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Looks like the kind of sensor that would pick up from a gear wheel or similar.

Regards, Tony

Some of the Italian ink mixers have a similar set on them. The prox sensor picks up off a gear or other protrusion, bolt heads, index plates and reads out. There are often different inputs for X1, X10 depending on if it's a once per rev sensor etc

-- Regards,

John Stevenson Nottingham, England.

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Magnetic pickups need 3 - 5mm clearance, less if the magnet is weak.

We used similar things on Barber-Colman and Ambach (American Bosch) electronic governors, the pickups ran on the starter teeth with about 1/8" clearance. You have to watch out for swarf off the starter ring though....

Peter

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This looks to be 'take it or leave it' one impulse per rev.

Thanks

Tim

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Is this likely to be magnetic? I had assumed capacitative, but then I know nurthing about these things.

Thanks

Tim

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From what I remember (I'm sure others will correct me if I'm wrong) there is an easy way to check.

If it's an inductive sensor it will only pick up metallic objects, if it's a capacitive sensor it will pick up all sorts of objects, and capacitive sensors can also be 'tuned' to ignore objects, like detecting a level through a sight glass, and ignoring the glass.

Believe it or not I used to design a lot of special-purpose machinery about 15-20 years ago and used a lot of these inductive proximity sensors from the likes of Festo, SMC, and others to feed signals into a PLC controlling solenoids and relays..

Then about 5-6 years ago I developed a kind of electrical/electronic dyslexia (or amnesia) and struggle with even simple wiring now:(

Occasionally I remember things, but given the above you may want to take any advice from me with caution .

Peter

Most likely an inductive proximity sensor. A coil inside the face forms part of an LC oscillator, which oscillates at high frequency. An eddy current will be induced in any conductive object within the changing magnetic field (gear tooth, metal peg, etc). This drains energy from the oscillator: a detector circuit senses the dip in amplitude and changes the sensor output voltage. Range should be 2-5mm at least, resolution should be less than the radius of the face - see what results you get from holding it near a rotating gear. You may need to make a cam to clamp on the spindle to get 1 count/rev.

If it's a capacitive sensor it should pick up non-metallic objects with high dielectric constant - eg. your hand :)

hth Guy

Peter,

Just to make you feel happy your not wrong, we use capacitive sensors to detect water inside a plastic tube and you can tune the sensitivity of them. Watch out if the water leaves a crud line as the sensor will see this and make you think there is liquid when there is not.

OK, let's assume it's an inductive job, not ideal for the job I had in mind. What would be the prospects for replacing it with, say, a photoelectric sensor to run from a bit of shiny tape? It looks as though the unit can be adjusted to respond to an input signal of between 100mV & 45V, & there are various outputs available as shown in the pics.

Thanks

Tim Dutton Dry-Dock Traditional & Modern canal craft repairs Vintage diesel engine service