homing motors

[winterfresh11]

I am using two linear actuators, one in the x axis, the other in the y axis. I am using labview to program their movement. Previously labview would automaticaly send them to the home posititon which was with each motor all the way extended and this didn't take any extra code, it just happened before they were controlled with my code. My code would then move them back in at certaint distances. Somehow the homeing has switche so now the home postion is with the motors all the way in, and it reads a negative number when they are moved out from the new zero point. This is a problem because then my code can't move the motors in, they are already all the way in. I don't know what happened to cause this change, could use some help.

[SnowMule]

Are the motors going through some sort of multi-axis controller/driver, or are you driving everything directly and using some sort of data acquisition system/DIO to get limit switch inputs to the PC?

Did something actually change before and after, or is it just a different software tool running everything?  Does the old software still work as expected?

[winterfresh11]

The motors are plugged into a two channel controller. No software should have changed. Everything was working fine, and then all of a sudden after working on some code in the program running into a few errors the code seemed like it would work but this homing thing had changed.

[Albert.Geven]

Race condition in your code?
Show your code.

[SnowMule]

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@winterfresh11 wrote:

The motors are plugged into a two channel controller. No software should have changed. Everything was working fine, and then all of a sudden after working on some code in the program running into a few errors the code seemed like it would work but this homing thing had changed.

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Does the controller have a "home" feature on it? 

The motor controllers I've worked with in the past have all had some brains in them - configure the equipment parameters (Limit switch inputs on the axes, torque/accel parameters, etc) then in software you can just call "home axis" and the controller takes over and tells you when the axis is homed, then waits for the next command. 

http://www.parkermotion.com/manuals/6k/CR_h-i.pdf

[winterfresh11]

I don't believe that the controller has a "home" feature on it. I'm using 2 thorlab motorized stages. The x axis stage works fine now, it goes to its home and zero postion which is fully extended at 25mm. For some reason the y axis stage and motor thinks that its zero point is somewhere in the middle of its range. When I try to home it it will start to extend but runs into a problem when it gets too far. I believe that since it thinks its at zero in the middle of its range, it thinks it can go 50mm from there but it can't becaue the zero point is with the motor extended a bit, so maybe it can olny go 45mm if the zero point is 5mm extended from it being all the way in. That's just an example. Basically I need a way to reset this motor/stage or something so it know when it goes all the way out it is a zero, and it counts up as it goes in all the way to 50mm.