Wheel speed maximim frequency?

[dnb]

Has anyone found the wheel speed signal can't cope with a frequency higher than 1096Hz?  On my bench test rig I can get the wheel speed to function, but unless I limit the input frequency to less than 1096Hz I get aliasing effects followed by zero speed displayed.  The divider and pulses per 100km/h work as expected.

The divider doesn't help because it's implemented after the pulse counter stage, so it just reduces the range of speed displayed in VEMStune.

I really need something to work to at least 4kHz.  Am I missing something in the config or do I have to build a hardware divider for the input?

Thanks

[rob@vems.co.uk]

I would hazard a guess that its the max speed you'll see as the speed sensor is connected to the IO that was used for keyboard input, I'm guessing a hardware divider is required.

[GintsK]

Did you scoped input pin? Could be that low-pass filter cut amplitude. Just a guess.

Gints

[dnb]

I did scope the input to the ECU.  It remained at a good signal level all the way to 5kHz.  I'm using the speed signal to control the epas system too.