CKP sensor design with comperator

[studentLab]

Hello, i try to duplicate crank position sensor signal. Here my LM301A circuit with multisim 13 simulator. Need advise to get similar to real signal.

Real signal get.

It is possible to re duplicated the signal condition.?

 

[BobbyPrice]

Add offset and hysteresis to get the switching points correct, and feed the signal into the positive input of the LM301 to get the correct polarity.

 

[(*steve*)]

It looks like the original square wave is simply the result of using the sine wave as input to a schmitt trigger.

The trigger points appear to be +1/3 division and -1.5 divisions. I'm assuming that 0V in in the centre, and I can't figure what the vertical scale is for the sine wave, but I'm sure you know.

 

[studentLab]

Here my new circuit, simulator give almost near.. Add Rd resistor and change polarity, look like same but diffrent output value.

Circuit here:

 

[studentLab]

Inject a sinusoidal signal instead of the sensor and at the output of the hydrid module in Honda OBD1 must have a rectangular signal of the same frequency than input.

Crank sensor signal = +/- 250mV sinus wave
Crank signal after trigger in the module = 5v square wave

So inject +/- 250mV sinus wave the signal out from module = 5v square wave. If Vin frequency 100Hz then Vout also 100Hz. I check up the frequency in and out was same. But Vout trigger not 5v square wave. What should i modidy to get 5V square wave?

 

[KrisBlueNZ]

What's your question, and what are you trying to achieve?

Are you worried that the duty cycle of the output waveform is not 50%?

If so, you need to make sure that your upper and lower trigger points are equally spaced around the centre (0V) line of the sinewave.

That won't happen with that circuit because your op-amp is not powered from a split supply. You need to provide a negative supply rail (e.g. -5V) into pin 4. Without this, the output can't go below 0V.

Your circuit has several unnecessary components and is not very clearly drawn. This makes it hard to follow - for you, as well as for us.

Try using a split supply; preferably more than ±5V - I suggest ±15V. See if that fixes the asymmetry.

 

[KrisBlueNZ]

Are you planning to build this up, or is it just an assignment and you just need to show it working in the emulator?

 

[studentLab]

Are you planning to build this up, or is it just an assignment and you just need to show it working in the emulator?

I try to build this circuit when simulator give most equal to real signal. Not an assignment. I have one Honda OBD1 P30-900 EG9 ecu that have problem with the module that convert CKP sensor signal to main processor. Mostly people just change new ecu or swap the module with another damage ecu that module still working. Maybe if can duplicate the signal can fix the ecu up, just want to try and i can study more how op-amp work.

 

[KrisBlueNZ]

What power supply rail(s) do you have available? I guess you have +12V and +5V?

What is the minimum frequency of the signal from the crank position sensor that you need to be able to detect?