Need Your Technical Support

Quote from OP: "One thing is that the original transmitter metal is no longer there I used a piece of aluminum."

WHAT? If this is a variable reluctance speed sensor, that needs either a ferrous metal target, or magnet target, not piece of aluminum. If the hex bolt heads are not working as target the air gap must be too much. OR you need a magnet as a target. The one from your hard drive head positioner will work real good.

Did you read the manual for the product to see the installation requirements? Did you adjust the air gap correctly? The new sensor should have some sort of technical data provided. But I suspect it needs to have an external magnet as a target else the bolt heads would be seen, as you are seeing slower RPMs as there are many more pulses per revolution if the hex head bolts, are providing pulses. How slow is low speed? Since your reading zero, I again suspect you need a magnet, as with magnetic induction the rate of change of flux is what induces a voltage/current into the pickup coil.

ignator

Thank you, Ignator

I think you right, the target is magnet or ferrous metal, I taught about it at the beginning but later when I spoke to the sensor manufacture they advised aluminum will work that why I went with aluminum. Except that the gap in the datasheet is 0.8mm and managed to get that. I will do what you said and comeback to report the outcome. Thank you again.

Instead of technical support, ring the Managing Director instead.

I just have to confirm to you that the machine is now working 100% after few mail with the manufacture.
The problem was that, the machine have 12 bolts so the sensor will count the 12 bolts to complete 1 revolution. I cleaned all 12 bolts and adjusted 0.8mm, so now it is ok.

THANK YOU ALL.