CLAD Exam

[guangdew1]

Hi everyone. I'm going to take the CLAD exam in two weeks. There are things I couldn't figure out and I'd like to discuss with someone who are also going to take the exam or interested in it, or I may be able to answer some of your questions. My email is : guangdew1@yahoo.com and you can contact me by email so we can discuss over some difficult or confusing things.

Best regards,

Guangde Wang

[smercurio_fc]

Why don't you just post your questions on here?

[guangdew1]

Thank you for your response. I read some of the related posts, people responded in different ways. Afterwards, I still don't know the right answer. Any way, I'll post this question.

Which of the following only plots data in evenly distributed intervals along the x-axis?

A	Waveform Graph
B	Waveform Chart
C	XY Graph
D	Both A. and B.
E	Both B. and C.

In the question, my understanding is that evenly distributed means we can not set log or alike scales. If this is true, I see only Waveform Chart can not be set log scale. The other two can be set log scales. So the answer is B, is it correct? Anyone can give some advice?

Guangde

[smercurio_fc]

Well, regardless of what others may or may not have said, from the LabVIEW Help:

LabVIEW includes the following types of graphs and charts:

• Waveform Graphs and Charts—Display data typically acquired at a constant rate.
• XY Graphs—Display data acquired at a non-constant rate and data for multivalued functions.

And further down ...

Waveform Graphs and Charts

LabVIEW includes the waveform graph and chart to display data typically acquired at a constant rate.

Waveform Graphs

The waveform graph displays one or more plots of evenly sampled measurements. The waveform graph plots only single-valued functions, as in y = f(x), with points evenly distributed along the x-axis, such as acquired time-varying waveforms. The following figure shows an example of a waveform graph.

...

Waveform Charts

The waveform chart is a special type of numeric indicator that displays one or more plots of data typically acquired at a constant rate. The following figure shows an example of a waveform chart.

...

XY Graphs

The XY graph is a general-purpose, Cartesian graphing object that plots multivalued functions, such as circular shapes or waveforms with a varying time base. The XY graph displays any set of points, evenly sampled or not.

So I think you can pretty much answer the question given that.


Message Edited by smercurio_fc on 04-30-2008 05:15 PM

[guangdew1]

Thank you for your response. I think I can understand now what it means.

I'm struggling with the following question too. I will post again to make my reasonings and please let me know about your opinion.

Guangde

18) What VI is typically used to terminate an Error Cluster wire and to display any error message?

A   Merge Errors 

B   Simple Error Handler 

C   One Button Dialog/Two Button Dialog 

D   Generate Front Panel Activity 

[dan_u]

The question already holds part of the answer: display error message. So it must be a VI that can show a dialog. Also, it must have an error cluster input. These 2 facts leave only 1 answer...

[smercurio_fc]

Your questions are pretty basic. Did you go through the LabVIEW courses? These kinds of questions are typically covered in those courses. You can also take the online courses for free.

[guangdew1]

Hi Dan_u,

Thank you for your response to my question. I think I understand it now. The following is another question I found online that I feel puzzled. People say the correct answer is A, I know the other three are not correct. What I don't understand is how two events can occur at the same time for a state machine. I used state machine myself and I like it, I think it will execute one state at a time. I couldn't think of any scenario that two states occur at the same time. Please advice, or better if you can provide an example to show it.

Best regards,

Guangde 

16) What is one disadvantage of using the State Machine VI architecture?

A   If two events occur at the same time, only the first event will be handled and the second will be lost.
B   The diagram becomes significantly larger when changing from a General VI to a State Machine VI.
C   State Machines cannot acquire data or use DAQ functions.
D   A State Machine VI can only traverse states in order.

[dan_u]

You're right, a state machine can only execute one state at a time. That's exactly what answer A says.
Usually you have some conditions in a state that decide what state will be next. Now if 2 conditions would be met you would have to go to 2 states. This isn't possible. Of course there's ways to implement such behaviour (queues for instance), but a standard state machine doesn't have a memory (queue) of what should be done.

Hope this helps
Daniel

[smercurio_fc]

At best, the question is poorly worded, since it's mixing "events" and "states". A state machine executes states, not events. Events trigger the movement from one state to another. It is also worded based on assuming that it's referring to the enum-based state machine architecture shown in this KB article, and most seasoned programmers use a queue rather than an enum anyway, as Dan alluded to.