Reverse Limit Polarity is the bitmap of active polarities for the reverse limit inputs: Axis 1—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 2—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 3—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 4—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 5—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 6—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 7—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 8—If TRUE (default), active low/active open. If FALSE, active high/active closed.
	Forward Limit Polarity is the bitmap of active polarities for the forward limit inputs: Axis 1—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 2—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 3—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 4—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 5—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 6—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 7—If TRUE (default), active low/active open. If FALSE, active high/active closed. Axis 8—If TRUE (default), active low/active open. If FALSE, active high/active closed.
	Board ID is a unique number assigned by Measurement & Automation Explorer (MAX) used to send and receive commands and data to or from a specific NI motion controller.
	error in (no error) describes error conditions that occur before this VI runs. The default input of this cluster is no error. If an error already occurred, this VI returns the value of error in in error out. The VI runs normally only if no incoming error exists. Otherwise, the VI passes the error in value to error out. The error in cluster contains the following parameters: status is TRUE if an error occurred before this VI was called, or FALSE if not. If status is TRUE, code is a nonzero error code. If status is FALSE, code is zero or a warning code. code is a number identifying an error or warning. If status is TRUE, code is a nonzero error code. If status is FALSE, code is zero or a warning code. Use the error handler VIs to look up the meaning of this code and display the corresponding error message. source is a string that indicates the origin of the error, if any. Typically, source is the name of the VI in which the error occurred.
	Bd ID Out is provided for flow control. You can string together NI-Motion VIs by wiring the Bd ID Out terminal of one VI to the Board ID terminal of the next VI.
	error out contains error information. If error in indicates an error, error out contains the same error information. Otherwise, it describes the error status that this VI produces. status is TRUE if an error occurred, or FALSE if not. If status is TRUE, code is a nonzero error code. If status is FALSE, code is zero or a warning code. code is a number identifying an error or warning. If status is TRUE, code is a nonzero error code. If status is FALSE, code is zero or a warning code. Use the error handler VIs to look up the meaning of this code and display the corresponding error message. source is a string that indicates the origin of the error, if any. Typically, source is the name of the VI in which the error occurred.

Using This VI

The Set Limit Input Polarity VI defines the active state for each forward and reverse limit input as either active low/active open or active high/active closed.

When configured as active low, the input is active when there is a low signal on the input pin. Conversely, active high means that the input is active when there is a high signal on the input pin.

Configuring an active state of active open or active closed does not correspond to the level of the signal on the input pin. Instead, an active open state means that the input is active when current is not flowing through the optocoupled input. Conversely, an active closed state means that the input is active when current is flowing through the optocoupled input.

You can enable limit inputs to cause halt stops when the input becomes active with the Enable Limits VI. You also can use a limit input as a general-purpose input and read its status with the Read Limit Status VI.

Example

To set the active state of the forward and reverse limit inputs on axes 1, 2, 3, and 4 as active low and the forward and reverse limit inputs on the remaining axes as active high, call the Set Limit Input Polarity VI with the following parameters:

Forward Limit Polarity corresponds to the following.

Reverse Limit Polarity corresponds to the following.