Drive two modules from a voltage supply N6700

[fabien-g]

Hello,

I use a bit of code to drive 2 modules from a power supply N6700.

When I drive the first one, it is correctly swithed on at 12V but when I drive the second one also at 12V, the first module switches off for a reason I do not understand.

Then I tried the following manipulation :

Step 1: Switch on the first module

Step 2: Switch on the second module

Step 3: Switch on the first module again as it is automatically switched OFF at the step 2

A the step 3, I get the following error:

109	Multicast connections cannot send to singlecast addresses.

I precise that as soon I send a command about the module 2 (such as sending a limit of current for example) the module 1 switches off.

Anyone has a clue?

Thanks,

Fab

[cstorey]

Unless you attach code all we can do is guess. Also, more information would help.  

N6700 = Keysight N6700?

If so are you using the Keysight N6700 LabVIEW driver?  (http://sine.ni.com/apps/utf8/niid_web_display.download_page?p_id_guid=6EEA8B6A8FEC4F05E04400144FB7D2...)

What 2 modules are you using?  What slots are they in?

Give us more info to help you!

[fabien-g]

Hello, I use a power supply N6700C, the four modules I use are

1- N6733C

2- N6733C

3- N6734C

4- N6734C

In the screenshot, you can see I call the vi "Pilotage alim N6700" which called each other subvi.

Regards,

Fabien

[fabien-g]

Hello,

I inform that at the beginning I call the sub vi "Pilotage alim N6700", which called each other sub vi I have forwarded you.

The problem I have is that, after swithing on the first module at 12V, as soon as I try to initialize the supply to send the order for the second module, my first module is switched off.

Best regards,

Fabien

[fabien-g]

Hello,

I forgot to say,

Yes it is a Keysight N6700C that I use.

Regards,

Fabien

[cstorey]

You did not attach the full code, but the screen shot shows alot of sequence structure cases and it doesn't seem to make good use of data flow.  You should read about a state machine architecture.

You are likely initializing communication to the instrument twice in your code, and by default that is reseting the unit and thus disabling the voltage on all units.  Look at the TRUE boolean attached to teh Initialize.VI.

Attached is a very simple VI that sets voltage on 2 channels, and then reads the current of each channel.  Note that the initialize VI is called only once and that the VISA resource is passed to the VIs that configure both units.

[fabien-g]

Hello,

Indeed here is the bit of code I have forgotten to provide.

Using that code, I notice at the first time I have the first power supply correctly activated (validated with multimeter), and after in the code, I open a communication with a scope. I guess the communication with the scope is not correctly closed or maybe I should use a tempo at the initialization as shown in your code "short delay with errors".

I am going to do some test.

Best regards,

Fabien

I have added large tempo to see if it changed something but the code is not working either.

I do not want to activate necessarily the 2 module of the power supply at the same time. It depends of other variable in my program.

Thank you for your help.

[fabien-g]

Hello,

I have used your bit of code to drive the 2 modules at the same time and it works perfectly.

Thank you,

Fabien

[cstorey]

Hi Fabien,

Glad it works!

From what I can gleam of your application you should really look into an Event driven State Machine design pattern.

- https://www.youtube.com/watch?v=RuIN31rSO2k

- http://www.ni.com/white-paper/2926/en/

It will simplify the design significantly.  You would have an initialize state, a close state, an error state, a set voltage/current state, etc.. as required.

Good luck.

Craig