temperature to waveform chart urgent homework help!

[EngineeringBizi]

Hi everyone! So this is my first ever post as I am completely new to this programme. I have been given a homework to create the following in speechmarks. I wondered if someone could please urgently be kind to take me through this step by step so I can understand what he is doing and follow him at the same time. Thanks so much!

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"Complete a VI that records temperature to a waveform chart using either the Random Number function. Use Property Nodes to change the properties of front panel objects programmatically.

During execution, the VI performs the following tasks:

• Enable the user to control the execution time using Wait Until Next ms Multiple
Function.

• The VI must run until either the ABORT button is pressed or the number of user
defined Points to Acquire is met.

• Determine the increments between points by setting the x-axis value on the
Waveform Chart to change according to the duration of run time of the VI which
depends on the delay value set by user. Use XScale Multiplier Property Node.

• Clear the waveform chart so it initially contains no data every time the VI is executed
using the History Property Node.

• Change the colour of a plot if the data exceeds the user defined value. Use Active
Plot and Plot Color Property Nodes.

• Blink an alarm indicator if the data exceeds a certain value. Use Blinking Property
Node.

HINTS:
• Use Bundle Function to combine and display both the threshold and generated value
on waveform chart.

• Add the following property notes to the waveform chart:

XScale Multiplier

History

Active Plot

Plot Color

• Add the following property node to the alarm indicator

Blinking"

[johnsold]

Welcome to LabVIEW.

Since this is a homework assignment, we will not provide you with a VI, because you learn more by doing it yourself.

This is a fairly sophisticated requirement for a beginner.

Start by breaking it down to simpler parts.

For example you could write a VI which does just the part required by the first sentence. That will take you about two minutes.  It may not be very pretty but should give you random numbers on a chart.

Then add the timing requiement part.  This does not change any of the code you wrote for the first part but adds to it.

Next. Tell the instructor that many experienced LV programmers and the LabVIEW Style Guide (Google it) recommend NOT using the Abort button to stop VIs. (page 6-20 of the Style Guide)  Put a Stop button on the Front Panel instead.

Read the help files about Property Nodes to see how they can help you do most of the rest of the requirements.

Post back with specific questions.

Lynn

Using LV since version 1.2

[GuenterMueller]

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@johnsold wrote:
[...]

Next. Tell the instructor that many experienced LV programmers and the LabVIEW Style Guide (Google it) recommend NOT using the Abort button to stop VIs. (page 6-20 of the Style Guide)  Put a Stop button on the Front Panel instead.

[...]

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Kudo for this, Lynn.    Taking this into account right from the beginning is a brilliant starter.   

I fully agree with your other recommendations on how to start the project and how to manage the evolution.

[johnsold]

GuenterMueller,

Thank you for the comments (and kudos).  I hope the instructor will look at the Style Guide.  It is really disappointing that students are given bad advice right at the beginning.

Lynn

[EngineeringBizi]

Thanks a lot for your help!

As you can see this is something hard that has been put us on. Just to clarify when I said 'homework' it's for us to go and find out so asking for help (which I asked the teacher by the way) isn't a problem he just wants us to see how it can be used and think of different ways we can use labVIEW. There isn't an assessment or anything it's simply to get a feel, but I think I'm not as intelligent as the others.

I went to the library last week and they had no books on labVIEW!! Online the books were extremely expensive so through google I then found this. The only think I know to do on is open up labVIEW and then I know there's a front panel.

I know that STOP button, the teacher showed us a red stop button, maybe that's what he meant.

Like I don't even know what the teacher was asking for, I'm just not smart I guess.

[EngineeringBizi]

Can you provide me like a walkthrough, like making sure I understand.

[GuenterMueller]

As Lynn suggested you should break your code in to pieces.  A good starter is "Complete a VI that records temperature to a waveform chart using either the Random Number function. Use Property Nodes to change the properties of front panel objects programmatically."

Create a new VI  and place a waveform chart on the front panel.   On the block diagram, wire the Random Number to it.

When you run this VI, a random number is generated and written to the chart.

[johnsold]

Start with the On-line tutorials on the NI web site. Search for Getting Started with LabVIEW or something similar. Note that NI's search sometimes does not work as well as Google.  Put "NI" or "LabVIEW" in a Google search along with the specific thing you want to find.

When you have LV running, always keep the Context Help window visible.  The Detailed help links at the bottom of that window are extremely valuable for getting more information about how things work.

The red octagon on the toolbar is called the Abort Execution button (Abort for short). A long time user of LV, Ed Pickens, wrote on the Forum that "Using the Abort button to stop a VI is like using a tree to stop a car. It works but there may be unintended consequences!"  It is far better to drop a button from the Boolean palette on the Front Panel and use that.  Some of the palettes have buttons marked Stop. They do not do anything special but it saves you some time because you do not need to customize the labels and boolean text.  I am not telling you do do something which is in direct opposition to the instructions your teacher gave. I just want you to know that there is a better way. If you ask the teacher to look at the Forum, we can help make sure he does not encourage to to pick up bad habits.

LV is both very simple and extraordinarily complex.  It is fairly easy to get some simple things running. But it also has the power to run very complex programs.  Space X uses LabVIEW for controlling their rockets to the Interntional Space Station.

Don't get discouraged.  You found the Forum and no one else from your class has posted here yet, so you may be the smartest of all.

Lynn

[GuenterMueller]

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johnsold wrote:

Don't get discouraged.  You found the Forum and no one else from your class has posted here yet, so you may be the smartest of all.

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And as you see there a couple of guys even answering on the weekend.   If you post your issue on a working day there is usually even more feedback.

[EngineeringBizi]

This place is amazing, I can't believe how I found this place! Thanks. When I work on it on the computer tomorrow I will keep you updated. Thanks a lot.