down bottle ejection

[controls2012]

I was hoping to get a little insight on adding an encoder to an already existing down bottle ejection from conveyor system. I am using a Banner MA4G Logic module and a MA5 delay module. The problem is the swings in conveyor speeds are a little to great, and what is need is a delay based from conveyor speeds. I hopped someone would have some ideas for a modification such as a encoder add on to this existing system.

The set up is three photo eyes two are aimed toward the shoulder of bottle and one down low. when only the one lower PE is blocked and neither one of the two upper PE's we will get a burst of air to eject the bottle, only adjustable with the fixed delay from the MA5 Delay module. Any Ideas on using maybe an encoder to time the delay with the conveyor speeds would be greatly appreciated.

 

[controlsdude]

Encoder selection
First
Select an encoder that puts out pulses that is about quarter the length of the bottle diameter. If you think you need better resolution then go for more pulses.
This would be a Pulse indiction.
inch = one pulse example
Second
Do calculation see if your digital input card with scan time can handle this encoder input. If not then use a high speed counter module or input. Most plcs have this feature eith onboard the PLC or as a specialty card. Sometimes even using a time interupt program or event driven program for this party is necessary.
Third
Select a photo eye arrangement to start tracking then with your beginning photoeye, put each bottle into tracking. A little downstream another photo eye arrangement to detect the down bottle. last photo eye to detect when to push off or divert the down bottles.

Typical Programming
Make a file that is long enough with the selected resolution above for this area on the conveyor bottle reject area.
Most tracking areas can be detected by putting a detected object on conveyor. run a counter at beginning pe, end at reject pe, with the encoder pulse one shoting the count.
Next
Each bottle has a rejection flag that is tracked with the file downstream. Shift a integer and set a number in the file for reject. If not rejected then the number is zero or some other number.
Just to be sure its detecting your bottles standing up you could put a number into tracking saying this is a standing bottle.
Then either count the bottle going by or take a snapshot of the file as it goes by by copying the file into another file for a one scan.

At reject area look for the reject flag number and push the bottle off the coveyor.

Of course all this is an indirect address in this file. Got any questions just write back.