Wheel Speed Sensor - Passive Inductive Sensor Wiring Setup

Good day,

An FC3S RX-7 that has the ABS removed but still has all four wheel speed sensors, they are a Passive - Inductive type sensor.

I I understand this as the teeth pass the sensor the sensor generates an Alternating Current (AC) Sine Wave.

In this case I will be using an EMTRON Shadow 8 to connect these to in order to enable launch control, and traction control, and maybe even Cruise Control.

I Know that DI 1-4 have the built in Oscilloscope, so my plan was to connect those for each wheel speed sensor, the other lead of the sensor should be connected to ground, but not sensor ground (Ref)? This way I can use the Oscilloscope to tune the signal as required.

As for the setup of the actual sensor in EMTRON -

Sensor Type: Magnetic

Active Edge: Both (because a sine wave is both above and below datum?)

Pull Up: none

Scalar: Number of teeth / wheel diameter (of the tone wheel?)

Channel Assignment: which wheel the sensor is on.

I have done quite a bit of research on this, and the best I can come up with was this;

EMTRON Magnetic-Resistive Sensor WiringWhich was helpful, but did not answer the questions highlighted here.

Any clarification of red text or anything that I may have incorrect would be greatly appreciated, Thanks!

Ok, After removing, measuring, and scoping the FC (FC3S) RX-7 Wheel Speed Tone Ring and sensor I got the following;

Type: Magnetic

Active Edge: Falling

Pull Up: Off

Scalar Wheel Speed: 4529 (225/55R16)

Scalar Tone Ring Speed: 20155

The Tone Right has a diameter of 142mm with 90 teeth and a duration and gap per tooth of 2.5mm each.

Arming Threshold

30mv was the lowest value the scope had a stable wave form; Which got me a on greater than 0.03v and off less than 0.025v

The EMTRON Shadow 8 ECU utilizes the Trigger Ground Pin A7 where the negative pins of the reluctors will be connected to. Otherwise they should be connected to the ECU ground if the ECU does not have a dedicated Trigger Ground for this purpose. I have also attached a couple images of the waveforms.

DC WaveForm

AC WaveForm