Electrical Noise Within High Speed Counters?

As you have power ground and signal available at the sensor end, I'd suggest a simple buffer with low output impedance (say 50, 100 or 600 ohm whatever you fancy) at the sensor end. At the other end of the cable terminate the signal wire with a 50, 100 or 600 ohm resistor to ground.
This should help....or maybe just a RC network may match it and kill the noise.

You don't actually say what you mean by high speed...on man's 'high speed' is another man's 'snails pace'.

Give us more detail, spec of the sensor (characteristics of the cable?) and I'm sure someone will be able to give you chapter and verse.

Del

We could be missing important details about your problem.

What's the brand and model of your sensor and your counter? If you can give the specs of your sensor and counter, that might suffice.

You can run a small experiment to find out if your sensor and counter can work together. Just hook them up on your workbench and trigger the sensor with a small motor with a magnet on its shaft.

Another possibility is your sensing distance. If it's exactly at the threshold, vibration could be bringing it out of the sensing distance from time to time.

If you have an oscilloscope, you can view the waveform at the counter's input. If you see noise, there's your problem. If the waveform looks funny, look for the reason. Sometimes a shielded cable will have too much capacitance and tend to filter the sensor's output resulting in a slow rise and fall-time.

Lastly, it might be a simple loose connection. I say "simple" but looking for a loose connection can be anything but. Sometimes, it can be in the most difficult of places to get to.

regards,

Vulcan