How to set up SIT playback

[smithd]

Hey Bladhart,

The Vxworks 9074 works just fine, but since our pxi controllers use pharlap I wouln't be surprised to see similar behavior to what I saw with our 9004--but that doesn't explain why it still doesn't work. I'm currently looking into this issue, but in the meantime I wondered what your overall goal for this system is. Do you just want to run your model with some inputs, or are you looking for more, further down the line?

Thanks,

[Bladhart]

Hello Dan,

My model is an engine model. So, what I need in the end is to be able to change the inputs (rail pressures, fueling demand, etc.) as if it is doing a drive cycle. Start at idle, and ramp fueling up and down in a repeatable way. I may have a few of these pre-defined cycles to simulate different driving patterns.

[smithd]

Hey,

So, I hadn't realized you were using a PXI chassis until you just said so, and apparently it makes a difference. I suppose there are slightly different versions of pharlap from my 9004 to my 8108, but I now see the same problem you see. I will keep you up to date on my progress as far as figuring out what is going on.

As to your overall problem, the reason I asked is that I wanted to mention veristand, if it were appropriate (which I believe it is). Obviously I will keep working to figure out what the problem is with the file playback, but veristand is a pretty cool configuration based program which is intended for hardware in the loop and model in the loop testing. Again, I will continue to work towards a solution for you, but if you are interested in using veristand for future development, you can find out more here: http://zone.ni.com/devzone/cda/tut/p/id/9347

Thanks,

[Bladhart]

Hello Dan,

I still would like to figure out why isn't this working though. Thanks.

[smithd · Accepted solution]

Got it--I don't know why this is happening, but sit should generate a folder called xxxx replay config, like so for the sinewave example: C:\Users\xxx\Desktop\sitforum\sinewave_nidll_rtw\sinewave Replay Configs\, which contains an ini file which looks like this:

[SIT_Replay_Settings]
.....

Filename = "/C/Users/xxx/Desktop/sit/1.tdms"

.....

Now, for some reason, the scripted code for the PXI system takes that entire filename and appends that to c:\ni-rt\system, making the path it is looking for "c:\ni-rt\system/C/Users/xxx/Desktop/sit/1.tdms"...obviously, nobody can find that path.

So, to correct it, remove that path from the Filename item and set it like so:

Filename = "1.tdms"

I have no idea why this is happening or, to be honest, how I found the VI where that problem occurs, but those are questions for another day.

Thanks,

[Bladhart]

Hello Dan,

I tested it out, and it worked. However, it is not that simple. 

Let's say go to the SIT manager, and I am going to use a new book1.tdms for playback. book1.tdms does not exist on the target yet. In this case, when I load the VI onto my target, it loads book1.tdms onto the target at the same time. In order for LV to load the book1.tdms onto the target, the config.ini file needs to have the correct path to book1.tdms on the desktop. If we change out the .ini file before book1.tdms is loaded onto the target, book1.tdms will never get loaded. Thus, my VI still won't file the file.

So, what I had to do was to manually load book1.tdms onto the target first, then change the ini file, then run the VI.

[smithd]

Hey Bladhart,

That makes sense, now that you mention it. I already had the TDMS file on the target, so it didn't argue with me with I changed the config file and pressed run, but that could certainly cause problems. I've already filed corrective action request #301408 for this problem, which goes to R&D for further investigation. Because of the difficulties you faced, even once we knew what the problem was, I am looking into creating a knowledgebase article for this issue.

I apologize for all the difficulties you've had with this product, and I hope that it is relatively smooth from here. To help alleviate the problems you faced with getting the file over, I would suggest that you add a VI like this ( http://zone.ni.com/devzone/cda/epd/p/id/2537 ) to your sit code, and set it up to automatically FTP the correct file over. Obviously this is not an ideal solution, but it should work.

Thanks,