Reread msg #6 where I *did* give reasons for the parallel loops. The "technical" reason isn't much deeper than what I said -- sometimes interactions with a device might be time consuming. To allow *other* parts of your code to keep humming along, it can be helpful to isolate those interactions into a dedicated parallel loop.
Attempting to read a digital frequency from a signal that may not be pulsing yet can be one of those time-consuming interactions. But the good news is that such a timeout error isn't the end of the world. Yours seems to be a case where you could anticipate the likelihood of a Read timeout and write code that can deal with such errors when they happen. It'll often be best to set a shorter-than-default timeout value too, to limit the time you have to wait before your loop can iterate and do the next thing (try again? report error? restart motor? etc...)
Technical reason: frequency measurement depends on 2 active edges from the incoming pulse train to establish the time interval that determines the signal's frequency. There is no measurement until both edges occur. Edge counting merely reports the value of the device's count register when requested. The count itself is incrementing behind the scenes based on incoming active edges and the device's logic circuitry. The count *is* the measurement and it's always available, even when the count is 0.
Aside: it takes *time* to formulate fairly clear, fairly concise, but fairly useful responses. Sometimes all I've got is ~5 minutes while waiting for a test system to reboot. Something like that holds true for a lot of us. Sometimes it takes a lot of back and forth to finally "get there" as progress and knowledge transfer come in small increments due to time constraints.
We are trying, albeit imperfectly, to throw you a lifeline. So we get frustrated when you seem more interested in sawing at the rope than grasping for the buoy.
I'm done with free advice in this thread. PM me if willing to pay for consulting fees. Probably only an hour or so if you're well-organized and prepared, two or more if not.
-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.
