Think about the problem you stated. Let me suggest one way to break it down:
- You want to "blink" an LED.
- You want to have a sequence of Blinks for a number of LEDs.
First question -- how do you "blink" an LED? What does this mean?
Second question -- do you know how to "generalize" the first question so you can "plug in" the LED you want to blink?
Third question -- if you can answer the second question, how would you use this solution to come up with "Blink a specific LED a specific number of times"?
I'm uncertain how much LabVIEW experience you have. I, myself, am a Great Believer in sub-VIs. In particular, I would write a "Blink" sub-VI that has two parameters, a reference to the LED I wanted to blink and the blink On/Off Time. I might also "have my cake and eat it too", and include a third parameter, the number of blinks. The key "advanced topic" here is the ability to pass a reference to the Front Panel LED indicator, so that one sub-VI can do the work for any particular LED.
If you know about sub-VIs and using references, your problem becomes very simple -- Call Blink with a reference to LED1, a Blink On/Off Time, and the number of blinks, 2. Follow this (using the Error Line, which you should always put in the lower left/right corners of all of your sub-VIs, to connect to the first call to Blink) another call with LED2 and the same parameters. Voilà.
Suppose you don't know about sub-VIs? Well, start by thinking about how you would code Blink if you had the LED indicator available as well as the Blink On/Off Time and number of blinks.
How would you make a single Blink, given an indicator (LED1, say) and a Blink On/Off Time (I'm going to assume that if this is 1000, this means "turn on for 1000 msec, then turn off for 1000 msec, then we are done"). Hint -- you can do this several ways, but one is with a For loop that counts to 2 (the "on" + "off" states), a Boolean Shiift Register, your LED indicator, and a Time function.
So now what do you have to do to this simple "blink" to make it do multiple blinks (controlled by a Number of Blinks control)?
Once you have this worked out, i.e. how to make one LED blink as specified, figure out how to do the same thing for the second LED. The code should look very similar -- the main issue here is how you sequence the two sets of actions. There are multiple ways to do this, including stringing them along in a sequence (having an Error Line helps to "sequentialize" things) or putting them in a loop and choosing which alternative to do.
Bob Schor
