MoTeC Global Forum

Could I ask for some advice,

What I want to do is use a magnetic cam sensor on a M4 unit, however the magnet on this setup is fixed to the cam and sweeps past the sensor itself, what have done is set this up on work bench with electric motor with scope reading the output. at perhaps cranking speed am seeing 6 volts idle 12volts and 2500 revs (cam speed) around 70 volts. so is there any possibility of using this setup with Motec? as levels seem very high. Have looked for a hall sensor but due to high heat inside engine think this is a no no.
Thanks in advance, Andy........

If you are getting 70 volts at 2500 RPM you may have problems at higher RPM as it may go over 100V. You could load the sensor up with a resistor so that you get say about 2 volts at idle and it should work ok. You will just have to use a trial and error process to get the required resistor value.

We are introducing a new Hall sensor which is oil resistant and has a temperature rating of 150 degrees.

bbs16 wrote:Could I ask for some advice,

What I want to do is use a magnetic cam sensor on a M4 unit, however the magnet on this setup is fixed to the cam and sweeps past the sensor itself, what have done is set this up on work bench with electric motor with scope reading the output. at perhaps cranking speed am seeing 6 volts idle 12volts and 2500 revs (cam speed) around 70 volts. so is there any possibility of using this setup with Motec? as levels seem very high. Have looked for a hall sensor but due to high heat inside engine think this is a no no.
Thanks in advance, Andy........

If this is a trigger signal just going high and not an analogue signal (Sine wave), then couldn't one use some diodes (Or even a Zenier-diode) to limit, or actually clip, the high voltage peak level?
Then it would start at 6v and go to Xv and stay at that "X" level all the way up to redline.

Thanks for reply Ross B,

As you have suggested have put a 220 ohm resistor across the ouput and this has reduced it to 2volts.
Yes it is a sine wave ouput from this sensor as the copper coil is the sensor itself. good thinking about a zener diode though, have also tried a transformer which has same effect as resistor but bit bulky.