Rpm

jw5192 · Feb 14, 2012

Hi, looking for the best way to take a 250ppr encoder signal into the 2 high speed counters on an 1100 and convert it to an rpm, what would be the best way to do this?

Thanks

Earthscape · Feb 14, 2012

I've used the Z pulses on an AB to get rotation. Z for one direction, and Z-not for the other. What type of Encoder and Card are you using ?

jw5192 · Feb 14, 2012

The encoder attaches to a motor shaft for testing the rpm of production motors,

widelto · Feb 14, 2012

He is using a micrologix 1100.

jw5192 · Feb 14, 2012

right it's a micrologix 1100 I'm using both the analog inputs for my current an voltage transducers going into SCL.MOV. DIV, scaling.so i need to figure out how to take the high speed inputs work with a hand held accu coder after that all 3 of these will be moved to strings on a panelview plus 600,

The encoder type is of no concern to me i can change it I'm just looking for the 90deg fase shift from channel a and b

Salmanahm · Feb 14, 2012

1- Make a counter that counts pulses from the encoder
2- Make a 6 sec timer that copies counter data to a variable after 6 sec and resets itself and the counter.
3- You have got pulses per 6 seconds now do the maths and convert it into rpm.

jw5192 · Feb 14, 2012

Thank you very much

with the encoder moving at that rate i have adjusted my i/o configuration base/type to bwa base and a filter of 12.5us
trying different configurations in the function file for the hsc
and i still cant get it to accurately pick up all the pulses, any idea what i'm missing?

Thanks

Mark Buskell · Feb 14, 2012

How do you know it is missing pulses. Are you going by looking at the screen. If so what you see on the screen and what is being updated internally are different. Did you time the pulses over a minute and guesstimate what you should have.

Peter Nachtwey · Feb 14, 2012

jw5192 said:
Thank you very much

with the encoder moving at that rate i have adjusted my i/o configuration base/type to bwa base and a filter of 12.5us
trying different configurations in the function file for the hsc
and i still cant get it to accurately pick up all the pulses, any idea what i'm missing?

Thanks

Are you reseting the counter? If so you will lose pulses. NEVER reset the counter!

jw5192 · Feb 14, 2012

I'm guesstimating by looking at the counter maybe i should be looking in an integer file?, what if i took the en from the counter off channel a of the encoder and put that into a scp function and reset the counter every 10sec then did the math from that?

Thanks

OkiePC · Feb 14, 2012

jw5192 said:
...what if i took the en from the counter off channel a of the encoder and put that into a scp function and reset the counter every 10sec then did the math from that?

Peter Nachtwey said:
NEVER reset the counter!

Not the raw high speed accumulator anyway. You should capture the difference in the raw accumulator each PLC scan and sum that with some variable of your choosing, then reset that variable when appropriate.

jw5192 · Feb 14, 2012

GOT IT THANKS!!!

ONE MORE QUESTION WITH PANELVIEW 600 AND A BARCODE ON THE USB PORT BUT I SHOULD PROBABLY START A NEW STRING.

thanks for the help

Rpm

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