Breakpoint Mode

All of the following modes are available for all NI motion controllers unless otherwise specified.

Absolute

This mode is available in both single and buffered operation. The breakpoint position is interpreted with reference to the zero position (origin) and can be anywhere in the 32-bit position range. This also applies to all the position data in the buffer for buffered operation.

Relative

This mode is available in both single and buffered operation. For single operation, the breakpoint position is interpreted with reference to the encoder position when the breakpoint is enabled. For buffered operation, the first position data is interpreted with reference to the encoder position when the breakpoint is enabled. The subsequent position data is interpreted relative to the previous breakpoint such that:

Breakpoint[0] = Position on enable + Buffer[0]
Breakpoint[n] = Buffer[n-1] + Buffer[n],
where n>=1.

Modulus (7330/40/90)

This mode is available only in single operation. Modulus breakpoint is used to specify multiple breakpoints with a constant distance between them. The breakpoint position is interpreted with the modulus range such that

Breakpoint[n] = Breakpoint position + (n × Breakpoint modulus),
where n is any integer.

Note  For modulo breakpoints, the magnitude of the breakpoint value must be less than the breakpoint modulus. If this range is exceeded, a modal error is generated when you execute the Enable Breakpoint Output VI or function.

When the breakpoint is enabled, the controller enables the two breakpoints closest to the current position, one in the forward direction, and one in the reverse. After a breakpoint occurs, you can re-enable the next breakpoint without loading a new position.

Periodic (7350)

This mode is available only in single operation. Periodic breakpoint is an enhanced version of modulus breakpoint. The period determines the distance between each breakpoint:

Breakpoint[n] = Breakpoint position + (n × Breakpoint period),
where n is any integer.

When you load a breakpoint position, it is interpreted as the first breakpoint. After this breakpoint has occurred, the breakpoint status is asserted and the subsequent breakpoint is automatically loaded and enabled by the controller.