Using LabVIEW for temperature control with AMREL SPS200-50-A022 power supply

[DinhT]

OK, I created the control on the top VI. Thanks. I didn't know how to do that before. I am still getting the same error in the top level VI and a different error in the Initialize VI. I've done as before and attached them.

In case you don't see it, here's the error from the top VI:

VISA Read in ARSPS Initialize_mod.vi->Tfeedbackpowercontroller-nolvdt-Dinh.vi

Error -1073807339 occurred at VISA Read in ARSPS Initialize_mod.vi->Tfeedbackpowercontroller-nolvdt-Dinh.vi
Possible reason(s):
VISA:  (Hex 0xBFFF0015) Timeout expired before operation completed.

Here's the error in the Initialize VI:

ARSPS Initialize

Error -1223 occurred at ARSPS Initialize
Possible reason(s):
LabVIEW:  Instrument identification query failed.

Hex Code: FFFFFB39

Thanks again.

[Dennis_Knutson]

I don't see how you can be getting two different error codes from the same VI. Don't bother to run your top level at all until you get the initialize function, all by itself, to run. You also haven't created the indicator on the output of the VISA Read after the *IDN? command is sent. Then we will see if you are not getting the correct response or if you are still getting the timeout. If you are really getting the timeout, then you will have to do a bit of troubleshooting. The VI I modified uses a line feed constant as a termination character. Check the instrument manual if that is correct.

[Coq_Rouge]

Hi Dinht

I fear you are running around in circles. Before you can do any serial communication the serial settings and the cable has to be 100% percent correct. Are you sure about this? So please take a step back and go back to basic. Use the VI "Basic Serial Write and Read.vi" I sent you. Type in the serial settings and correct the "string to write" to *IDN?\n Then you get something back from this request your serial settings are correct. Only at this point you can move on with your project. I have also noticed that you have a small flaw in you programming. This may cause your -1223 error. It is in the while loop searching for instrument ID string. I have also noticed after sending the *IDN? Command you wait for 50 bytes. Are you sure this is the correct number of bytes that is sent back from your instrument. You may check this with the "Basic Serial Write and read.vi"

Also notice that implementing the solution from Dennis regarding the term char. Your instrument will receive two LF char (\n) at the end of the instrument commands. This is true for most of the commands sent from the "Modded (ARSPS Application Function) nostopping.vi". One LF is inserted by Visa and one by the functions in the instrument drivers. I do not know if this will cause any problem for the instrument. But it is worth paying some thoughts.

If you have any luck in receiving a response from the "Basic Serial Write and read.vi" please post a screen shot

 

[Dennis_Knutson]

I never noticed that some of the subVIs have a termination character in the command passed to the VISA Write. The init and reset don't and there is also a function to change the EOS. If you use this, then I would expect the init and reset functions to stop working. If you use the SET EOS function to change the EOS to CR, since the functions are hardwired to append LF, then those functions would stop working. Strange. Since any GPIB instrument designed in the last 20 years is not supposed to use CR or LF, it makes things even stranger. The whole ide of using the property node to set a termination character was to avoid modifying a whole bunch of subVIs to add the correct termination character. You may have to do this anyway.

[Coq_Rouge]

No problem at all Dennis. I just thought it was worth mentioning. My guess is that it doesn't matter at all. They are probably struggling to get past the errors in the "ARSPS Initialize_mod.vi". And as I have pointed out mode in my last post. They should investigate number of bytes received after the IDN command, and the programming flaw causing the -1223 error. And of course be 100% certain they have correct communication settings and cabling. These people are just struggling like students sometimes do.  

[Dennis_Knutson]

You were right to mention it. I think the problems started with the instrument vendor and the author of the driver.

The number of bytes received with the *IDN? should be the same as with a GPIB instrument but of course, this might be something else that's not quite standard.

In an earlier post, the op did say that Hyperterminal and the Basic Write and Read was working so it might be just a matter of having the correct string to parse in the initialize function.

[Coq_Rouge]

Well the funny thing is that the vendor has a newer labview driver. In my first posting in this thread I wrote down a Google phrase I tested. And yes a newer driver came up as hit number 3. Anyway I do like to help students. But not solving theier project. But for now I STRONGLY recomend them keep the current instrument driver and focus on the topics mentioned in my last postings

Message Edited by t06afre on 01-23-2009 11:13 PM