Creating a User Interface which Processes a Continous Stream of Data

[mkhan_1]

Hi all,

The program: I am trying to create a program which takes in a continuous stream of data from an external source. The user can interact with the front panel to do various things such a plotting the data, starting a calibration process, stopping a calibration process, etc.

I have attached a VI which a very simplified example of what I am trying to do.

In this VI, loop 3 is taking that live stream of data and processing it into various doubles, strings, etc. and passes that data via a queue to loop 2. Loop 2 is what does all the logic and display for the program (In actual application, I would have many sub-VI's inside here to do this). Loop 1 is what handles the user inputs. So far, the solution I have been able to come up with is using local variables to take the user input from loop 1 and select the appropriate process in loop 2. This is functional and would work but I am wondering if there is something better.

The problem: How can I do this without using local variables?

• I have considered using an event driven state machine but to my understanding, the issue with that is once a process has started, you cannot do anything until the case returns to the "wait for event" case.
• I could combine loop 2 and 3, get rid of the data1 queue entirely and then use queues to pass the enum state/cases from loop 1. However, the issue with this is that combining loop2/3 would be too much processing for a single loop and would slow the whole program down.

Thanks,

mkhan

[Mark_Yedinak · Accepted solution]

Change the data content you use for the queue to loop 2 to be a cluster with a command (ENUM or String) and a variant for the data type. When you dequeue a message check the command type first and use that to select the case you will execute. any given case/command will know the data format for the specific command and can call variant to data with the appropriate typedef for the data. This way both loop 1 and loop 3 can send messages to loop 2.

[mkhan_1]

That is a great idea actually. I will try that.

Thank you!