Speed signal issues

[Ivaylo Angelov]

Hello,

My drive wheel speed sensor signal/frequency is making me nervous. Up to approx 115 km/h the drive wheel speed (DI3) matches perfectly with the driven wheel speed (DI 1). Above about 115km/h though, the drive speed starts to have spikes of approx +80 km/h above the driven wheel speed. According to the tunng manual, I changed the setting of DI3 from Rising Edge to Falling Edge but the complaint remained unchanged. The driven wheel sensor is an OEM ABS one. 8 tooth trigger wheel. The drive speed sensor is a VR one as well but originally made for reading engine rpm. Its trigger wheell has 8 teeth and is located on the gearbox output shaft flange. 

With this issue I can't set the wheel slip ratio. 

Any advice is welcome. Endless thanks in advance!

Here is link for downloading a log file with the problem:

https://dox.abv.bg/download?id=7fb7c5f2a7#

[Confused]

I've been having erratic readings with one of my speed sensor signals, and I've just now come across this video this evening, partly promoted by your post here!

 

 

 

The TL;DW: of this is try rotating the sensor 90 degrees, the pickup inside it is actually only a small line of magnet, which may not necessarily be perfectly centred, and it might not actually be sensing the tooth well enough.

This might have an impact at your higher speeds.

Once it stops raining, I'll be popping my wheel off and giving mine a rotate - and I'll report back on my findings!

 

[Ivaylo Angelov]

Very useful video! Thanks for that, but it could help me with my future projects. Both my current sensors are VR type, i.e. inductive. The well working is an OEM ABS one. It has visible 3 thin flat metal cores visible that read the teeth. The problem one is ex OEM crankshaft position/rpm sensor. It has one round center core that reads the teeth. I guess it has about 900 Ohm resistanse. Anyway, I learned something new. Thanks!

Also checked the DI 3 signal as frequency. It had the same spikes. It could be signal noise but why only at speeds >115km/h !?

[Confused]

I've just noticed you're in the G4 section, what is the frequency of these signals - it could be that you're over the maximum input frequency if the CPU is getting busy?

[Ivaylo Angelov]

41 minutes ago, Confused said:

I've just noticed you're in the G4 section, what is the frequency of these signals - it could be that you're over the maximum input frequency if the CPU is getting busy?

It appears up to about 480Hz the spikes are missing

According to the text below for turbo speed input, the max DI frequency is 500Hz !!! Is that true?

  A Digital Input can be used to measure turbo shaft speed.  Once configured, turbo speed can be used as an axis parameter on tables.

  Note:  An interface box must be used between the turbo speed sensor and the ECU.  The interface box must have an output frequency of less than 500Hz at full turbo speed

[Ivaylo Angelov]

Please, can anyone confirm what is the max frequency input for the DI channels of G4 Xtreme Red? 

[Ivaylo Angelov]

  anyone.....? Adamw...

[Confused]

@Adamw I too couldn't find anything else in the G4 help about maximum frequency input other than here for the turbo speed.

[Adamw]

Yes 500Hz is the quoted max supported frequency, the actual max will vary depending on how hard the processor interrupts are being used for other functions but the G4 being a 15-year-old processor didnt have much in reserve so you likely wont get much more than 500Hz in most applications.