of instructions!
I should be able to have a crack at this on the weekend at the latest and will post results (of course)

I'll try your simple mid first, as that is the path of least resistance :?

Geraint
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby the geo » Mon Oct 06, 2014 3:22 am

Hi Jean

Just to be sure, the output from your board goes to opto in+ /pin 19 on the USM not opto in- / pin21.
Is that correct?

I used an ACD Spare input for a knocksense and lost about a day, before I figured out that the lables on the board and the firmware had ADC1 and ADC2 flipped

So really just checking.

Geraint
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby jbelanger » Mon Oct 06, 2014 11:20 am

the geo wrote:Just to be sure, the output from your board goes to opto in+ /pin 19 on the USM not opto in- / pin21.
Is that correct?

Correct

the geo wrote:I used an ACD Spare input for a knocksense and lost about a day, before I figured out that the lables on the board and the firmware had ADC1 and ADC2 flipped

I don't remember ever seeing that mentioned but that seems to be the case. Annoying indeed.

Jean
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby the geo » Mon Oct 06, 2014 4:03 pm

I don't remember ever seeing that mentioned but that seems to be the case. Annoying indeed.

Jean


Sir, you are a master of understatement
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby the geo » Sat Oct 11, 2014 9:52 am

Hi Jean

I tried your 2 mods and have not yet got a tach signal with either, so I'm not sure what's going on.

Either I've done something fundamentally daft, or there's a more complex issue going on
I also tried swapping VR+ and VR- to the Dual VR and also got no trigger.
could I have toasted your board? Is there any way to check without a scope? should I have tried using VR2 Out2 just in case?
I did check that, with D4 & c 26 removed / jumpered, there was continuity between the jumper and the Out1 pin of the dual VR.

I have put the uSM back to the way it was (a bit fiddly that) and the car runs.
I don't know if that helps. well it helps me avoid getting a parking ticket, which has to be good news!

This probably means going back to basics.
any hints on where to start would be appreciated.

A+

Geraint
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby jbelanger » Sat Oct 11, 2014 12:34 pm

It is possible that the board is damaged. The second mod would definitely work if there is any signal out of the dual VR board. However, you may not get an RPM reading if the signal is not what the uSM expects. Did you check if there was anything in the composite log in TunerStudio? This would show the signal seen by the CPU even if you don't have an RPM reading.

One way to check the board is to connect a 5V or 12V square wave signal to VR+ (I use a JimStim tach signal), leave VR- unconnected and put a LED between Out and ground. You should see the LED flash if the signal is not too fast.

Jean
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby the geo » Sat Oct 11, 2014 1:42 pm

Salut Jean,

I was looking at the trigger log and tooth log whilst cranking.
would that not be the same as the comp log?

Realistically i don't think that I've cooked your board, but is there a way to check without a JimStim?

Geraint
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Re: Dual VR 2.1 and Microsquirt Module 2.2

Postby jbelanger » Sat Oct 11, 2014 1:57 pm

Geraint,

You can use anything that will give some sort of PWM signal (5V or 12V). You could even use on of the uSM outputs and the test modes. For example, you could use an ignition output to generate the signal you would connect to VR+; if you use a long dwell and low RPM you should be able to see a LED flash at the output of the dual VR board.

And you can test both channels of the board that way. You can even test VR+ and VR- independently. Connect only VR+ or connect only VR-: you should see the LED flash in both cases. The difference is that the output signal is inverted when using the other input. So to completely test the board you connect a LED to the output and test VR+ then VR- and then do the other channel. You may also want to test that you don't get an output signal on the other channel when you have an input signal on one channel: I have seen this crosstalk once before and that messes up the signal.

And you should have seen something in the tooth log if there was anything to be seen.

Jean
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