need an urgent help on LabView Coding

[Aashish]

Respected Sir,

                           i need an urgent help on LabView Coding and i have to sumbit it as quickly as possible.... please help me out.. all the details are in the attachments, along with the working... please, i beg.. help me out...

[Matthew_Kelton]

All of your issues depend on x and y being as you expect.  Are x and y behaving as you expect?

Do you have bounce issues?  You are not handling any relay bounce in your program.  If you are getting any bounce in your measurements, you may resetting all of your calculations.

[smercurio_fc]

It should also be pointed out that you have created a race condition with your misuse of the local variables. The "x" and "y" local variables are being read before their values have been updated from the DAQ operation. Use wires! Same goes for this bit of code in the "drop-off" VI:



As it is, this will display the "Timer" value for the previous iteration.


Message Edited by smercurio_fc on 05-21-2008 01:20 PM

[Aashish]

sir, can you please bulid a VI for me that-

1]From Relay Off to On Position-

 can initiate a timer (When 'x' is ON), as well as turn ON a Numeric Indicator that displays the corresponding input voltage and when ('y' is ON), stops both the timer as well as the indicator and they both hold their values and must have a reset button to reset the values...

2]From Relay On to Off Position-

 Also, now when ('x' and 'y' both are ON), when 'x' goes OFF, the timer should initiate and the indicator should display the corresponding input voltage and when 'y' goes OFF, both the timer and the indicator should stop, and they both hold their values and must reset their values..

Sir, will it be possible to use two use timers and two indicators for this purpose.. sir, please help me out, me in a complete mess...

[smercurio_fc]

It seems to me that your basic approach is flawed. Have you stopped to consider that you're trying to measure on-off times of relays which are, like, really really small time durations, and that you're trying to measure this with software? This is simply not practical, and some would argue simply impossible. If I were asked to measure drop-off time of a relay I would not try to measure that time using a software timer. What I would do is set up my DAQ system to read a waveform of points and then simply analyze the waveform for when the signal drops out. LabVIEW has built-in functions for signal analysis.

[Aashish]

ya, even we tried to explain these concepts to our project guide.. but he thinks that we are fools to tell him such kind of doubts.. but can u please bulid two vi's for me, that will be based on two led's,x and y..

1]both led's off-

when 'x' glows, it initiates the timer and as soon as 'y' glows, it stops the timer and the timer holds its value..

2]both are on-

when 'x' goes off, the timer initiates and when 'y' goes off, the timer terminates and holds its value..

also, can you guide us, how to hold the value stable of any indicator (using some loops or functions...)

[altenbach]

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Aashish wrote:
.. but can u please bulid two vi's for me, that will be based on two led's,x and y..

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I think you are misunderstanding the purpose of this forum. This is not a software service that writes plant quality software on demand and for free on a tight deadline. 😮

Is this a student project? Who wants this done and why are they asking you to do it?

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Aashish wrote:
also, can you guide us, how to hold the value stable of any indicator (using some loops or functions...

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I don't uderstand what you mean by that question. An indicator remains stable until you write a new value to it. You can for example place it inside one case of a case structure and activate that case whenever you want to update. If you want to keep a process value stable via feedback control (e.g. keep a temperature stable by regulating heating and cooling devices), you could look into PID.

[Avinash.gogineni]

Hey I am Avinash, even i am in need of some one help in preparing that VI. It's not related to my course even I just wanted for my professors project. Bu no one is helping to get that..... If u found any consu;tancies to do this job.. please inform me... my id: avinash.gogineni@gmail.com... plss reply soon

[smercurio_fc]

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Avinash.gogineni wrote:
Bu no one is helping to get that.....

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I find that difficult to believe, considering that your posts have had many answers. As noted previously, this forum is not a VI-writing service. Our goal is to help you understand LabVIEW concepts and to point you in the right direction. Ultimately you are the one who has to write and understand the code.