tough environment tail roll sensors

lesmar96

Lifetime Supporting Member
Join Date
May 2017
Location
PA
Posts
520
Good Morning,
I have a customer who would potentially like to install tail roll sensors on their conveyors in their quarries. The plc will monitor the conveyor for movement and will shut down conveyors accordingly if there is any problem.

Any one have a good recommendation for or experience with a prox sensor that will is built for a wet/dusty environment like a quarry?

Just checking around for options. Don't want to end up with something that gives us a lot of trouble. Thanks!
 
I don't know the cost. The EC provided them at the time and this was many years ago.
 
I know a proximity 120vac that can be mounted on the idler shaft. Problem with that is that a bolt needs to be mounted in center of shaft. Kind of hard to retrofit something like that in existing system. I know you can use a magnetic drill to drill it but it always seems like it comes out where its not completely centered.

http://catalog.jamiesonequipment.com/Asset/ElectroSensors_Catalog JEC.pdf
https://www.jpsdesign.com/Portfolios/Hubbell/SpeedSwitch.pdf

here is a couple of examples above that could be used off the shelf.
 
I would suggest not to place a sensor on the tail drum.
Tail drums often get adjusted to track belts and are usually the lowest point on the belt, where spillage builds up. You will regret it.
Put a floating caster wheel somewhere in the middle of the belt that has a flag on it and use a standard proxy. It will be much more reliable.
 
Just checking lesmar as this was not entirely clear to me from your question. Is your client looking into retrofitting on existing conveyors, or rather installing new conveyors with roll sensors installed?


On new conveyors we typically include something like what JesperMP describes. However this means we then use a slightly modified shaft for these new conveyors if our customer specs the option. Retrofits are not common for us. We use standard inductive sensors, either stainless or plastic as most of our products are used in dusty and corrosive environments. The pulse signal goes to a digital input on a PLC. The logic of counting pulses and raising warnings and alarms is done in the PLC.
 
Just checking lesmar as this was not entirely clear to me from your question. Is your client looking into retrofitting on existing conveyors, or rather installing new conveyors with roll sensors installed?


On new conveyors we typically include something like what JesperMP describes. However this means we then use a slightly modified shaft for these new conveyors if our customer specs the option. Retrofits are not common for us. We use standard inductive sensors, either stainless or plastic as most of our products are used in dusty and corrosive environments. The pulse signal goes to a digital input on a PLC. The logic of counting pulses and raising warnings and alarms is done in the PLC.


Thanks for asking. This is a retrofit and not a new install. We are looking into upgrading their controls from a simple start/stop setup to an automated process.
Your description is exactly what I was picturing. Use a prox to watch a key or some other target and use a high speed counter in the PLC and run logic from there.
 
When counting in the PLC rather than in a dedicated piece of hardware, you are either looking into special high speed inputs, or alternatively you make the hardware such that the pulses become longer.



We do the latter which allows us to use standard PLC inputs. We use plastic or nylon discs (I don't know the exact material) bolted to the conveyor shaft. Half of the circumference of the disc is covered with a stainless steel strip. The sensor detects presence of the strip for about half the rotation time, long enough to not miss a pulse. No ultimate precision but it is good enough for the purpose. Works for us.
 
When counting in the PLC rather than in a dedicated piece of hardware, you are either looking into special high speed inputs, or alternatively you make the hardware such that the pulses become longer.

We do the latter which allows us to use standard PLC inputs. We use plastic or nylon discs (I don't know the exact material) bolted to the conveyor shaft. Half of the circumference of the disc is covered with a stainless steel strip. The sensor detects presence of the strip for about half the rotation time, long enough to not miss a pulse. No ultimate precision but it is good enough for the purpose. Works for us.
We have two versions of the disc.
One for fast conveyors with the actuating steel insert in a half-moon - like the one you describe.
Another for slow conveyors with the many steel inserts over the circumference of the disc - similar to the pulser disc on page 7 of this PDF http://catalog.jamiesonequipment.com/Asset/ElectroSensors_Catalog JEC.pdf (from Jim3846's post).
For the relatively simple task of monitoring for a stuck belt, there is no need for special fast PLC inputs.
 

Similar Topics

Hi, I'm wondering how to program a function that has an integer(or word) input but return the value contains in the address of the input. for...
Replies
8
Views
3,998
Someone had posted a touch screen here a couple weeks back that looked to be real tough. It even took a shotgun blast. I can't seem to find that...
Replies
1
Views
1,564
Not sure why I'm having a tough time but all my logic seems to be right but its not working. I'm trying to get the LEN function to get a value...
Replies
0
Views
1,493
Dear guys, the FIFO is a pain for me. I am using siemens s7 to program it. When I use FC84 ATT table to store the data, it can work properly. But...
Replies
7
Views
4,479
Well... let's see what you can come up with... We have a hydraulic press. The hydraulic pressures contained in two accumulator systems close the...
Replies
58
Views
34,196
Back
Top Bottom