Distance sensor for diameter compensation
Distance sensor for diameter compensation
(OP)
We have in operation one re-spooler machine to wind welding mig wire on 15 kg plastic spools
The machine consists on a un-winder, a dancer unit and a winder
As the unwinder gives wire to the winder the diameter of the wire coil decrease. To compensate the diameter reduction there is installed a sensor (see picture attached)
The sensor is very old and it was custom made for it. I am not sure what kind of sensor is, but I am guessing is an ultrasonic sensor
The signal from the sensor is unstable (it varies +/- 1V ) while the coil is spinning and this is making the speed syncronism between winder and unwinder to become unstable too
My first thought was that the problem was a signal interference through the cables so I made a few measurements and the signal is coming unstable from the sensor it self
Is an ultrasonic distance sensor good for this application?
Is there another type of sensor that will not be affected by the spin of the wire coil?
Any help will be apreciated
The machine consists on a un-winder, a dancer unit and a winder
As the unwinder gives wire to the winder the diameter of the wire coil decrease. To compensate the diameter reduction there is installed a sensor (see picture attached)
The sensor is very old and it was custom made for it. I am not sure what kind of sensor is, but I am guessing is an ultrasonic sensor
The signal from the sensor is unstable (it varies +/- 1V ) while the coil is spinning and this is making the speed syncronism between winder and unwinder to become unstable too
My first thought was that the problem was a signal interference through the cables so I made a few measurements and the signal is coming unstable from the sensor it self
Is an ultrasonic distance sensor good for this application?
Is there another type of sensor that will not be affected by the spin of the wire coil?
Any help will be apreciated





RE: Distance sensor for diameter compensation
If your spooling process takes long time in comparison to the drum speed, you should be able to filter out the variations with a simple first order lowpas. I would try a 10 k resistor and a 100 uF capcitor. You may need to experiment with other time constants or something else if your signal is a 4-20 mA. But still - a low pass filter usually works qute well.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Distance sensor for diameter compensation
I will buy those components and make a Low Pass Filter and see what happends
RE: Distance sensor for diameter compensation
Walt
RE: Distance sensor for diameter compensation
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Distance sensor for diameter compensation
My apology!
Walt
RE: Distance sensor for diameter compensation
RE: Distance sensor for diameter compensation
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Distance sensor for diameter compensation
The filter will stabilize those signals?
RE: Distance sensor for diameter compensation
The filter removes fast variations that the uneven coil surface causes. Nothing else.
It is very easy to find out if the sensor works correctly. Direct it towards a smooth surface and measure output as a function of distance. If the sensor is healthy, you will get a linear characteristic.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Distance sensor for diameter compensation
RE: Distance sensor for diameter compensation
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Distance sensor for diameter compensation
RE: Distance sensor for diameter compensation
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Distance sensor for diameter compensation
RE: Distance sensor for diameter compensation
Keith Cress
kcress - http://www.flaminsystems.com
RE: Distance sensor for diameter compensation
Was AFK for a while.
A 100 uF capacitor is almost certainly an electrolytic one. Make sure that you get the polarity right.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Distance sensor for diameter compensation
I put an empty reel. Made the unwinder spin. The output of the sensor stays on same value. No more unestable reading
I could not try the low pass filter yet because we just run out of wire. We will receive it next week
The components I have to build the filter are:
resistor: 10k ohm - 1/4 watt
capacitor: 100uF - 25 V
picture attached
RE: Distance sensor for diameter compensation
Keith Cress
kcress - http://www.flaminsystems.com
RE: Distance sensor for diameter compensation
Full reel: 2 V
Empty reel: 7,2 V
RE: Distance sensor for diameter compensation
Those values are still a great place to start and likely will do the trick for you.
Let us know how it works out!
Keith Cress
kcress - http://www.flaminsystems.com
RE: Distance sensor for diameter compensation
The resistance and capacitance values mentioned above result in a 1 second time constant, so you need to be careful about whether the time constant is compatible with the timing of how the transition from one layer to the next is detected.
TTFN
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RE: Distance sensor for diameter compensation
Now the signal oscillation is +/- 0,3 V
Should I used a bigger cap? 150 uF? 200 uF?
Resistor used is 10k
Process speed performance has improved a lot!
RE: Distance sensor for diameter compensation
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Distance sensor for diameter compensation
RE: Distance sensor for diameter compensation
How did the problem start? Did it ever work well?
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: Distance sensor for diameter compensation
Did it ever work well?
I am not sure. It took me a lot of time to get the machine to work. Specially to calibrate the PID control. Now I think that 50% of the problem was the signal from the distance sensor. I did not notice back then