JRoss
Lifetime Supporting Member
I'm looking for more process oriented advice, but for those who care I'm using an AB ControlLogix L3 processor and Kinetix 6500 servos.
My application is a metering system for feeding stacks of product into a wrapper. I have to line the product up with the lugs on the flighted conveyor of the wrapper, so we're using servos to do this. This system is using six servo driven conveyors in series. The final one in the sequence is speed-matched to the wrapper, and the other five are used to gradually meter the product so that the spacing matches the flights on the wrapper.
My plan is to build on a similar system that I've done which only had a single servo following an encoder directly mounted to the flighted conveyor. In that case, I used the encoder as a master axis and "geared" the servo to it starting with a 1:1 gearing ratio. Then each time the product made a metering eye on the downstream end of the metering conveyor, I would calculate the lead/lag and adjust the gearing ratio up or down to compensate for error. The first couple of products would invariably be off, but product would quickly be adjusted to the correct position.
This system needs multiple servos because we are dealing with stacked product instead of single product, so I can't adjust things very fast, or product will go flying. But I can't wrap my head around the order that things should be chained together. Should I slave Stage 5 to Stage 6 (final conveyor), Stage 4 to Stage 5 and on back the line? Should I slave all the stages to Stage 6? Should I do something else entirely? Any advice would be much appreciated.
My application is a metering system for feeding stacks of product into a wrapper. I have to line the product up with the lugs on the flighted conveyor of the wrapper, so we're using servos to do this. This system is using six servo driven conveyors in series. The final one in the sequence is speed-matched to the wrapper, and the other five are used to gradually meter the product so that the spacing matches the flights on the wrapper.
My plan is to build on a similar system that I've done which only had a single servo following an encoder directly mounted to the flighted conveyor. In that case, I used the encoder as a master axis and "geared" the servo to it starting with a 1:1 gearing ratio. Then each time the product made a metering eye on the downstream end of the metering conveyor, I would calculate the lead/lag and adjust the gearing ratio up or down to compensate for error. The first couple of products would invariably be off, but product would quickly be adjusted to the correct position.
This system needs multiple servos because we are dealing with stacked product instead of single product, so I can't adjust things very fast, or product will go flying. But I can't wrap my head around the order that things should be chained together. Should I slave Stage 5 to Stage 6 (final conveyor), Stage 4 to Stage 5 and on back the line? Should I slave all the stages to Stage 6? Should I do something else entirely? Any advice would be much appreciated.