It sounds like you may have your home sensor configured as the reverse limit switch. The behavior you're describing matches the definition of the Find Home function in the NI-Motion Function Help:
When the search direction is forward, the axis starts moving in the forward direction. If the desired home signal transition is detected, the find home sequence continues based on the other control bits. If the forward limit switch is encountered before the home input, the axis automatically reverses direction and continues searching for the home input. Then, if the reverse limit is encountered before the home input, the sequence stops and the Home Found status is False. If a home input exists, finding it is guaranteed. A similar search sequence is followed when the initial s
earch direction is reverse, except the search starts in the reverse direction.
Take a look at your external wiring, and also make sure that the configuration in Measurement & Automation Explorer (MAX) are set up correctly.
Here is a document outlining MAX setup:
http://zone.ni.com/devzone/ConceptD.nsf/webmain/BCED4A210C9740E386256B9F00609EBF
Hope this helps-
Julie S.
