PENN (Customer) asked a question.
Hi all,
I have a ladder routing that pretty well senses (x001) 5 drops of a pneumatic arm and then advances the conveyor until the arm is moving back up. It all works fine except the machine seems to be slower at dropping intermittently throughout the cycle. Not sure why... don't have access to it's logic. Regardless, the conveyor typically moves for 500ms except when the arm is delayed. Then the conveyor might move 750ms. The problem is the gap on the conveyor between the drops.
Basically, I want to move the conveyor a static distance every time. Best way I would think is to have a 2nd sensor (x003) that stops the conveyor. Honestly, I'm new to this so struggling how to control that flow of 5 drops (x001) -> advance conveyor until material is sensed by X003 and stop it. That part is easy enough but not sure how I restart the conveyor if condition of X003 is still signalling to stop conveyor.
This is the routing from my previous implementation with 1 sensor.
Any help is appreciated.
RP
Could you not just have a timer that runs for 500ms when the counter has reached 5? That should make the conveyor move the same distance each time
Now that I think about it, the problem with a timer is that if I slow down the machine the conveyor travel will be too long between intervals. To accommodate I would have to slow down the conveyor. Very doable but I think a second sensor would be better.
I tried that and couldn't get it to work consistently. Probably How I coded it. Logically that would make the most sense.
If I am understanding you correctly, after prox X1 counts 5 times you want to index the conveyor until prox X3 sees material while ignoring X3 when starting the conveyor? Assuming there will be a point where X3 will go low in the process, this should do the trick.
Thanks for your reply. I think I follow what you are doing. I will have to try it and advise.
Greatly appreciated.
RP
Thanks, that seems to do the trick. I haven't tested it on the plc yet but recreated it with Do-More simulator and seems to do as expected.
You help is appreciated.
RP