Changing an output box in a case structure to an input box

[Muhammad Asfour]

Hi, I have been struggling with the following problem in Labview:


Hi, I was working on a wiring diagram in Labview and I was trying to
wire an absolute value symbol to the right border of a case structure.
The problem is that I get an output box (an white filled box with an
orange border) instead of an input box (an orange filled box). How
would I change the output box into an input box? I have tried Ray
Kong's method, which is to add a constant and that would make the box
solid. It worked only once but when I tried it on another output box
it did not work. Any suggestions would be appreciated. Please
include step by step instructions as I am still learning Labview.

Thank you

Muhammad Asfour

[Labviewguru]

Muhammad,

First off, I strongly recommend that inputs be placed on the LEFT of any structures in LabVIEW. Dataflow is typically from left to right.

Second, the determination of whether a tunnel (the "box" you speak of is called a data tunnel) is an output or an input is determined by what it is wired to. Data that originates outside of the structure and is connected to the input of a node inside of the structure (or just connected to the structure) is an input tunnel. Data that originates inside of the structure (the result of an output from a node) is always an output tunnel on that structure. While this is in fact independent of the location on the structure, it is common practice, and recommended, that inputs occur on the left of a structure, and
outputs on the right.

Of course, this all begs the question as to what exactly you are doing that you have a tunnel that is not the input/output that you want.

If this doesn't help, either post again, email me.

Also, pick up a copy of "LabVIEW for Everyone" by Jeffrey Travis, and possibly the LabVIEW Basics I and II CDs from NI. These are the best tools for learning LabVIEW. That, and going through the examples database in LabVIEW.

[Jim Adams]

The box type will be appropriate for what you have wired to the box.

When you say you want an "input box", do you REALLY want an input box (ie, a
connection bringing a value from outside of your case statement to the
inside of your case statement) or do you mean that you want your output box
(a connection bringing data from inside your case statement to the outside)
to be solid orange? The output box will go solid orange when you have a
connection from EACH case to the box. Remember that a single output box
(usually on the right side of the case statement) must be connected to
something in each case of your case statement. It will be filled white
until all cases are wired.

Write back if this isn't clear of if I have mis-understood your situation.

Hope this hel
ps.

Jim



"Muhammad Asfour" wrote in message
news:910d89e8.0207050750.343f0b27@posting.google.com...
> Hi, I have been struggling with the following problem in Labview:
>
>
> Hi, I was working on a wiring diagram in Labview and I was trying to
> wire an absolute value symbol to the right border of a case structure.
> The problem is that I get an output box (an white filled box with an
> orange border) instead of an input box (an orange filled box). How
> would I change the output box into an input box? I have tried Ray
> Kong's method, which is to add a constant and that would make the box
> solid. It worked only once but when I tried it on another output box
> it did not work. Any suggestions would be appreciated. Please
> include step by step instructions as I am still learning Labview.
>
> Thank you
>
> Muhammad Asfour

[mikeporter]

One thing to be aware of is that it can be very easy to get two of these boxes lying right on top of one another. When I get into this type of situation, I typically delete the input or output box and rewire things from scratch.

Mike...

PS: in terms of the question of which way dataflow "is supposed to go", left to right dataflow is wonderfully logical--as long as you come from a culture where the natural flow of words is in that direction. What happens when a person grows up reading right to left, or top to bottom? Suddenly that thing that seems so intuitive to us is just one more thing to be learned--one more hurdle to be overcome in learning the language.

What LV really needs is a control strap in the *.ini file that allows you to set the orientation
of the program. Left-to-right, right-to-left or top-to-bottom. (Are there any languages that read bottom-to-top?)