PPR to FPM

[BARSCO]

I have a system with a 1000ppr hollow shaft encoder on an 8 inch diameter roller. I have the encoder connected to a hsc of my PLC. I am trying to figure out how to program the encoder pulses to allow me to display feet per minute. I thought this would be simple but my attempts have failed.
Knowns: 1000 ppr 8 inch diameter roller (25 inch circumference) this should give me .025 inches per pulse.

From here is where I seemed to get lost. Any ideas? :

 

[Steve Bailey]

You can't do it with only encoder pulses. You need pulses per unit of time. Read the documentation for the PLC's HSC to find the address or tagname for pulse rate and use that.

Divide pulses per second by pulses per foot to get feet per second.

 

[Helliana]

Doing as Steve said and finding the frequency or rate feedback from your HSC card is by far the best and most accurate approach. However, that may not be an available option. If it is not, you can use a timer to count the number of pulses over a period of time and the convert that to pulses per minute and then on to feet per minute. You will have to play your sample time to get a resolution, accuracy, and update time that is acceptable for your application.

 

[RussB]

Amazing!
Do schools not teach those concepts of math any more?
Will "Common Core" fix this?
Saved by the "Internet": http://ctcmath.com/how-it-works/?gclid=CILAotucscACFQwV7AodnTgAYA (Again!)

 

[BARSCO]

Thanks Steve and Helliana. Both were very helpful. Did not need the condescending note from RussB. I guess they don't teach manners in school anymore as well.

 

[danatomega]

+1 on dissing the condescending note...

 

[BARSCO]

+1

 

[Phrog30]

Amazing!
Do schools not teach those concepts of math any more?
Will "Common Core" fix this?
Saved by the "Internet": http://ctcmath.com/how-it-works/?gclid=CILAotucscACFQwV7AodnTgAYA (Again!)

What purpose did your idiotic response serve??

Also, I don't believe you even know what common core is. Common core is a set of standards, not curriculum. Most people don't have a problem with standards, it's the text books. Hopefully that didn't go above your head!!

James

 

[RussB]

Amazing!
Do schools not teach those concepts of math any more?
Will "Common Core" fix this?
Saved by the "Internet": http://ctcmath.com/how-it-works/?gclid=CILAotucscACFQwV7AodnTgAYA (Again!)

Okay.
My humble apologies for all of you with thin skin.

But it was not meant to be condescending.

It just amazes me the apparent lack of education I see coming out of our school system today.

And I have looked deep into "Common Core". You may believe what you want about it but it will further "dumb-down" all who partake of that "set of standards" without major adjustments at the local level.

Go ahead bash away, but please do not attempt to apply for a PLC programming job here until you understand the relationship between leaner measurements and time which "should" have been taught in Jr-High or before.

Now go back to work! ...and Pray that the good 'ol USA survives those "Standards"

 

[rdrast]

+1 to Russ.

Too many questions here are about grade-school basics, seriously.

Even just looking at the unit - "FPM"... 'Feet PER Minute' should give a clue, but it is much easier to just look for a canned no-thought approach.

Oh, no matter how you calculate it, don't use a timer for your time base, either use the rolling timestamp from the counter module (which of course, you neglected to specify what one it is), or use a cyclic interrupt in your program (again, not knowing anything about the hardware, there is no point giving examples).


Go ahead, and -1000 to me, I really don't care.

 

[Phrog30]

+1 to Russ.

Go ahead, and -1000 to me, I really don't care.

Really, if you don't care then why post? You and RussB are both idiots.

Go ahead and reply to my comment, I really don't care!!

Have a nice day!!

James

 

[wimpiesplc]

Go ahead and reply to my comment, I really don't care!!

Really, if you don't care then why post?

idiot.

 

[daba]

I, for one, do not like to see personal insults being hurled around at people for making statements that you may not agree with.

Each and everyone of us is entitled to voice an opinion, and you are equally entitled to agree or disagree with those opinions, but abusing another person in the process is not on.

Gentlemen/Ladies, I would prefer that you all behave in a "professional" manner.

 

[Robobob]

+1 daba