VR Conditioning Board??

[sn95.ohh]

So a few people have mentioned using a VR conditioning board and im having a hard time trying to find out what its purpose is. Does it smooth out the signal going to the microsquirt?? And all the info I find is for the v2.2 and v3 boards but I have a v2.1 board. And since I have a v2.1 board it looks like I have to use a HEI so would I run the HEI inbetween the VR sensor and the conditioning board?? Im a little confused on this whole subject. Sorry im a rookie at all this.

Thanks.

[24c]

OK, your MicroSquirt has its own VR conditioning circuits for the two VR inputs, which are VR1 & VR2 (crank & cam sensor inputs usually).
I don't think I am being critical if I say that there is a conditioning problem with the shared or common ground when using a VR2 cam sensor, as well as the threshold voltage seemingly being too high to detect, in my case, the cam lobe.

The newer almost released v3 MicroSquirt has a revised conditioning circuit based on a MAX9926 chip, and a wiring change at the Ampseal (pin20), to create a separate VR- input. These two changes hugely enhance the conditioning circuit, and transform the VR sensing capabilities of the MicroSquirt.

If you are going down the crank & cam sensor (VR1 & VR2) input, and have the older MicroSquirt, I personally would recommend a VR conditioning board based on the same MAX9926 chip that the v3 uses, as this simplifies and eradicates nearly all the issues I have seen in four years of playing with MicroSquirts on motorcycles. You can make your own, or buy one from here, which I have done a couple of times, and all the board does is process the raw signals from your sensors, cleans them up etc and then you interface these outputs into your Microsquirt. You don't interface the HEI with the VR conditioning board.

The added advantage of these MAX99xx chips is they can easily discriminate false triggers from noise, which can help at higher RPMs too.

Hope this helps.

PS If you are just using a crank sensor with a missing tooth wheel, it is not necessary to use an additional board/circuit, and if you need a cam sensor (sequential etc) some folks have successfully used a Hall sensor for the cam input, because these can easily overcome the 1.8V threshold voltage limit, as generally they use 5V or 12V DC.

[sn95.ohh]

ok got it. Thanks! So I would run wires from the VR sensor to the conditioning board then from the board to the Microsquirt Module into the VRinputs. Ok so since I have a V2.1 module I was told that I would need an external ignition module, how would I hook up an ignition module with this setup??

[24c]

Yes for the first bit, and depends on your external ignition module, but most rely on a 5V signal to trigger, with a 12V and ground feed too. Your 5V trigger is via your IGN1 (& IGN2) outputs, but this is explained in the info pages.

So for example in my 4 cylinder engine, using the 2 Logic Level Outputs in wasted spark mode for a 1342 firing order with my external ignition module, I have IGN1 tied to 1&4, and IGN2 tied to 2&3 cylinders.

[sn95.ohh]

Alright so the HEI would be getting the signal from the ign output from the module.

After rereading the end of your last post you had mentioned if using just a crank sensor I wouldnt need the board. I had planned on using a hall sensor for the cam sensor from the beginning. So with a VR sensor on the crank and a hall sensor on the cam I wouldnt really need the VR conditioning board after all? Unless I went VR on the cam also?

[24c]

...So with a VR sensor on the crank and a hall sensor on the cam I wouldnt really need the VR conditioning board after all? Unless I went VR on the cam also?

Yes

[sn95.ohh]

Great! Thanks so much! You have been a big help. Im slowly figuring everything out. Now I just need to hurry up and buy my sensors so I can wire this thing up!