How to creat XY Grid Inspection Application with the modulo Breakpoints?

[soslotos]

I need to inspect a wafer that rests on an XY stage under a Laser

Scanning Microscope and acqure data using DAQ card.
To execute the row-by-row scan,I'd Iike use modulo breakpoints for

triggerring at a constant repeating interval.But I don't know how to
creat two dimensions moves with modulo breakpoints.

[Rodj]

Breakpoints are on a single axis, though that axis could be part of a vector space. There are two ways to solve this. First just pick an axis and have that axis generate the breakpoints. This is the simplest and most straight forward solution that is what most people do.

Second, have both axes generate a breakpoint and have external circuitry to AND the signals together. There are several issues with this method. A typical system has enough variability that you cannot count on both axes being at the breakpoint positions at the exact same time. This is the difference between theory and reality. So your external circuitry would have to allow for some window around each breakpoint or the AND condition would not consistently be true as you desire.

Also a little about the NI Motion Controllers. The NI-733x/4x controllers require you to re-enable the breakpoint after each breakpoint occurrence. This is a single shot breakpoint. The NI-735x motion controllers have two extra modes. Buffered Breakpoints which allow you to configure a buffer of arbitrary breakpoints which the board will execute for you. And Periodic Breakpoints that are like modulo breakpoints only the motion controller handles all the re-enabling. The difference is that the NI-733x/4x can achieve a 150 Hz breakpoint frequency and the NI-735x can achieve a 4 MHz breakpoint frequency.

Rodger S.