Making a counter with enable and reset

Question

Hi.  
First of all, I looked online for this solultion and no success.
What I am trying to do is have a counter with enable and reset.  
1.  Increment from 0 to 5 everytime true boolean is received.  Q, the output should then be 1
2.  If boolean false is received, Q should be 0
3.  Once the count reaches 5, reset the counter to 0 and repeat.
4.  Step 1-3 only happens when enable is true.  Anytime enable is false, the process is stopped.
Please help!
Rose

Answer 1

This is something called an Action Engine, closely related to "Functional Global Variables" (FGV) or "VI Globals" (VIG).  Basically, you have a While Loop with one or more Shift Registers acting as "memory" and an "Action" input (typically a Boolean or an Enum) that says what the Action should be.
As you posed your problem, I'm unsure if you require one Boolean (Enable/Disable) or two (Enable/Disable and "Count").  This is a situation where having an Enum input and more "Actions" might be appropriate.  For example:
Load      Save the Max Count (5 in your example) in a Shift Register
Reset    Set the internal Count to 0
Enable   Allow Count Action to proceed
Disable  Don't allow Count Action to proceed
Count    Increment counter if "enabled", and output current count
Each time you call this VI (did I say that this should be written as a sub-VI, with inputs Action and Max Count, and output Current Count?), depending on the Action you wire in, you will either perform "setup" actions (Load, Reset, Enable, Disable) or "Counting" actions (Count).  Note that it is easy to modify it so that if the Counter is disabled (ooh, that's a good name for this sub-VI, "Counter", has a mnemonic ring to it), the output is, say, -1, "Not a Count", instead of (as I described it above) the last Count while Enabled.
Action Engines (and similar constructs, where there's a While loop with "True" wired to the Stop terminal, useful as a "memory" unit) are pretty common in LabVIEW.  More accomplished LabVIEW users might also accomplish this with a Feedback loop, but I find that the "Do Once" loop shown above is easier for me to recognize and understand.
Bob (hard to teach an old dog new tricks) Schor