setting a valid range for a motor

[Rhayes]

I have been pulling my hair out thinking of this one!

I thought I had it but no such luck.

Here is what I need to do.
I have a stepper motor and each step is counted, if a limit switch closes telling the software that the motor has fully opened then the motor should reverse, same thing with the closed limit switch at the other end. There is a valid range in which the switches can close, anything else will cause a fault.

But here is the tricky part, if a limit swith isn't detected within 500 steps of an upper or lower step value then the motor should reverse anyhow.

The outputs I need are:
Direction(toggles)
Step(each pulse steps the motor)

I'm using Labview 4.0 so If you wish to show me anything I'll need a graphi
c only.

I'm displaying what I have as a graphic.
btw the whole limit swithing test is in the top left corner.
Thanks

Ron

[vicky]

Hi Ron,
If i try to just tell you what you want is,you are looking for control which automatically detects the 500 steps and it must reverse the direction of what was previous,if i am right,this is the solution you will have a count of steps from the upper or lower step so you put a OR condition for the limit switch control,and keeping track of the present of the direction and inverse it using SHIFT REGISTER, i am sorry if i have usderstood a wrong thing,plz expalin if i am wrong.