hovercraft control front end

[sudarhshan]

Dear All,

                I am doing project for my final year engineering on hovercraft front panel using labview.Here i have attached my vi.Please some one go through this.

I am recieving serial input and display the temperature in thermometer display.Problem is as soon as the serial  read executed and diplayed the temperature in the thermometer display the thermometer displplay will come back to 0 reading,it will not continously display the result.

suggestions needed,

                                        I need to implement the sensor right ,left and straight,which is ultrasonic sensors which finds the enemy present in the proximity of sensor and i need to dispalay the distance between sensor and enemy which is also input from seril input to labview.how to implent it.

Please some one help me out to get done this job.

Thanks and Regards,

Sudarshan

[Stuart.Parkinson]

Hi,

I assume that being a final year engineering student you are familiar with the general concepts of programming. Whether you are programming in a text based language or in Labview, the concepts are the same. If you want something to perform the same action repeatedly then you need to put a loop around it - you have no loop in your program. Just take a moment to think about what you are trying to do. Draw a flow chart or some other specification for your program so you know exactly what you are trying to acheive. I'm sure you must have been taught to do this.

From your description I assume you must be running the program with the 'Run Continuously' button - this is no good as a substitute for a loop.

If you can write a flowchart or some pseudo-code detailing exactly what your program needs to do, then you will have a lot less trouble coding it.

[mikeporter]

You didn't mention the kind of engineering your degree will be in. Or to put it another way, is the point of the project to build a hovercraft and the control software is a "necessary evil" to make the hardware work; or will your primary grade be on the software and the hovercrraft is just a "cool application". Or something in between?

But your requirements -- always the place to start -- tell me that you application needs at least two separate processes running in parallel.

You have a remote system that is spitting out data on a timed basis. One process will encapsulate the handling of that interface. This handling includes -- but is not limited to -- establishing the connection, error handling, dealing with communication loss, reading data from the interface, and validating received data.

The other process will implement your GUI. It should be event-driven.

Other potential processes that might need to be in separate processes now or in the future would include event management, and data logging.

Mike...

[NapDynamite · Accepted solution]

LabVIEW, by default, "re-initializes" every control or indicator to the default value (zero). 

The reason why you need to put your code inside a loop is very intuitive and a "common-sense" knowledge. You need to tell computer to keep executing your program for a fixed period of time or till you force it to STOP. If you don't do this, your machine will execute each and every instruction once and then, period. Imagine an aircraft that's running a position control code (the brains) inside a hardware, without a loop. It will run once (for a duration of few microseconds) and then your aircraft will have no brain to decide what to do. So it will crash. Millions of lives will be lost. 

Loops are the necesary "energy" to keep your code alive for a time. Your code will run once, and after it's done executing, it's controls and indicators will go back to thier natural state i.e. ZERO. 

This may be one of the reason of your problem. Try putting a WHILE LOOP with a FALSE boolean constant hooked up with the condition terminal. Or simply wire a boolean control in OFF state. If still you're getting no temperature readings, or getting reading in a fashion as you've mentioned, then there must be some issue with the acquisition device you're employing to measure temperature.

Try putting loop first, observe and come back here again. 

Another major logistic you need to take care of is the SUBJECT LINE. Do not mention the title of project in which you're facing issues. You're problem deals only with a portion of your overall design. Try to come up with brief, to-the-point subject. For example I have a robot (overall design) where I'm not recieving ultrasonic sensor data (a protion of design) because the timing and sycnhronization is kind of NEW to me in LabVIEW FPGA (sub-portion of portion of overall design). So my subject line would be, Timing and Synchronzation for Ultransonic Sensor in LabVIEW FPGA. 

Regards,