Interview Questions

[USar]

I will be interviewing soon for a LabVIEW/Test Stand position for our team. I am looking for technical questions/exercises to evaluate their programming level. Any suggestions? How do you guys weed out weak candidates?

Thanks.

[tbob]

One thing to do is to show some simple code and ask for an explanation of how it works.  Make the code relevent to your work.

[JackDunaway]

I'm generally a big Spolsky fan. See what he has to say about interviewing in The Guerrilla Guide to Interviewing (version 3.0).

[Broken_Arrow]

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USar wrote:

How do you guys weed out weak candidates?

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By separating the "users" from the developers. On the other hand, you have to be careful not to discredit a strong candidate just because he/she hasn't used your exact hardware interface. A programmer with several years experience who has never used, for example, SCXI, would easily pick it up and understand it if they have used almost any other type of NI hardware.

I would look for red flags by using questions that set up a conversational tone. Here's some examples:

What are some disadvantages of Global Variables?

(Look for at least one of the following: Hard to follow code. Can violate LabVIEW dataflow. Can cause race conditions. Memory issues.)

 

Do you have any experience using Queues and/or Notifiers, and if so, for what?

(If they have not used these, or have minimal experience with them, it may be indicative of a lack of multiple-loop experience, or worse, an over-reliance on local variables). 

Can you describe some programming architectures you have used in LabVIEW?

(Look for keywords like Master/Slave, Producer/Consumer, State Machine, Event Structure, Queued State "Handler", etc. It would be a red flag if they don't know what you mean by "architecture").

 

Are you familiar with MAX? (If they don’t know what you mean by MAX, say “Measurement and Automation Explorer”).

(If they haven't used MAX, it's doubtful they have done a lot of hardware interfacing).

  

Do you use Projects in LabVIEW?

("no" would be a red flag if you require them to use LabVIEW 8.x onward. It's doubtful they have built programs if they don't use Project, and it may indicate that they are not organized). 

Let us know if you need any clarifications. Good luck!

[PaulG.]

Most companies worth their salt will want to see some of your code or even have you write some for them during the interview. Be prepared.

[Ray.R]

Ask them if they use Stacked Sequence Structures and Local Variables.  Thise two are what we have to fix the most from novice programmers.

Take a look at bad programming examples in the Rube Golberg thread.

If the person claims to be an expert, ask to explain what was posted here http://forums.ni.com/ni/board/message?board.id=BreakPoint&thread.id=12320

Message Edited by Ray.R on 05-04-2010 08:40 AM

[smercurio_fc]

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Ray.R wrote:

Ask them if they use Stacked Sequence Structures and Local Variables.  Thise two are what we have to fix the most from novice programmers.

Take a look at bad programming examples in the Rube Golberg thread.

If the person claims to be an expert, ask to explain what was posted here http://forums.ni.com/ni/board/message?board.id=BreakPoint&thread.id=12320

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Well, I claim to be an expert at times (when it suits me), and I have to admit I didn't know about the 0 and -0 distinction primarily because (a) I use LV 8.2, and entering -0 in a control still displays it as zero; and (b) I didn't think that the comparison would ignore a negative sign just because it's in front of a zero. I mean, would that need to be a special rule, or something? 

As for the OP's query: At my previous job we asked folks to write code. Nothing really complicated, but enough to verify that they could. A couple of job interviews I was on in the past I was asked to write code. One time it was to write a simply VI to control set a power supply voltage and monitor the current. It was trivial, but I knew the point was to find out if I could actually walk the walk instead of just talking the talk. This position was in a lab controlling equipment, so it the code was applicable to the job.

[Ray.R]

I forgot the smily face 😉  (I didn't know about the -0 either) 

Another smiley face 🙂  😉  You could read this article  http://www.forbes.com/2010/05/03/how-to-unmask-a-liar-entrepreneurs-management-liar_slide.html

[RayFarmer]

Hi USar,

You want to ask them questions that's going to show that they have a good understand of both LabVIEW and TestStand that fit the needs of your requirement and to be able to develop (that's if its a permanent position) and if it a contract position, then that person should be up and running straight away, without having to look in the manuals to try find out how to do things.

You need to make sure they understand the ProcessModel, test them on the Callbacks that you would use to override in your client SequenceFile.

You need to make sure they know how to interface LabVIEW with TestStand.

If they know about the TS API and have used it within LabVIEW Code Module even better.

If part of the task is creating/managing Step Types, then you need to test they knowledge on this.

See if they have done any parallel executions/threads with sequences and Steps. This will show up their skill level.

With LabVIEW, unless you require them to create/modified/manage your UI then not being able to create EXE is not important, you dont use them in TestStand. Having 2 or 3 years solid experience is what's important. If they know how to use ActiveX then excellent.

Hope this helps

Regards

Ray

[MattBradley]

Ask them what their username is on the NI forum and look them up.  Doesn't necessarily prove they're no good, but could give you an indication as to their skill level.

Also, find out if they are certified.