Find Reference
You can use these functions to initialize the motion system and establish a repeatable reference position.
Typical closed-loop motion systems use incremental feedback to keep track of position. At power-up, this position is meaningless until a zero reference position is established. Open-loop stepper systems must also be initialized at power-up.
NI-Motion provides two built-in functions, Find Reference and Wait Reference, to accomplish these tasks. Find Reference performs search sequences to find and stop on a specific edge of the home input, find the next instance of the encoder index, find the center of travel between forward and reverse limits, or find the forward/reverse limit. Wait Reference returns when an initiated find has completed. In this way a repeatable reference position that is accurate to one encoder count is established.