Sample waveform for Vauxhall Insignia Active ABS Current?

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Sample waveform for Vauxhall Insignia Active ABS Current?

Postby Columbus » Tue Sep 01, 2015 7:30 pm

As per the title does anyone have an Sample waveform available for an active abs sensor on a Vauxhall/Opel insignia. Don't think it matters but this is a 2010 1.8 eco wreck engine.
Thanks Very much
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Re: Sample waveform for Vauxhall Insignia Active ABS Current

Postby Robski » Tue Sep 01, 2015 7:42 pm

Why do you have a bad one (capture) ?

What do you expect the current to be ?

If only one corner is at fault then surely a good reference can be taken from a corner with no fault :?

I would expect 7-14 mA switching.

How are you measuring the current accurately ?
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Re: Sample waveform for Vauxhall Insignia Active ABS Current

Postby Columbus » Tue Sep 01, 2015 8:04 pm

Hi Rob
i have the same spec for current as you but after a lot of messing around failed to get anything of any use tried taking reference from the other side but getting bog all. Is the standard low amps clamp capable of picking up such a small signal? i had it set to 500mA but seem to only get back ground noise. 60 amp clamp on 20 amp setting.

cheers
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Re: Sample waveform for Vauxhall Insignia Active ABS Current

Postby Alan » Tue Sep 01, 2015 8:08 pm

Sub 20mA is asking a lot from a 60A clamp but its just about possible.

If there is any slack cable wrap it through the jaws several times - if you can get 10 turns then the clamp sees a switching between 70mA and 140mA rather than 7 and 14. Dont worry if you can not do this 10 times - 2x is better than 1.

Try also using the resolution enhance option in the channel options drop down - go for about 15 bits and turn up the memory depth to say 10M. If you have a PicoScope 4425 then also turn on the low pass filter.
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Re: Sample waveform for Vauxhall Insignia Active ABS Current

Postby Columbus » Tue Sep 01, 2015 8:13 pm

Is the 30amp probe a better option then Alan don't think i have much chance of looping but will give it a go tomorrow. I did have low pass filter on i will try and implement the other suggestions. Thanks
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Re: Sample waveform for Vauxhall Insignia Active ABS Current

Postby Alan » Wed Sep 02, 2015 6:19 am

I will see if we have any active ABS waveforms from the 30A clamp and let you know, but it will still be close to the limit of what the clamp can do. The problem is that clamps designed to measure under 1A are expensive and will not get much use.

If there is not much spare wire to loop then another option might be to disconnect the sensor and use the universal break out leads to add a bit more cable.

Another option is voltage - depending on the system you will see a fixed voltage (12V, 5V). Assuming its a 2 wire, measure both sides using 2 channnels with the 2 ground to vehicle ground / battery 0V. Switch to AC coupling and a small voltage range (say 50mV or leave it in auto). Spin the wheel and you can usually see a small square wave as the sensor switches.
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Re: Sample waveform for Vauxhall Insignia Active ABS Current

Postby PicoPhil » Wed Sep 02, 2015 12:30 pm

Just looked on the Waveform library and we do not have a waveform on this vehicle. Will have to get a vehicle and capture this sensor. I have contact a friend who works on Vauxhall and he does not have anything either.
Sorry.
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Re: Sample waveform for Vauxhall Insignia Active ABS Current

Postby Columbus » Wed Sep 02, 2015 10:36 pm

well decided to go oldschool and remove sensor as i couldn't get a trace cleaning an refitting seems to have solved the fault for the moment. thanks for the help every one still going to look for a low amp clamp as active abs sensors are bound to be more and more common. thanks again
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Re: Sample waveform for Vauxhall Insignia Active ABS Current

Postby PicoChris » Thu Sep 03, 2015 8:19 am

If you are unable to uncover enough wire to get a number of turns round the current clamp then you can still get a reading using the low pass filter and some channel gain. The attached waveforms shows the output of the TA018 and TA234 current clamps measuring the current through a 1K resistor with a 6V square wave applied at 10 Hz and 100 Hz. Note both current channels have 10 x channel gain applied.

From this you can see that it is possible to resolve low current signals with either clamp but the TA234 is much lower noise and so much more likely to be discernible when looking at signals in the real world where there is typically more noise around. The other key difference between the two clamps is frequency range. With the TA018 you will find it hard to measure small currents at more than about 50 Hz whereas the TA234 can go much higher to at least 1 KHz. This means that while you should be able to pick up the ABS sensor when turning the wheel slowly by hand with the TA018 you would need the TA234 for normal road speeds.

When looking at slow pulse signals I would recommend a low pass filter set to around 10x the frequency you are looking for as a starting point. You may well need to subsequently adjust this up or down to get the optimal display but it’s a good rule of thumb to start from.
Attachments
sample waveform ABS sensor.psdata
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100Hz sample waveform.psdata
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Re: Sample waveform for Vauxhall Insignia Active ABS Current

Postby Fat Freddy » Sat Sep 05, 2015 7:53 am

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