GPIB drivers running simultaneously in a sub-vi ??

[THN]

I've put all read data functions into the same while loop. And i'm not thinking in adding more frames, 3 are good, 1st one to initialize all 4 instruments, 2nd frame to setup them and the 3rd and last frame will be to read only and probably for some data analizing like graphs of tables.

What you think about it?

Thanks.

[smercurio_fc]

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THN wrote:

 The GPIB/USB that i use, wires to the 1st instrument, but i have all 4 instruments wired in serie. So, i'm communicating with all of them simultaneously, right?

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No. As Dennis pointed out, you can only talk to one instrument at a time over the GPIB bus. This is a limitation with the GPIB bus, not with LabVIEW. Thus, it makes no sense to try to run VIs in parallel since they won't. It's better to simply wire them in a chain using the error cluster. When you do this you have no need of sequence frames since the error wire will dictate execution order. 

[THN]

And can i had a time delay in the between of setup and read? Can you edit my VI with 1 little example showing how should i do it?

Many thanks.

[smercurio_fc · Accepted solution]

Yes, you can include a delay. And, as Dennis indicated the timed loop is not necessary.

I can't edit your VI because I don't have those instrument driver VIs, so I can't wire it up. Instead, I wrote an example using the 34401 drivers that ship with LabVIEW to act in place of the two instruments you have. See attached VI. Replace VIs with your instrument driver VIs.

[THN]

Ok, i got your point, thanks for the help. This will work.

🙂

[THN]

Yesterday when i got your reply, i wasn't able to test it, i only doing it today. And it seems, it's not doing the loop. I need to read the all data continuously, and at least from the test of the VI you did to me, it is only making 1 single reading. Any clue why is that happening, since it is in a loop, it should be reading data till i stop it, right?

Thanks once more for the help smercurio_fc.

[smercurio_fc]

The VI I sent you will run continuously unless an error occurs, or you press the Stop button. I would guess that you are either getting an error (and not displaying it), or you changed the mechanical action of the Stop button.

[Dennis_Knutson]

Or you are simply getting the same reading over and over again. What are you doing that would cause the two measurements to change?

Message Edited by Dennis Knutson on 07-16-2009 10:42 AM

[THN]

Let me see if i can explain, all instruments will have to read in real time, which i think the while loop is ok. So, this will work, but know i need something different, i need to know how to divide the ramp process.

The temperature controller will work as a ramp and as a step. In the ramp form, i will need to divide it by segments, for example: from 200K to 300K i have to define 1 setpoint and 1 rate for the ramp. After it reachs that max. temperature, it have to make a delay to achive some stability. After this delay, it will run another segment, from 350k till 500k. What's the best way to make it?

I will had a wrong VI example that i made, just to show more or less what i want.

Thanks for the support.

[THN]

Dennis, i've changed the multimeter range to the lowest and it detects some oscilations with it. So, it's probably some error like

smercurio_fc said. I can't say the same from the temperature controller because it does not detect any since i'm testing it without the sensor.

Please, check my previous reply, i need help with the ramp structure.

Thanks both . 🙂