SHAKER 1

[jd1rose]

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.

Thanks,
Roy.

 

[RalphChristie]

Can you be a bit more descriptive regarding the shaker and the system? Voltage level, single or three phase, PLC-based or not, etc. etc.

Regards
Ralph

[red]Failure seldom stops us, it is the fear for failure that stops us - Jack Lemmon[/red]

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[DaveScott]

I assume you have checked that the proxy is fast enough to switch on and off at the speed of the vibrating feeder?

If it is OK, then you will have a signal that is pulsing.
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.

 

[LionelHutz]

If you have the prox switch set-up to produce a pulsing output then you can get a module that is for use with a proximity switch. The prox switch is likely a NPN transistor output so use something like a Phoenix Contact MCR-f/UI-DC Universal Frequency Module to interface to it. I don't seem to be able to link to the product but use

http://www.phoenixcon.com

and look for it under the signal conditioning - isolators and converters section. Of course, there are other companies that make similar products but I only know of this one. It should give you an idea of what you want though.

If you have a PLC then investigate if you can feed the switch signal into a counter or high speed input on the PLC.

 

[jraef]

I would just use an acceleraometer or another type of vibration transducer and get an analog output from it proportional to the movement. Then you can design your own thresholds to determine minimum functionality as well as EXCESSIVE vibration, as in a broken component.

Something like these.
Bentley Nevada link

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[jd1rose]

Thanks for your help guys.

What I need is the hardware set up and wirering. The prox switch will come on and go off to detect movment. When it stops going off and on for more than a minute or so. Need it to top stop a press. It can be set up for 24 vdc or 120 vac.
The simplest way posible.

 

[mc5w]

Telemecanique also makes a motion sensing inductive proximity switch that would sense say a large bolt that is screwed into a shaft. This will cut off when the shaft stops. This is similar enough to your application to work. All of the timing relays and logic that you need are built into it and about the only relay you would need is an ice cube relay that is interposed between the prox switch and the e-stop wiring.

I am pretty sure that some other people make a motion sensing proximity switch that shuts off when the sensed object drops below a certain speed. On some of the punch presses at work there was an electronics package that was connected to some type of inductive sensor but the Telemecanique package gets rid of the need for shielded audio cable and an external electronics package.

One typical application for this kind of proximity switch is at the opposite end of a conveyor belt from the motor and gearbox. In this case the prox xwitch senses belt jamming or slipping and stops the motor before the live sheave grinds through the belt.

Mike Cole

 

[jd1rose]

Dave Scott, the way you described is the way I'm looking to do it. I'm have a little trouble drawing up the logic. Could you or someone FAX me over a fax with the drawing for how I would wire it up as you described above.
Thanks,

ATT: Roy DA Rosa

Fax Number 1-562-941-4967

 

[DaveScott]

Roy DA Rosa,
See the following link for a rough sketch.
shaker stop detection circuit