Comparing a string

[schmir1]

I can't get a string comparison to come out true. I'm attaching the file.

[Jim_Kring]

The "Equal?" function will compare the entire strings. What you are probably trying to do is test whether the first character of the serial read string is a "P". However, LabVIEW does not have a character data type. To do this comparison, use the "String Subset" function to return a string of length 1 starting at offset 0. Then compare this subset with "P".

Good Luck, - Jim

[Ben]

If Jim's readiang is correct, you may also want to concider using the "Match Pattern" combined with a "greter or equal to zero". This will let you know that the "P" was found and where.

Ben

[Jeremy Braden]

Don't forget to look for hidden characters like line feed and carrage return. You can see these characters by right clicking on the string object and sliding to slash codes display.

Jeremy

[schmir1]

Thanks for the answer. Works fine. I have a another question on my VI. Not sure if I should close this question and ask another or just ask it here?

Why does my error out status get checked and then go to an X.

Anyway, let me know if I should post as a new question.

[Jim_Kring]

That means that an error occured somewhere in a subVI. In order to know where it happened, you can can look at the "source" string; and to know what the error type is, you can look at the "code" number. Also, right-click anywhere on the error cluster and choose "explain error" to see a dialog that will give you more information and a suggestion.

Good Luck, Jim

[schmir1]

It's a time-out error. Seems like the timer doesn't stop in the Read Serial Port with Timeout vi. I receive the correct number of bytes and get the green check mark then the green check turns to the red X after the time-out value is reached. I need some way to reset the timer when the number of bytes received is reached. Any ideas. I'm attaching my modified Vi.