Servo Electronic gearing

[zed]

Here is an application in which I'm unsure I will be able to do with unistream.  Its a servo smart belt infeed.  3 short conveyor belts in series receive incoming products and index them to the proper position for a downstream cartoner machine's flighted infeed conveyor.  The three belts need to match the speed of the cartoner which i would do by mounting an encoder to the downstream cartoner and feeding that signal to the a high speed quadrature input on the unistream.  The three conveyor servos would be e-geared to this "master" axis.  From there when a product is detected on the first belt by a photo eye its position is compared to the master and a corrective relative move (advance or retard) is superimposed on the current velocity.  The second and third conveyors repeat the process to achieve the required position with increasing precision.

I would use the new ecat module and third party servo drives and stainless washdown servo motors.

Do you think this is feasible and if so how would you configure the egear to the encoder?

 

Thanks

 

 

[Joe Tauser]

8 hours ago, zed said:

Do you think this is feasible

Yes*.

You're describing a self-tuning multiple velocity variable drive system.  You're going to have to make this thing dance.

You'll need a photoeye on every conveyor, and know the exact distance between each photoeye to tweak the belt speeds until all the relative velocities match. 

We did a simpler flighted belt system moving extruded doughball patterns at a bakery.   We had to sense the actual flights as well and use them as a virtual encoder for the transport belt to time the transport belt and the delivery belt together.

BTW, we were told the flights were evenly spaced but they were not.  So we had to que and shift the flight positions and adjust the belt speed a bit based on which flight we were interfacing with at the time.

 

Joe T.   

 

[zed]

Thanks Joe.  In this case all three conveyors would be egeared to the virtual master axis except when making a position adjustment.  Yes PE's for each conveyor.   I don't need the distance between PE's as the position adjustments are all independent and within a cycle.  The master axis would provide the cycle repeat (12" pitch) by either a z/z' output on the encoder or a prox detecting downstream flights.  So how would one set this up?  I don't see an egear feature in the motion tools and i'm not sure how to set the encoder up as a virtual axis.  Maybe this is more of a software question and i've posted in the wrong spot?

Some examples https://www.nerconconveyors.com/Nercon/Conveyor/Conveyor-Equipment/Diverters-Mergers/Servo-Technology.htm