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Having Trouble with VISAs

The type of device I believe is irrelevant, but it is an oscilloscope, funciton generator and a power supply that I've tried. I get the same error regardless of device i hook up, which is either through GPIB or a straight up USB connection. Maybe I'll have to try reinstalling it.

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Message 11 of 22
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@DonutLord wrote:

The type of device I believe is irrelevant, but it is an oscilloscope, funciton generator and a power supply that I've tried. I get the same error regardless of device i hook up, which is either through GPIB or a straight up USB connection. Maybe I'll have to try reinstalling it.


Actually the knowing what device you are using is very relevant.

 

As I have found using a LeCroy Oscilloscope.

 

This works:

Lecroy2.PNG

 

This does not:

Lecroy1.PNG

 

But inside LCWAVE WRITE there is nothing but a VISA Write: 

Lecroy3.PNG

I don't know what kind of secret sauce LeCroy puts in their VISA Write but their oscilloscopes only work with with their vi's.

SCPI commands using the VISA Write on the LabVIEW palette always fail.

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=== Engineer Ambiguously ===
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Message 12 of 22
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Ah well all of my equipment is Agilent.

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Message 13 of 22
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There is a difference.  You can see if if you look closely at the icons on the VISA Write VI's.

 

The one in their subVI does not have a watch at the upper right.  The one in you VI does.  The one with the watch is set for Asynchronous mode.  The one without is set for Synchronous mode.  You can change it if your right click on the VISA Write function.

 

I don't know why that would cause the error message you are seeing about insufficient information finding the device.  Unless perhaps a behind the scenes query to see if the device exists takes longer than normal, and putting it into Synchronous mode gives it just enough time for the device to respond.

Message 14 of 22
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OT@ RTSLVU

Look at those VISA writes a bit closer.... See the clock glyph? LeCroy never implemented Async calls well.

 

That's what I get for playing with the driver and going through old notes.  Raven's fan beats me to the punch.


"Should be" isn't "Is" -Jay
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Message 15 of 22
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@RavensFan wrote:

There is a difference.  You can see if if you look closely at the icons on the VISA Write VI's.

 

The one in their subVI does not have a watch at the upper right.  The one in you VI does.  The one with the watch is set for Asynchronous mode.  The one without is set for Synchronous mode.  You can change it if your right click on the VISA Write function.

 

I don't know why that would cause the error message you are seeing about insufficient information finding the device.  Unless perhaps a behind the scenes query to see if the device exists takes longer than normal, and putting it into Synchronous mode gives it just enough time for the device to respond.


 

Doh! Thanks, you just figured out something that neither NI, or LeCroy could figure out!

 

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=== Engineer Ambiguously ===
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Message 16 of 22
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@DonutLord wrote:

Ah I'm not sure about the serial drivers. However i am using labview 2016 64bit and have NI-VISA drivers 16.0. I would assume they are compatible as they are the latest versions of each.


I guess you need to install also NI Serial drivers. If you've installed NI VISA from NI Device Drivers pack, then it is included there by default. But if you've installed NI VISA separately, there are chances, that NI Serial drivers are missing now on your machine.

But, it does not explain the fact, that you could run code via VISA express VIs...

 

logos_middle.jpg

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Message 17 of 22
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@kosist90 wrote:

@DonutLord wrote:

Ah I'm not sure about the serial drivers. However i am using labview 2016 64bit and have NI-VISA drivers 16.0. I would assume they are compatible as they are the latest versions of each.


I guess you need to install also NI Serial drivers. If you've installed NI VISA from NI Device Drivers pack, then it is included there by default. But if you've installed NI VISA separately, there are chances, that NI Serial drivers are missing now on your machine.

But, it does not explain the fact, that you could run code via VISA express VIs...

 

 


You only need to install NI-Serial drivers if you are using a serial device that is made by NI.  If you are using something already built into your PC, or some other companies add-on, you would have probably installed drivers made by that company.  In which case you only need to have NI-VISA installed.

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Message 18 of 22
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I'll look into the serial drivers.

 

also actually discovered that the express vi only works when testing it, once I put it on the block diagram and it generates code it doesn't work and gives the same error.

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Message 19 of 22
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It won't work.  Because the underlying code that that the Instrument Assistant generates also uses the Asynchronous mode of the VISA functions.

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Message 20 of 22
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