MoTeC Global Forum

Hi,

I've been reading some other posts related to this matter but I still have doubts on how to wire and setup the M130 to read correctly the ABS sensors on this car.

Anyone have some info about this? The sensor is a 2 wire that I believe it is a magneto resistive, this is right?

viewtopic.php?f=14&t=22

viewtopic.php?f=11&t=4099&p=20196

Hi,

Before I cover the sensor setup, first off I should raise the fact that we strongly advise against teeing into wheel speed sensors if they are still being utilised by the ABS system, as there is potential for the splicing of these signals to impact the ABS units interpretation of these signals which could potentially affect the ABS from correct operation, which is a safety issue.


A 2 wire sensor wheels speed sensors fall under 2 categories - Passive, or Active.

You have passive, which are variable reluctor or VR type sensors. These has a pernament magnet in there sensor tip, with a coil of wire wrapped around them (which is our two wires). These read a toothed wheel for their signal. Teeth passing by the sensor alter the magnetic field, generating a voltage in the wire. The output of this signal looks like a sine wave.

These sensors are wired in an M1 with 1 wire to a UDIG resource, and the other to 0V. The sensor threshold will be 0V, and the hysteresis will be an increasing value with speed, and should be typically 1/3rd of the voltage output of the waveform at that speed. The debounce will be higher at low speeds, and lower at high speeds.


An active sensor is a magneto reluctor or MR type sensor. These have a module mounted in a substrate. These read magnetic rings (in the case of wheel speed sensors, usually mounted in the bearing assembly. The magnetic ring has alternating polarity, which make the sensor output high or low, resulting in a square wave signal.

Depending on the manufacturer, these either take a 5V or 12V input on one wire, as they are a powered (active) sensor. Some sensors will have a '+' marking on the side of the connector to help identify this. Service information, or measuring a stock car will be required to identify the correct input voltage.

These sensors are wired to the M1 with the positive side of the sensor wired to the correct input voltage, and the other side of the sensor wired to a UDIG resource, with a 220 ohm pull down resistor to ground. The signal magnitude on these sensors can vary a bit, but typically read around 0.5-2.0V peak to peak. A threshold of 1.3V is a good starting point. the hysteresis can be a single value (0.1 or 0.2V is fine), and the debounce can be a single number as well, typically i start with 10us.

Scale should be left as 1.0, sensor teeth will need to be measured, or worked out from steady state driving against a known accurate source. Sample teeth is set according to requirements. (0 automatic, 1 no averaging, >1 the number of teeth you want sampled and averaged)

Pin diagnostic channels are your friend diagnosing any debounce/hysteresis/threshold issues, or calculating values.

Hey not sure if this helps you,
but i collected these things .... .

First you have to find out
which generation of active Wheel Speed Sensor you have.
DF6 (Voltage Signal)
DF10
DF11s
DF11sM
DF11i
DF11iM
VDA
(Have a look at the manual in NL 2021_Diagnosewijzer_ABS_BV_DEF_WEB_v2.pdf,
pictures of signals are very good)

Example DF6


Example DF10


Example DF11i




Like in the other treads already explained,
the Sensor is a two wire, which makes a Current Signal.
Depending on Sensor and "State" the Signal is between 0-7-14-28mA.


Here some links with good explanations
Description in ENG
https://premierautotrade.com.au/news/wh ... ensors.php

Manual in NL, (a lot of information also on pinouts etc.)
Page 9(16) to 12(18)
You can see the Signals from the DFxx Sensors
Link: https://cdn.actronics.nl/uploads/2021_D ... WEB_v2.pdf

Description in GER
https://www.kfztech.de/kfztechnik/elo/s ... sensor.htm

Description in GER (Bosch DF11)
https://silo.tips/download/information- ... ufsschulen

With regards
Oliver

NathanB wrote:You have passive, which are variable reluctor or VR type sensors. These has a pernament magnet in there sensor tip, with a coil of wire wrapped around them (which is our two wires). These read a toothed wheel for their signal. Teeth passing by the sensor alter the magnetic field, generating a voltage in the wire. The output of this signal looks like a sine wave.

These sensors are wired in an M1 with 1 wire to a UDIG resource, and the other to 0V. The sensor threshold will be 0V, and the hysteresis will be an increasing value with speed, and should be typically 1/3rd of the voltage output of the waveform at that speed. The debounce will be higher at low speeds, and lower at high speeds.

Is the above possible with an E888?
I have DF6 style sensors.
I've connected as per above to a digital input and am not getting any signal (both with sensor connected and disconnected from the abs system) also checked via dash manager > monitor channels > oscilloscope.
As a test to rule out sensor issues, I have swapped the sensor from the E888 to a M1 unidig input and there is definitely a signal there (seems to be more resolution with the ABS unit disconnected) unfortunately I don't have any free inputs on the M1 so it can't stay there.

Hi,

What do you have going into the UDig inputs on the M1?

SDean wrote:Hi,

What do you have going into the UDig inputs on the M1?

Hi Stephen,

Engine Sync
Engine Ref
FR Wheel Speed
Rear Drive Speed
Cruise Exit
Rotary Switch
Fuel Composition

I do have 1x AT input free in the M1 or the E888 has 3x AV & 1x Dig

Hi Anthony,

You skimmed through the first paragraph

NathanB wrote:Hi,

Before I cover the sensor setup, first off I should raise the fact that we strongly advise against teeing into wheel speed sensors if they are still being utilised by the ABS system, as there is potential for the splicing of these signals to impact the ABS units interpretation of these signals which could potentially affect the ABS from correct operation, which is a safety issue.

I noticed you mentioned having better signal resolution when you unplugged the ABS unit. I will not give you any further assistance with this, and remind you that splicing into the wheel speed sensor wiring on a still functional ABS unit can interfere with its operation.

NathanB wrote:Hi Anthony,

You skimmed through the first paragraph

NathanB wrote:Hi,

Before I cover the sensor setup, first off I should raise the fact that we strongly advise against teeing into wheel speed sensors if they are still being utilised by the ABS system, as there is potential for the splicing of these signals to impact the ABS units interpretation of these signals which could potentially affect the ABS from correct operation, which is a safety issue.

I noticed you mentioned having better signal resolution when you unplugged the ABS unit. I will not give you any further assistance with this, and remind you that splicing into the wheel speed sensor wiring on a still functional ABS unit can interfere with its operation.

Hi Nathan,

I certainly did read that piece and read it as strongly advise against rather than a strict do not do it so pressed on with testing.
I was so caught up in getting the sensor to work that I didn't even think about the drop in resolution impact on the abs unit so thanks for pointing that out, a bit of a brain fade moment on my part.

I will look to just add in an additional external sensors.