How to sychronize data acquisition and actuator control

[KFod]

I am working on a program that controls a PI M-235.2DG actuator while collecting and storing data from a Keithley 2000 multimeter. The behavior of the actuator is dependent on the data being supplied by the multimeter. If the voltage value being read is above or below a certain constant, the actuator changes its movements. This is done with a "Greater or = ?" comparison and an array. I have both the data acquisition and actuator control in one giant while loop to ensure that they run in parallel. 

Unfortunately, this program failed to control the actuator and provide a constant stream of data. I have used programs in the past that have accomplished this, but the addition of the "Greater or = ?" statement and the inclusion of the actuator controls in the while loop seems be causing problems. Any tips?

P.S, I have included a copy of the vi.

[Bob_Schor]

I'm sorry to inform you that this VI exhibits a multitude of faults that indicate whoever wrote it (a) never had any instruction in LabVIEW, (b) never viewed any of the on-line LabVIEW tutorials, (c) doesn't understand the basic underlying LabVIEW concept of Data flow, and (d) has not "studied" LabVIEW (meaning "read a book", "spent time with a LabVIEW Guru to Learn Wisdom", "studied the Examples and Sample Projects that ship with LabVIEW to see how the "Experts" do it).

If this is something that you really need, my advice would be to prepare a 2-3 page (or longer) detailed description of what you want the program to do.  Describe carefully all of the inputs, outputs, things to be controlled, etc.  Be sure to mention any hardware with which the program needs to interface.  Once you have all of this Documentation (which you should do before embarking on serious coding), find a good (or at least decent) LabVIEW programmer and hire them for the job.

If your original programmer wants to try to make a "go" of this, hand him (or her) the Documentation that you produced in the previous paragraph and insist that they spend a few hours with the on-line LabVIEW Tutorials.  Also suggest that they study the Examples and Sample Projects to see examples of good LabVIEW code.

Bob Schor