Kinetix 6500 Acceleration with MAG instruction

[lftmx3]

A line in our plant has always had an issue where everytime the jar filler stops/restarts, it wastes 5-8 bottles because of underfills. FWIW, the product is Mayonnaise. The machine uses Kinetix 6500's to control all associated motors. The rotating turret with the fill spouts is the master drive/motor. The product is pumped into the turret spouts with another drive that is geared to the master.

I haven't attempted tried yet, but I do have some ideas. Could the gear ratio in the MAG instruction be ramped down on the fly, with machine moving? Or can that value only be changed at stop? I could be thinking of this wrong, but my thought is starting the machine with that value at say 1.3, then gradually decreasing it down to the normal running value of .8 would allow the first few bottles to fill faster. Is this possible?

 

[joseph_e2]

I found this tech note (access level: TechConnect):
https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/56636/loc/en_US#__highlight


It says that the MAG instruction needs to be re-executed to change the ratio. They recommend stopping the axis with MAS to reduce strain on the mechanical components. I'd guess you could make small changes at a time and try it. I've never done it, though.

 

[lftmx3]

I found this tech note (access level: TechConnect):
https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/56636/loc/en_US#__highlight


It says that the MAG instruction needs to be re-executed to change the ratio. They recommend stopping the axis with MAS to reduce strain on the mechanical components. I'd guess you could make small changes at a time and try it. I've never done it, though.

Well there goes that idea, then! Thanks for finding that!

 

[joseph_e2]

It may work to repeat the MAG instruction while it's moving. The tech note implied that it would work but that if the ratio change was too big it would strain your mechanical components. It's probably worth a shot, even if you end up re-issuing the MAG instruction several times to ramp up the ratio. Like I said, I've never used gearing so I don't know for sure how to make it work reliably.

 

[kamenges]

We have used K6500 drives in winding applications on occasion. We change the gear ratio on the fly as part of unwind and rewind spindle control. It is what you need to do if you want to gear the spindle axes to the other axes and still account for the changing diameter.

Another thing to keep in mind is the MAG instruction is leading edge triggered so the instruction needs to see a false to true transition to initiate the action. The instruction uses the state of the input logic relative to the state of the instruction .EN bit to determine a false to true transition case. This infers that the MAG can only be updated once every other routine scan UNLESS you unlatch the .EN bit as part of the MAG rung. This lets you update the instruction every scan.

Keith

 

[Peter Nachtwey]

It says that the MAG instruction needs to be re-executed to change the ratio. They recommend stopping the axis with MAS to reduce strain on the mechanical components. I'd guess you could make small changes at a time and try it. I've never done it, though.

What? No ability the ramp from one gear ratio to another smoothly and predictably?