NewBoy
Member
Hello,
I have never done any motion control and the job I am working on is very simple. I will be monitoring the top and bottom position of a spray nozzle as it moves up and down inside large engine cylinders that vary in height from 12" to 60". The nozzle is moved up and down by a screw that will turn 24 RPM for correct nozzle speed (6" per min.) while spraying. The motor (through a gear box) turning the screw will be controlled by a VFD. At proper honing speed the VFD should be operating at approx. 35 Hz, so I should have good torque.
The plan is to run drive at 120 to 180 Hz to bring nozzle down to top of cylinder quickly and stop to allow for further user setup and then, when ready, operator can start the honing process. I plan to program a routine for each cylinder type/height (HMI for operator selection), use some sort of counter to know my position for reversing the nozzle. I can set up something so I can use a prox switch to count revolutions of the screw and use a standard counter in the PLC (Siemens s7200) which seems simple to me but should I use an encoder and a high speed counter in the PLC? Are there things I may not be aware of in motion control such as this that you can help with?
Additional things that you may need/want to know: Precision is not important, +/- 1/4 is fine. Also I plan on using the PLC to control the VFD.
Any setup and programming suggestions for this simple application will be appreciated and I hope the above gives you a picture of what I am trying to do.
I have never done any motion control and the job I am working on is very simple. I will be monitoring the top and bottom position of a spray nozzle as it moves up and down inside large engine cylinders that vary in height from 12" to 60". The nozzle is moved up and down by a screw that will turn 24 RPM for correct nozzle speed (6" per min.) while spraying. The motor (through a gear box) turning the screw will be controlled by a VFD. At proper honing speed the VFD should be operating at approx. 35 Hz, so I should have good torque.
The plan is to run drive at 120 to 180 Hz to bring nozzle down to top of cylinder quickly and stop to allow for further user setup and then, when ready, operator can start the honing process. I plan to program a routine for each cylinder type/height (HMI for operator selection), use some sort of counter to know my position for reversing the nozzle. I can set up something so I can use a prox switch to count revolutions of the screw and use a standard counter in the PLC (Siemens s7200) which seems simple to me but should I use an encoder and a high speed counter in the PLC? Are there things I may not be aware of in motion control such as this that you can help with?
Additional things that you may need/want to know: Precision is not important, +/- 1/4 is fine. Also I plan on using the PLC to control the VFD.
Any setup and programming suggestions for this simple application will be appreciated and I hope the above gives you a picture of what I am trying to do.