PickMaster Start/Stop sequence misspick problem

Hello,

I have a problem with Start/Stop sequence in PickMaster program.

Machine has got two IRB360 robots and each of them has it's own conveyor for picking.

I use Start/Stop bits in PickMaster to start or stop conveyors - send bits via Profinet to PLC.

I have to use small pick areas, because there is a risk of collision between robots, so their areas are limited.

Below i described my problem:

If there is too much items on the conveyor pick area for robot, then PickMaster reset start bit and stop the conveyor. The problem is, that sometimes conveyor stops and starts few times in short time by PickMaster. This cause, that robots can't pick the item - miss pick position (error +/- in conveyor X-axis). Robots starts make good picks after missed 3-5 items (probably number of items in it's last queue/area) only if conveyor doesn't stop again in short time.

How can I solve this problem? Should I write some additional functions in RAPID program or this problem is not possible to resolve? If not, the only way is to not stops conveyors, but slow them down?

Thank you for answers.

Yes. The sequence looks like below:

1) Robot picks items from moving conveyor.

2) Too much items on picking area - reset start conveyor bit in PickMaster ConveyorWork Area settings. Conveyor stopps

3) Robot picking items from stopped conveyor.

4) Starting conveyor

5) Robot missing picking few next items from running conveyors (small pick error) - robot moves to picktarget but misses it

6) Stopping conveyor

7) Starting conveyor. Picking error increases

Yes, I use DSQC2000 Q-Track module, where I have connected two encoders (one for one conveyor). I use also PickMaster RAPID program without adding more conveyor tracking functions.

No. Each robot use it's own conveyor work area in normal work. One robot - one conveyor - one conveyor work area. Resetting start bits, stops only this one conveyor.

The space between items are big enough - 8cm