Calculate RPM using a prox. sensor

[smario 0]

I have one proximity sensor which can generate 6 pulse per revision. How can I calculate the RPM? Is PRV2 function available for sensors or only for encoders use? Can me help someone? My PLC is OMRON CP1L-M30DR Thank You in advance Mario

[BITS N BYTES 66]

Use PRV2[883].

[smario 0]

PRV2 function work for proximity sensors?

[pfort 20]

Encoder or sensor, the PLC doesn't make the difference

[smario 0]

i use PRV2 function but the speed rotation don't display a constant (sped rotation oscillating)

[BITS N BYTES 66]

Check the parameters you have entered in the C1 control word and your pulses/rev in C2. You have not specified the max/min rpm of your 6 pulse per revolution sensor. If it is running slow then you will get large variations in speed if you have the incorrect Pulse frequency calculation method set wrong. Third digit in C1 control word. My guess for your application would be to set C1 to #0030 and C2 for #0006. Don't forget the '#' otherwise you will get totally screwed up data.

[smario 0]

for C1 i use #0000 (Standard calculation method), and for C2 #0006 but still oscillating Edited 1 Feb 2010 by smario

[BITS N BYTES 66]

Have you tried other settings for C1? Have you configured "Built-In Input" PLC settings correctly for your Sensor Input. Should be "Use Counter [60Hz]", "Linear Mode", Software Reset", "Increment pusle input" [Don't forget to power down and power up PLC after changing them]? What IS the RPM range of the shaft? Other things to consider:- Switching frequency of proximity switch. Are you operating the proximity switch outside its switching frequency [a very common mistake]? If the RPM is slow and/or the duty cycle of the pulses is not consistent [all 6 pulses should be about the same] then you WILL se fluctuation. In that case you will need to create an average speed over a longer sampling time to smooth out the result.