I'm going to say this bluntly. Given the conversation & code so far, you don't seem to be ready to tackle this right now. I say this to be constructive and save you from wasted time -- my best advice is to prepare to either:
1. Spend a *lot* of time learning LabVIEW, stepper motors, and mechanics and dynamics of motion systems while regularly tinkering to "bring the lessons home". Probably many weeks at minimum, could easily be more if you only have limited time for this.
2. Spend a relatively small amount of $ to purchase a stepper controller that can do the trajectory generation for you in response to simple communication commands.
Sorry, I've been away from any notable stepper work for more than 2 decades, so I don't have any specific recommendation. My guess is that there are plenty to choose from now in our "Maker era".
On the plus side, the pic you shared in another thread makes this look like a pretty simple motion system. NEMA 42's are lower inertia and thus more forgiving of mediocre frequency trajectories. The lead screw pitch will help reduce the loads (friction & inertia) seen by the motor. There's still things for you to learn, but at least the general mechanics of your system aren't pushing the envelope.
-Kevin P
ALERT! LabVIEW's subscription-only policy came to an end (finally!). Unfortunately, pricing favors the captured and committed over new adopters -- so tread carefully.
