Mathscript Probe Window (LV 2009) Not listing all variables

Question

Please see the screenshot below. The Mathscript probe window is shown on the right of the VI block diagram. The execution is at the breakpoint on the last line (blue arrow). 
Why is input variable "a" not listed in the probe window? I see this behavior that some variables are not listed in the probe window.
Thanks,
AJ

Answer 1

Hi AJ,
There are a couple of things that may be going on when variables fail to appear in the MathScript Probe. The first is a bug with the MathScript Probe in 2009. Sometimes input variables either fail to appear or briefly appear then immediately disappear. The good news is that this bug (CAR #182784) is scheduled to be fixed in the next service pack release of LabVIEW. I'm not sure if Nickerbocker's workaround will work. If it doesn't, you could also try adding "a = a+0;" to the top of your script.
Another occasion where variables will fail to appear is if they are defined within your script but never used. This case is analagous to placing a constant on a LabVIEW block diagram and not wiring it to anything. In this situation, there is no wire to probe; the only way to see the value at run-time is to look at the code itself. It's a similar situation when you define a variable in MathScript without using it; the MathScript Probe cannot report the variable because it doesn't have a corresponding "wire" so you have to look at your MathScript node to see the value.
Please let us know if you notice missing variables in situations other than the above two cases.
Thanks,
jattas
LabVIEW MathScript R&D