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Sunday, May 20, 2018
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Need a count/pulse per foot

I work for a manufacturing company and have just recently started working with the control systems, 3 years. I am a component level repair tech by trade, so control technology terms are new to me.
I'm learning along the way with 3 simple controls done so far.

This is my problem. I know is simple. but with all the research I've done, I still don't know exactly what I need.

We have a product printer on our QC line. along with the product data it prints the footage every foot on a flat product that can be up to 600 feet long, or longer. The encoder that comes with the printer is 300cpr using a 3 inch diameter wheel. It is approx' 1/8inch off for every foot. The print controller software is hard coded for inches with only 2 decimal points so I can't put in an accurate off set.

The printer will accept an outside pulse to trigger the printing so My goal is to get a better encoder and device that can be programmed to give us a pulse every one foot, or even every 3 to 5 feet.

Although this sounds pretty crazy, they want an accuracy of 1 foot in every 1K feet.

One more additional hurdle, the machine will be stopped and restarted often in the course of say 600 feet. From what I have read this could add a jitter issue.


By Mike Larkin on 11 July, 2016 - 2:12 pm

I just hope your machine is gear driven instead of chain driven. It is impossible to get any accuracy with the chain drive because of the slack.

By SteveMyres on 11 July, 2016 - 8:06 pm
1 out of 1 members thought this post was helpful...

Chain's fine if you have a support. Heck, it wouldn't even work right without the support. The catenary loosening and tightening all the time destroys the motion and puts a LOT of repetitive stress on all the components. No one competent would use a chain for positioning without supporting it. PLUS, if even that's not good enough, you can switch out the chain for timing belt (and yes, still support it).