Traction Control and ABS analogue to digital converters

[Chris Wilson]

I have just sold a couple of analogue to digital converters to a member, so I thought he, and maybe others would like to see just what these mystical devices do. Apologies to those who know this already. Some aftermarket ecu's need a digital (square wave) input from analogue devices (voltage out from them comes as a sine wave or plain voltage rise and fall). Some ecu's, as in the case of this customer with a Syvecs, have run short of analogue inputs and need to use an analogue wheel speed sensor signal converted to a digital (square wave) format, on a spare digital input to the ecu. This is what the converters do, take a sine wave, varying frequency, varying output level device and convert the output to a relatively fixed amplitude square wave signal, still varying in frequency governed by wheel speed. The wheel speed sensor sees each tooth on the reluctor ring go by as the wheels turn, and it outputs a signal. This also rises in amplitude with wheel speed.

 

 

Here is a simple set up with my frequency generator outputting 1 volt peak to peak sine wave at 2kHz frequency. The lower trace on the scope shows this, the input to the device. The upper square wave trace is the output from the device, converted within. Free test for the customer, and hopefully of some interest to others

[Nodalmighty]

Yes, I'm interested in these. Are they fast enough to convert VR engine position to Digital hall square wave, do they corrupt the VR signal or can it be sent on to other devices?

[Chris Wilson]

I doubt they are fast enough, but I can test one, what frequency do you want me to test it at?

[markssupra]

Really interesting and helpful info Chris, I checked with Ryan earlier this morning about connecting these converters to the Syvecs, so I know what I need to do now

Thanks for your help as well.

[Nodalmighty]

can you test at 1kz

[Chris Wilson]

The test in the photos was at 2kHz

 

Lets say you use it with a 40 tooth sensor @ 8000RPM, that's 8000 x 40 pulses a minute = 320000 pulses a minute. Divide by 60 for PPS = 5.333kHz. That's probably a worse possible case scenario, how many teeth has the crank trigger wheel got that you are using Nod? I used 40 as a high, arbitrary figure, it'll be less than. Using a Hall effect is surely simpler though?

[Wez]

Nice info Chris and nice lab setup

[Chris Wilson]

Thanks, it's more RF based, but it's fun to be able to show "low frequency" stuff, too

I am well into my radio these days. Yes, I am old, and it's a more sedentary hobby!

That `scope is old,but still a nice bit of kit 500Mhz, analogue.