Allen Bradley PL5 issues

[kevbloke]

Good morning Gents
We have a filler for filling PET bottles with fizzy drinks.
Its getting old and drops a few bottles here and there which causes big jam ups and bends bits on the filler.
I am very good with Siemens Step7 but am new to PL5 software.
The bottles go in past a sensor which then puts a bit into a shift register, the bottle is then detected again as it leaves the filler and enters the capper which is then put into another shift register. Is there a function in the software with which i can monitor the shift register to spot if a bottle is suddenly missing from it when it leaves the filler to enter the capper? I can then use this to stop the machine.
Ive tried counting bottles in and out but by the time this has happened another 10 or so bottles have gone through still causing a jam up.

Many thanks

Kevin

 

[JesperMP]

Bottles goes in. Bottles goes out. If you trying to sense a jam by the difference in bottles going in and out, there will be a delay from the actual position of the jam to the output. That means there will be a certain number of bottles that can get in the jam before it is detected.
I think this is inherent with sensing the jam after the output. No way to program out of this problem.
As I see it you should consider adding some sensors to detect jams inside the filler.

I have no experience with filling or bottling machines. Maybe the best strategy is to avoid jams (maintenance ?) rather than detecting them when they happen.

 

[willxfmr]

Add a photo eye or some other type of sensor at the filler, and use the input bit from that sensor as half of a compare. The other half would be the bit in the shift register. Only fill the bottle if they match.

 

[kevbloke]

Cheers Gents

You have just backed up what i told management 2 days ago.
They do believe that the laptop is magic and can sort anything out. Bless

 

[GlenGineer]

Bsl

I have a conveyor system for a paint line that utilizes the bit shift left function to keep track of whether product is present. Product is detected with a photo eye then we flip a bit. 0000000000000001 is the result. The conveyor indexes and then we utilize the BSL function and get 0000000000000010. At one point its at the painting station say at 000000100000000. When that bit is on the paint gun is triggered. Eventually it gets to another photo eye. If I wanted to I could cause an alarm if it expects to see product because 0100000000000000 and yet the photoeye see nothing.

I've seen shampoo filling and capping machines. However I never have seen the programs. My guess as to how it operates is thus: Bottles go down a conveyor system. Your sensor detects the bottle. Based on this input the filling nozzle is extended and somehow captures the top of the bottle. The filling carousel indexes. Each time it indexes the BSL routine is actuated. At one point it extends the filling arm to place it back on the conveyor. Next comes the sensor for the capping machine where it follows a similar operation.

I now see what your problem probably is it knows exactly where the bottle is until it puts the bottle onto the conveyor. Then it looses track of the bottle until it hits the next sensor. If that's the case I would add a sensor at the point where its dropped off the filing machine.

Aren't there also combined filler/capper systems?

Hope this is of some value.

Glen