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Certification
Sample Exam Solutions for Review
@A.E.P wrote:
Again, thanks for your comments.
Jeff:
Hmm, as I see it, my application already handles it.... If you click on the setup button, you can type 1 in the index, and you are able to add one more. The program cycles through that as well.
Hmm...: While typing. Maybe I just realized that I misunderstood that. So, they want to add another Zone, like North-West?? That will require a new item in the drop-down list as well as new Zone Indicators. Is that what they really want??
Yeah, I know I use much space. Maybe I will try not to, when I make the last sample exam 🙂 Do you think I will get a hit in the score due to that?
billko
I like your idea. But isn't it what I have already tried to do in this (Sprinkler) sample exam?
Oops, a comment on your question to Jeff above. I think you understood it correctly that your app should just be able to handle more array elements - like repeating zone coverage - not like adding new zones. I'm thinking that all you need to do in the setup is enable the array so you can add new elements, just like you did.
I am curious - in my sprinkler exam, I made sure to write the new settings back to the config file as part of the start state just because I felt that writing back to the config file was implied where it said "Note: The application should be scalable to handle additional elements of the Zone Setup array without any modification of the program." I felt that you weren't TRULY handling new elements until you made them permanent. But that was my interpretation, and it was partially because I felt the requirements were incomplete without it.
My advice is simple. Practice over and over and over again until it is boring. Develop a routine because this is what will carry you through when you first look at the test and want to panic. Instead of panicking, you will just do your routine, do something familiar (all setups will be similar), give yourself the confidence you need so that when you get to the unique part, you will be able to tackle it.
I got it down so well that I predicted EXACTLY what my score would be before I even got to the test site.
@kbrezina wrote:
Hey guys!
Here's my sprinkler controller solution. I think I spent around 3.5 hours on it.
Think it would pass?
Thanks!!
Where's your project? I'ts a sure fail without it. Did you just forget to include it?
I'm not a fan of unattached property nodes, but I don't know if they take points away for that, either.
I don't like that your Zone Indicator is sometimes left with the default values. While the EFFECT is what you wanted - the indicators return to all false - that's more like cutting power to the LEDs than reading the actual state of the imaginary zone sensors.
You have zero error handling. The docs say you must have error handling.
You don't need a timeout in your event loop. The event structure will be quite happy waiting around for something to happen. You don't have to give it something to do. Infact, you have just turned your event handler into a button poller. (I know why you did it - it's so the event loop can exit when the bottom loops stops, but there are better ways to stop the two loops.) In fact, this would probably be a good time to go thropugh the shipping examples and/or online tutorials to familiarize yourself with the standard LabVIEW design patterns. You need to use a recognizable design pattern. They all have rudimentary error handling and defined ways of exiting the loops.
The "Initialize" state isn't for "future development." Your initialization actually occured in your "Start" state, which I assume is the equivalent of the "Start (Application)" step in the documentation. (Hint: it would probably be better if you name your states the same as the documentation. For the test, it will be much easier for the grader to follow along. In real life, your software may not pass QA as it isn't clear what requirements are covered where.)
You can't save your edits to the csv file. Although it doesn't explicitly say that the data needs to be saved, IN MY OPINION, it is implied when the docs talk about scalability. It is in no way clear, however, and you probably won't get any deductions, especially if you explain it, so the grader won't think the omission was because you ran out of time.
It's generally pretty sloppy. You'll get points off for wires running behind objects and unecessary bends.
You have entirely too many tunnels set to default values. This means that data cannot travel from one state to another. it doesn't matter how many shift registers you have if the data cannot get there. You'll end up passing around the default values instead. To be fair, I don't think it will make any difference the way you set up the VI, but it's generally good practice to set the tunnels to "linked input tunnels". One day you will be beating your brains out for a few days trying to figure out where your data is disappearing to and you will find it was because a tunnel was passing default values instead of what was in the shift register.
You have exactly one subVI. Besides breaking your application into clearly defined steps - which makes your code extremely easy to document - subVIs make for a cleaner block diagram because you aren't constantly making room for stuff and making spaghetti in the other states. If you made your file read and your water pressure good selector into subVIs, your block diagram would be nice and tidy - and small. I forget where I heard it, but a good rule of thumb is: If you can't explain your VI in a paragraph or two, it's probably too big. That goes for your main VI, too!
@kbrezina wrote:
Bill,
Thanks for the feedback, I really appreciate your time!
In hindsight, I certainly missed a few obvious things, such as putting it in a project and handling errors. I do these daily, so I'm a little surprised I missed them.
I definitely made some bad decisions for the sake of time management, such as the default tunnels to help debug faster, the sloppy wiring, and the lack of subVIs.
Nice catch on the "future development" comment, haha. The first thing I did was make an initialize state, and the last thing I did was comment code. By then, I didn't feel comfortable deleting it, so I just flubbed the purpose.
I will definitely use the predefined states for my state machine next time.
I am personally very comfortable with this design pattern, although I realize it does not necessarily fit one designated by NI. Is it unwise to use user event driven queues to influence my state machine without actually wiring the queued data to the case selector?
Again, thank you for the review! I will take all of your recommendations and utilize them on my next practice CLD!
-Kyle
I'm somewhat scatterbrained, so making the states match up with the main topics really helps me to stay organized. Sometimes a step doesn't make sense to keep separate from the one after it, so I combined the two steps into one and noted that the empty case was deprecated and no longer in use. SubVIs kept me organized because they roughly corresponded to a paragraph each. This kept the block diagram nice and tidy.
I don't think it's unwise to use a non-standard pattern - at least in real life - although I will say that the standard patterns are standard for a reason. You don't want to make the grader scratch their head over this one. Use an easily recognizable pattern. I do think the grader will frown at the way you used the event structure.
It's funny - most people dop the error handling last. For me, it's one of the FIRST things that I do. It makes it very easy to figure out where your coding mistakes are. 😉 You don't really need shift registers on your error wires because you should have error handling at the back end of each loop. For the purposes of the exam, I think that exiting in an orderly fashion on any error is good enough to show them that you understand how to handle errors.
When I was practicing for my exam, I was unemployed, so my job was to practice once through every day, with a self-review afterwards. It gives a good idea of your strengths and weaknesses.
I think the best advice I can give you is to practice until it gets boring. I chose one design pattern for all the examples, simply to give me a familiar starting place. It came in handy at exam time because I didn't have to panic about how I was going to approach the project. I just started out setting things up and it was calming because it felt so familiar. By the time it came to the unique stuff, I was in a state of mind where I was ready to tackle the project. By the time I was done studying, I knew my stregths and weaknesses so well that I predicted my score to 1/2 point. 😉
When are you going to take it?
