Posted ByCK on January 13, 2002 at 03:18:15:
In Reply to: magnetic pickup posted byChris Johnson on January 12, 2002 at 13:20:24:
If you have a noisy incoming signal, then you need to do something to condition the signal and filter out the noise. As long as the noise signal is strong enough to flip a logic state of the PLC input it will be picked up by the PLC as a valid input and perform measurement of its frequency.
You should attach an oscilloscope to observe the signal from the sensor. Manually turn the flywheel slowly and observe where the signal peaks and troughs. Sometime the sensor senses a wider range than the width of the flywheel teeth, in that case the signal never weaken sufficently to be received properly as an off state and you will not be able to measure the frequency properly.
: I am trying to read engine RPM by sensing flywheel teeth using a Dynalco M203 magnetic pickup. I have tried using PM1 to measure frequency of signal but I get alot of noise.
: I am using a T100MD1616+.