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JD1ROSE

shaker

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I need some control circuit help. I have a shaker for scrap that is used on all of our press lines. I need to detect when the shaker stops for a malfunction. I want to hook up a prox sensor that is stationary and a bracket that will move with ths shaker in and out. So it will make and break the prox sensor. If this signal stops for more then 1 minute I want it to stop the press line with a e-stop fault.I need help to come up with the hardware to create the logic. If you can help me please E-mail me at, r1daros@hotmail.com Thanks, Roy.

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Hi From the Omron stable, a CPM1A will suffice. Pp

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Any Omron PLC could do this job. (or any other brand) You could also do this with a timer and the prox. You may want to consider shutting the press down with a "Top Stop" signal. Shutting down with e-stop may leave the press stuck at the bottom of the stroke. Hope this helps

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Let me second the Top Stop rather than E-Stop idea. If you ever have had to recover from a BDC stop on an Upset Press you'll never use E-Stop. I'd envision the following A simple Omron Prox to an input channel on any Omron PLC. Let the Normally Open of the input drive one timer and the Normally Closed of the input drive a second timer. Set both for 1 minute. That way no matter where the shakler stops, {on or off the prox} lack of motion will cause a timer to time out. Let the or of the timer then trigger your stop logic.

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In my experience with shakers, it is better to go with a diffuse reflective photoeye than a prox. Shakers tend to shake in the wrong direction sometimes, especially during starting and stopping. This can possibly cause the bracket to smash into the prox. Using a photoeye will allow you more space between the sensor and the bracket.

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Thanks for everyones help, I need to do it with one prox switche and timers. It will be set up to make and break sence. I need help in the logic. Roy..

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Take a swing at it an post what you come up with so we can start from there

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Must admit I would go with 2x timer relays (delay on and off) using their N/C outputs in series in a 'all hold' or stop feed line. Poss use mercury 'tilt' switches in this app? if prox or optical give problems? I've seen presses wrecked by lube monitors which only looked for the sensor to be on for 'good' (they were using only a delay off timer and if the sensor stayed on the timer never timed) therefore I always trap for a stuck ON sensor as well as a stuck off condition. As for shakers - anyone else have probs with the modern electrical ones? they dont seem to last anywhere near as long as the old ones (and I do check the current etc) - I've given up using electrical ones in powder plants etc and use the air type - dead simple and very reliable.

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Hello guys, Below is what i'm looking for, I need the wirering for it, if someone can draw it up and e-mail it to me. r1daros@hotmail.com Thanks Roy When the pulsing stops, you want to stop the line. So wire the output of your proxy to a 'Timer ON', which will time out when the proxy stays on for too long. Also wire the proxy inverted signal to another 'Timer ON'. You might use a fast relay to invert the signal. This timer will time out when the proxy stays off for too long. Use N/C contacts on the timer outputs in series to allow the line to run. For starting up, you will need to temporarily bridge the timer outputs until things are running.

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