fixed point as case selector value solution?

[butterwaffle]

Hey all so I'm very new to LabVIEW and I'm trying to do a simple program.

Right now I'm have a numeric control which controls my analog input voltage on my sbRIO 9636 board(from the evaluation kit). Depending on the voltage I want to display a message onto the LCD screen. I know that you cannot use FXP values as case selector values. Is there any way around this? I was thinking about converting it into string, but I want to have a case where any voltage between 0-1 displays a message, then 1-2 displays a different message and so on and so forth up until 10.

[GerdW]

Hi butter,

well, integers are allowed for case structure selector input. So the easy way would be to convert your FXP to an integer (with some rounding applied)...

[butterwaffle]

Yeah I figured it out once I got on my computer that had LabVIEW on it..

I have another problem.

I have a case structure with a bunch of cases and an integer case selector.

I want to be able to display a message for each value. Between 0 to 1 volts would display "zero" and between 1 to 2 volts will display "one" etc. But the case structures rounds up my values, so anything that is >=1.5 will be automatically thought of as 2. >=0.5 is thought of 1. How can I get around this?

[johnsold · Accepted solution]

The rounding in the case selector is built-in and cannot be changed by the programmer.  You will need to do the logic externally and create the integer selectors you need.  One way to do this is to create a constant array with the values where you want to switch cases. Then do a comparsion to the variable value. Search the resulting boolean array for the first True. The Index coming form the search goes to the case selector.

Lynn

[crossrulz]

---

@butterwaffle wrote:

I want to be able to display a message for each value. Between 0 to 1 volts would display "zero" and between 1 to 2 volts will display "one" etc. But the case structures rounds up my values, so anything that is >=1.5 will be automatically thought of as 2. >=0.5 is thought of 1. How can I get around this?

---

If you are keeping with the integer numbers as the limits, just use Round to -Infinity to round down to the nearest integer and wire the result into the case selector.

[johnsold]

I knew there was an easier way I was missing!

Lynn

[apok]

[GerdW]

Hi butter,

didn't I mention "with some rounding applied" in my previous post?

[crossrulz]

---

@johnsold wrote:

I knew there was an easier way I was missing!

Lynn

---

The next simplest way I was thinking was using the Threshold 1D Array and then round the resulting index to -Infinity.  That would work well if the limits are not integers.

[butterwaffle]

Yep I found the Round to -Infinity in the numeric pallete! Thanks for the help all.