Home Positioning Routine

I am trying to develop a sub-routine for a home positioning. I have several pneumatic valves and one DC Motor that will use in this routine. I do have a general idea of what I need to assemble this code, but would like some input on standard routine that are already used in this application.

I am not trying for free hand-outs...just pointed in the right direction.

Thanks

rmonroe

Well, this depends on exactly what you are trying to do.
I use a lot of SEW servo drives, and each has to be setup for a homing sequence.
There are six homing sequences to choose from built into the drive, and I use different ones for different applications.

What you need for homing is firstly a home position, a sensor for that home position and a method for always getting to that home position no matter the starting point. This is usually done by having overtravel sensors. Your drive will start moving in one direction first, if it hits the overtravel, then it changes direction until it gets home. A popular scheme is to use one of the over travel sensors as the home position.
After that, if necessary, you can work on methods for gaining precision. This can be by using a relatively moderate speed to find the home sensor, then switch to a low speed to find the exact home position. SEW also use homing off the zero paulse of the encoder to give extra precision. Others I have seen use sensors with a high repeatability.
Pneumatics are generally easy, since they usually can only be in one of two positions.

I am going to create a sub-routine that will home all device plus stack messages if they are not home. I am using the Micrologic 1200 with a PanelView 300. I appreciate your input into this matter and I am open to any constructive input.


Again thanks for taking the time to response to this posting.

rmonroe

I've red your message twice but I still don't understand the point of the question Just define "home" position for each particular device (valve, drive) that comprises the system and send it to this position whenever you need to (pushbutton on HMI for example). Keep in mind phisical interlocks to prevent damage of moving parts...