A question about converting ASCII code in my vi to give time signals in numerical form

[yukfai88]

I have currently done a vi for getting time signals from a GPS receiver, the data to be shown is in ASCII format. I would like to extract the time signal as circled in red in the "time signal" attachment. How could my vi be modified so that the signal can be extracted from the line starting with "$GPGGA, xxxxxx.xxx, ...." ? I have attached my vi in the post. Can anyone help me? Thank you.

[MikeS81]

Hi yukfai88,

your data is "," seperated, so you can use the spreadsheet string to array function. Use index array to get your element.

Mike

[yukfai88]

Thank you, Mike. I can obtain the time signal once I have the first row detected is starting with $GPGGA. However, if the first row is invalid number (during start of the receiver), then the result is also invalid.

I would like to ask, whether there is a solution for detecting the heading of the string to be "$GPGGA" as the first row may be invalid, and "$GPGGA, ..." appears continuously in 1 second interval.

Sorry for not having clarifying the question.

[MikeS81]

Hi yukfai88,

you can use the "Match Pattern" function with "^$GPGGA" to check if this is the first part of your string.

Mike

[yukfai88]

Thank you for your help, my final question is how can I modify the vi to get a continuously updating "element" as specified, because the signals are continuously transmitting to the computer.

[MikeS81]

Hi yukfai88,

what do you mean? Which vi do you want to modify?

You can place all the functions into your loop to check your data.

Mike

[yukfai88]

Hi Mike, I have attached my recent work, and enclosed the parts i am in doubt with red circle.

- The left circle only shows change of value once, after pressing the run button of the vi. How can I modify the vi to get Time (String) changes continuously?

Thank you very much.

[MikeS81]

Hi yukfai88,

you build one string from all your data, so you read everytime the same time value. You can either store an offset in a shift regsiter, or you cut the string after the data you already worked on.

Mike

[yukfai88]

Hi Mike,

I understand what you mean for my concatenating all string into one string, but how can I store offset in shift register? Sorry that I don't know the way to do so.

yukfai88

[MikeS81]

Hi yukfai88,

no problem. You can do it like this.

Mike