I am writing a program to speed up or slow down a packaging machine depending on the weight of product in the container. This machine can run at 42ppm. I am using a SLC 5/03 with a Hardy Waver Saver card, Hardy load cell and an AB Flex 40 drive.
The machine starts out in manual mode (The PLC does not control in this mode) during this time the operator adjusts the volume and the mixture until the container is full and the weight is close to the target (Operator enters this number). At this time the operator will switch the machine into Auto mode.
Inputs:
0-10 VDC from pot to control machine speed in manual mode.
4-20 mA from drive as speed ref.
Analog value from load cell
Target weight (operator enter this)
I am using the above inputs to adjust the machine speed based on this ratio:
(Actual Value from load cell/Target weight) *Speed ref. = New machine speed
This New Machine speed then replaces the Speed ref. in the above equation.
I have read the some of the other threads on PID and it sounds like this may be an application for it.
Any advice or suggestions are welcome
Thanks,
Bob
The machine starts out in manual mode (The PLC does not control in this mode) during this time the operator adjusts the volume and the mixture until the container is full and the weight is close to the target (Operator enters this number). At this time the operator will switch the machine into Auto mode.
Inputs:
0-10 VDC from pot to control machine speed in manual mode.
4-20 mA from drive as speed ref.
Analog value from load cell
Target weight (operator enter this)
I am using the above inputs to adjust the machine speed based on this ratio:
(Actual Value from load cell/Target weight) *Speed ref. = New machine speed
This New Machine speed then replaces the Speed ref. in the above equation.
I have read the some of the other threads on PID and it sounds like this may be an application for it.
Any advice or suggestions are welcome
Thanks,
Bob