Motion Verification Detector

Take a look at hall effect sensors, or optical encoders.

Try "stopped motion sensor", e.g. this one.

Thanks John, great frequency range but the response time is longer than my inspection.

Do you want to MEASURE the speed or distance traveled? If so, and you don't want a PLC, you would use what's called a "Programmable Limit Switch" (PLS).

http://amci.com/standalone.asp

If all you want is confirmation that it moved or is moving, you would use a "Speed Switch".

This is an intermittent motion -- it applies tape to a box/package passing through the machine -- correct?

If so, then you need to integrate at least two sensors.
1) Box/package enters tape station.
2) Tape is applied.

This is my reasoning: If only the tape dispenser is monitored, but the dispenser turns only intermittently, how do you know when it is supposed to be turning? (How do you specify an alarm condition?)

If you sense when a box enters the tape station, you can use that action to set the alarm condition for the tape dispenser (i.e., If tape doesn't dispense within X seconds after box is detected, then alarm.)

If this is a typical corrugated cardboard box, another option may be to verify if the box flaps are actually taped closed as it exits the machine.

If I'm picturing the scenario correctly, let me know.

By the way, I have a client who makes a machine that applies glue to joints. We had to make sure the glue was there so we had a luminescent marker material added to the glue* and used a luminescence sensor from Sick Sensors to look for it under UV light. We got the idea from a packaging tape machine at a trade show. Worked perfect.

*(apparently this is very common in the glue industry, yours may have it without even asking)

Hey J,

Yes, that is a good idea too. I considered UV sensors. Actually my visible light sensor from Keyence does a pretty good job but the tape reflectivity varies a lot so I would end up getting random pulses of random duty cycles.

Now I'm looking at placing a reflective surface just below the knurled surface of the roller that is in direct contact with the adhesive. Then with one photo-eye to detect a box, I'll watch that roller for pulses. And since custom circuits are discouraged here, I'll use a PLC to monitor both photo-eyes, placed so as to provide signals at the same time.

You need to be careful just what you are detecting: If the tape roller moves but the tape runs out, your process may just keep on running with an unwrapped package.

If he senses motion on the tape storage reel, not the dispenser drive roller, when the tape runs out the tape linkage between the two reels is broken and the alarm will be triggered.