photoelectric sensors light on / dark on

Join Date
May 2010
Location
London
Posts
689
In short, I have inherited a project that has been abandoned by the original installers. Yes abandoned before it has been finished. They realized they couldn't program it to work properly and have used incorrect sensors among many other things.

The system is fairly simple in that it is 5 conveyors end to end (about 4M long each) that takes mattress bases into a wrapping machine.

The workers have stations along the belts making the bases and when they are finished, they throw them onto the belt and these are automatically queued and taken into the wrapping machine.

The original program did not work at all so I wiped it and started again. It is now a beautifully running system apart from one thing.........

There are 11 photoelectric sensors along one side of the belts to detect mattress bases. These work fine when the bases are of a light colour but when they are dark ie brown or black - they do not see them at all.

The sensors that are on are set to full range but to no avail with dark colours.
I suggested fitting reflectors so that the bases break a beam, but they are not happy with that as they would impede the workers putting the heavy bases on the belts.

So now I am trying to find photoelectric sensors that will see both light and dark.
My thinking process was that I could probably double up the sensors - The originals for light colour as they are now and new ones for dark colours. but I don't want to order 11 sensors if they don't work the way I expect.

Oh and the original sensors are the 'barrel' type and there would be just room to drill another 20mm hole for the extra ones.

Any suggestions from anyone experienced in this?
 
Should have mentioned the distance: when a mattress base is on the conveyor it is no more than 1M from the sensor.

Ultrasonic would probably do it but the expense would not. $1000 a sensor is too much.
 
Have you contacted Omron or Sick to help you with your problem?
They probably have the solution with only one sensor. You can probably borrow one sensor for testing.
 
Didn´t you mention in your 1st post that the client didn´t like the idea of using reflectors??
 
Ronnie,

Would an analog sensor work? or would that mean too much wiring?

I would talk to Pepperl & Fuchs in the UK as they have always helped me in the past with photosensors/capacitive sensors for sensing bags/bins etc.

P&F do square sensors that could look up through the conveyor inbetween the rollers - Type CJ15 (up to 15mm) or CJ40 (up to 40mm)
 
The conveyors are like solid rubber coated belting - so no looking up from below.

And yes, they don't want reflectors so not sure if the proxy I have chosen would work without one.

Above placed sensors would not work as these bases are big and they throw them on high endways sometimes - not to mention the gantry to build for 11 sensors
 
Call the experts!
There are probably more than enough vendors in your area that would love your $$$'s enough to send people in to look at your problem and solve it for you by selecting the appropriate sensor.
I would start with your most used vendor and have them call in a Banner/Turck/Sick/IFM rep to find the solution for you.
Why re-invent the wheel when there are people that already have the solution to your problem?
 
Try using IFM effector with longer range sensing. The general application or the specific application sensing. Specific sensing types can even sense a transparent object.
 
This is 2015! There is literally 1000's of sensors that will work in this application. My preference would be laser which can be had for $250 each. If you want to be cheaper, there is still lots of photoelectrics that will work just fine. Call a rep from a good company.

Sick
Keyence
Panasonic
Etc.
 

Similar Topics

I am using a few Efector OJ 5036 Laser Sensors. I was using reflective tape but does not seem consistent enough. Does anyone know of any long...
Replies
2
Views
1,650
Hello all, I am looking for some low-cost photoelectric sensors capable of a sensing range of 20ft. The application is indoors, so they do not...
Replies
6
Views
3,705
Hey, I am entirely new to PLC's and am trying to help my friend with a project. He wants to take the signal from a PNP photoelectric sensor as...
Replies
12
Views
2,184
Hey everyone, We are trying to attach a photoelectric sensor to a conveyor to count the number of parts produced in a plant. However, there is no...
Replies
5
Views
2,160
Can noise (electrical noise) affects a photoelectric sensor? We have encountered a case wherein the signal "chatters", but when wire was replaced...
Replies
4
Views
1,678
Back
Top Bottom