Iangwf
Member
Hi
Background information
I am currently in the process of putting together some logic / ideas for a machine modification at my place of work. (1756-L73S Controller)
The machine has a conveyor (main) running through the middle at about (1) revolution every 10 minuets,
throughout the day this conveyor may speed may change.
There is also another conveyor (pusher) that pushes product onto the main conveyor, this is currently operating and pushing every 30 seconds or so.
Both conveyors are controller by VSDs and are programmed into the original PLC code and currently running fine.
Challenge
I need to make the speed of the pusher conveyor follow the speed of the main conveyor as this varies throughout the day.
Code
I was thinking using a prox on an intermediate gearbox shaft to count pulses of about 50 per rotation of this shaft. (1000mm belt travel = about 600 pulses)
I was considering counting pulses for 20 seconds then storing the value in some type of memory location, then repeating the count for another 20 seconds and storing this vale. I am not sure what type of memory / function to use.
Then I could compare the (2) vales and come up with a deviation if the main conveyor speed changes.
This deviation value could then be used to modify the speed of the pusher conveyor if the main conveyor speed changes.
Does this seem like a reasonable approach or have I got it all wrong.
This is a very basic concept and does not need to be precise, as it is not super important to make this extremely accurate.
Please try to dumb down your solution as I am extremely green at PLC programming. (as you can probably tell)
Thanks
Iangwf
Background information
I am currently in the process of putting together some logic / ideas for a machine modification at my place of work. (1756-L73S Controller)
The machine has a conveyor (main) running through the middle at about (1) revolution every 10 minuets,
throughout the day this conveyor may speed may change.
There is also another conveyor (pusher) that pushes product onto the main conveyor, this is currently operating and pushing every 30 seconds or so.
Both conveyors are controller by VSDs and are programmed into the original PLC code and currently running fine.
Challenge
I need to make the speed of the pusher conveyor follow the speed of the main conveyor as this varies throughout the day.
Code
I was thinking using a prox on an intermediate gearbox shaft to count pulses of about 50 per rotation of this shaft. (1000mm belt travel = about 600 pulses)
I was considering counting pulses for 20 seconds then storing the value in some type of memory location, then repeating the count for another 20 seconds and storing this vale. I am not sure what type of memory / function to use.
Then I could compare the (2) vales and come up with a deviation if the main conveyor speed changes.
This deviation value could then be used to modify the speed of the pusher conveyor if the main conveyor speed changes.
Does this seem like a reasonable approach or have I got it all wrong.
This is a very basic concept and does not need to be precise, as it is not super important to make this extremely accurate.
Please try to dumb down your solution as I am extremely green at PLC programming. (as you can probably tell)
Thanks
Iangwf