emptying unwinder sensor 1

[lukin1977]

The machine is an horizontal spooler used to unwind reels full of Mig welding wire
I want to install some kind of warning devise that signals once a reel full of wire if almost empty
I am planning to use an already installed distance sensor that sends a 0-10V to the unwinder´s motor controller for speed compensation due to the fact the diameter decreases

The signals for the distance sensor are:

Full reel: 2 V
Empty reel: 6,75 V

I was thinking on a relay the switches ON at 6V.
Any helpful ideas will be appreciated

 

[jraef]

That sounds good to me, although I would likely use a "smart" relay so that I could program a WARN level at maybe 5.75V to operate one output, then an ALARM level at 6 to operate another one. Take them to a Stack Light, set up as Green means good to go, Amber means Warn, Red means Alarm and if it goes all the way to Empty with nobody paying attention to the Warn and Alarm, fire off the buzzer.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[lukin1977]

please tell me more about the "smart relay"?
Can I buy one or what?

 

[jraef]

Yes. They are also sometimes referred to as sub-micro PLCs. Typically at least 4 inputs, 4 outputs, sometimes one or more analog I/O, simple block programming.

Here's one, the Allen Bradley Micro810 (full disclosure, I work for them, different division, but it's a product I know).
If you get the version that has 24VDC inputs, it comes with 4 relay outputs and 8 digital inputs, but 4 of them can be converted to 0-10VDC analog inputs in programming. So you would take your analog signal from the sensor into one of those and once the unit has it, you can program the outputs to trigger off of the values. Programming can be done on the front plate, or on a PC with free software. You can usually buy one for under US$100.

There are dozens of other suppliers such as Siemens (who originated the idea), Moeller, Mitsubishi, Schneider, Teco, LG, the list goes on and on, and many of them brand-label products from each another. Many do not come with the ability to accept an analog input however, unless you add another accessory to it, which increases the size and cost.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[lukin1977]

That is right!. In fact I have installed one in this machine 2 years ago
Siemens Logo. So to do what I want I need to add the analog module for it

thanks

 

[Skogsgurra]

Better use one with AI in the standard unit. The 24 V units have that. Perhaps also the AC types nowadays.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[OperaHouse]

If you have a little electronic nouse, this would be an easy build with a three lead TL431, a 200K pot, and a small relay. Basically this chip is an op amp and a 2.5V reference. It will easily drive a small 50ma or less coil of a relay. Just adjust the pot to energize relay at any sense voltage higher than 2.5V. Use an extra one or two to drive a warning LED. You can buy 100 of these shipped for $2.

 

[lukin1977]

OperaHouse: Could you post a drawing of the circuit you are proposing?

 

[Skogsgurra]

For an industrial application?
April 1st was one month ago...

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[OperaHouse]

I submitted an April Fools post a couple years ago. Evidently it was too realistic and it was almost immediately deleted.


Strangely enough, ebay doesn't have any simple voltage monitor boards under $10. Here is the how to picture. Just want to remind people how easy it is to make a relay driver with this chip.

It looks like maybe I can't upload two pictures. If one only shows up this is a plasma pipe cutter I updated for a union welding school. It was donated to one school and they and the factory couldn't get it to work. It was a one of a kind R&D model that never made it into production. My friend got it for his union school and I was donated. I like welders We made a massive pipe cutter that will do up to a 30 inch pipe about 40 feet long. The frame weighs about 5 tons. We also did an 8 by 8 foot CNC plasma cutting table. Some weld shops don't have a problem building things.

 

[OperaHouse]

Here is the schematic.

 

[itsmoked]

Hey Opera; We're done with needing to link pics over to E...com. You can directly stick your pic in the posts now with the picture-with-a-little-circle icon.

Keith Cress
kcress -

http://www.flaminsystems.com