Ultrasonic sensor to measure material roll diameter

Will ultrasonic sensor work for measuring roll diameter in Winder/Unwinder application? Material: paper, plastic films, foil. What is the loss echo feature on some sensors? Please, share your experience.
Thank you.

PaulB.

How thick is the material and what is resolution on the sensor?
Also, is this to be measured while winding?
What accuracy do you need?

My experiance is mainly for tank level measurement, where ultrasonics are generally acceptable. I have never used ultrasonics for anything that requires resolution better than 10mm.

We use them for brake/tension control on the back of a winder and they do a great job. They control an I to p that adjust the pressure on a disk brake setup. We are not looking for a vast amount of span so they are sufficiant. I am not sure what you are trying to use them for. maybe a little more info and I can help more.

Check out this thread and see if it is what you are looking for:

http://www.plctalk.net/qanda/showthread.php?t=16927&highlight=Uncoiler

As for the "Loss of Echo" feature on sensors, we use Hyde Park and depending on the model you can choose what happens when you loose the echo, ie. no signal return from the object which you are trying to detect. You can set the sensor to go to minimum value on loss of echo, or maximum, or analog value can hold until signal has been re-established.

PLCS.net RULES!:site: Only 11 and 1/2 more hours till beer!

Currently we are using analog(0-10V) ultrasonic sensor by Baumer Electric, UNDK30U6103. It is measuring diameter during winding. Data sheet of the sensor is stating that resolution of the sensor is less than 0.3mm. It is more than enough in our application. We are using it for brake/tension control. Some of our customers complaining that during winding signal from sensor is droped intermittenly.
I am wondered is it because faulty sensor or cheap sensor? Or this is typical for ultrasonic sensors and needs to be handled in the software (preserve "old" signal for couple seconds if input from sensor is lost).
Also what advantage/disadvantage of using prox switch and tooth gear and calculating roll diameter from the web speed and pulses per revolution instead of measuring it?

One of the disadvantages of calculating diameter is when a new roll is put in what diameter do you use ? I've used a combination of ultrasonic for when the machine is stopped, then calculation when running.

We have been using prox switches for years to measure roll diameter. They work great. The one disadvantage as SimonGoldsworthy stated, the new roll diameter. For unwind applications we look at are corehold interlock to reset the diameter. And for rewind applications we look at the drive itself. If its turned off we assume the diameter to be zero or core diameter.

Another disadvantge is if the roll in out of round some averaging will have to be done.

We have used ultrasonics before, they worked but, I wasn't very impressed. I just completed a special unit that used a Magpower system.

The ultrasonic are just to shaky for me

You might want to check out this sensor
http://www.baneng.com/products/measure_inspect/lg5lg10/

I have never used the Analog model but I use the Q50 laser line to measure poly remaining on the core and it will measure it down to about 5 wraps left