Parrallel vi's with Visa

I'm trying to create a parrallel vi with two DMMs (Digital Multimeters) making voltage and current measurments using a Visa example provided by Agilent. I thought the vi was parrallel that I wrote but when it executes it sets ups both DMM's then proceeds to gather measurments from the first DMM, then the second DMM. Is there a way to get readings from both DMM's in parrarel? I was initally using one DMM but the setup from going to current and voltage was taking too much time. I suspect I have a dependancy that I'm not aware of between the two portions of code.
Regards,
-L4Y
Attachments:
Agilent 34401 Current Voltage Measurement.vi ‏21 KB

I assume one DMM will measure voltage and the other DMM current (directly or across a shut).
You wish to instantaneously or simultaneously measure both voltage and current to get a good power calculation.
But you wish to do this over time with readings at a rate around 100 samples a second (200 per second counting both volts and current)
That going to be tight, but you might get close but you will have to take complete control of the DMMs bypassing the driver VI that you are using.
You could setup the dmm to take all the readings and store them in it’s internal buffer and then collect the readings at the end. But the internal buffer has a limited size.
Look at bus trigger to get the two dmm to take their read at the same instance
Turn off the front display to speed up readings
Adjust your resolution to speed up reading
Turn off auto ranging to speed up reading
The manual has a section on what effects the 34401 reading speed.
Get the manual and read up on SCPI commands
You could use the GPIB 488.2 commands from the pre VISA days. Look at communicating to your dmms using the commands in the GPIB 488.2 pallet. There you can broadcast your commands to more than one device (see SendList) at the same time. But you still have to read back from each one at a time.
Using a power meter might be your best option.
Lunch break is over and I have to get be to my job, but might look for some old code where I had to take fast readings using a dmm.
Omar

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Problem on WinXP / Labview 6.1 with VISA (serial port)

There is a problem on WinXP / Labview 6.1 with VISA which i use to poll the state lines of the serial port. The only functions that i use are "VISA Open", "Find Resource", line state properties and "VISA close".
On my own machine (WinME) it works fine as a standalone application (with runtime engine in the same direction), even if i rename the Labview directory so that Labview is not found.
From my VXIpnp directory i deleted all but these files:
directory "Win95",
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Hey Joachim,
In order to create an installer that includes the VISA Run-time engine for serial IO you will have to purchase LabVIEW 7.x. See screen shot. This packages a small compact version of the run-time that can only be used for serial, but it takes up much less space. The installer that I created has my application, the LV Run-time, and the VISA run-time and it is about 26 MB.
That is much smaller than if I had to include the 32 MB LV 7.1 run-time and the 14 MB VISA run-time separately. It would have been even smaller if I would have uncheck some of the items that I wasn't using.
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advanced.JPG ‏31 KB

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Hi,
I've successfully setup both LVDiff and LVMerge with TortoiseSVN and I'm using it heavily, but I get an error from LVDiff if the VI belongs to a library:
Error 1004 occurred at Open VI Reference in NI_procmphier.lvlib:CMP compare two VIs.vi->lvdiff.viPossible reason(s): LabVIEW: The VI is not in memory.
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I just had the same problem, strange that no one has seen it before...
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We are using devices like PXIe-6363, PCIe-6321 depending on requirements and these are dealt with using the MHDDK with Visa backend on Windows (I hope that is the correct terminology).
All I/O, both analog and digital simultaneously, is done using DMA transfers using the standard MHDDK classes for doing so. This all works without problems.
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You'll have better luck posting to the ddk board - http://forums.ni.com/t5/Driver-Development-Kit-DDK/bd-p/90

Play sound in specified duration and desired file when reading data with VISA functions ?

Hi.
I read data with VISA read function and then I use functions like multiple for showing data on Chart. every thing is OK.
now I want play a specified sound (like a 3s song in my desired folder) when signal amplitude cross over from specified value. then after desired time, it will be wait for new cross over from specified value and this procedure repeat again until I stop the program.
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I use this VI for reading data and mentioned part which is sound part is empty and I don't know what I must done ?
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Thanks.
Solved!
Go to Solution.

I would recommend making the data type of the notifier a cluster that contains a path and a numeric (double). The path tells the player which file to play. The numeric is the duration.
Now for a slightly complicated, but really neat, way to stop your second loop. Do not use a second notifier. Instead, send the normal notification but use Not A Path for the path in the cluster. Your second loop can do a check for the Not A Path and stop when that is recieved.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions
Unofficial Forum Rules and Guidelines

Memory leak with Visa Close in loop

I read the other posts about the memory leak problems with Visa Close, but eliminating the Visa Close from VI causes problems with read & write (it seems to go out of sync). Any suggestions? Example attached.
Attachments:
MKS_651C_Serial_Communication.vi ‏144 KB

Solved the problem. I had to change the bit count and adjust sort. Removing the Visa Close did eliminate the memory leak.

Problem with visa 3.2

Hi all,
We have a problem with an application (LV7.1 / WXP) which has to decode serial data from a smart actuator. This actuator sends 8 bytes of data @38400 bps every 3ms (which leaves about 1ms interval between these blocks of data). The application is working perfectly with VISA 2.60 but since we tried it with VISA 3.20, we are constantly getting framing and I/O errors.
We are sure that the problem is coming from VISA, as we ran the software on the same PC with 2.60 and 3.20. The errors come only with 3.20.
An application engineer of NI told us that these errors were not implemented in the 2.60 version and that's why they didn't show up. However, the data that were read by the software with 2.60 were absolutely consistent (no garbage) ! If we filter these errors out, many data are lost, so this is not a solution.
The problems come either in development mode or with an executable file.
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If it can help, we can provide a NI-Spy capture file.
Thanks to anyone who can give us some advice on this topic !

Hi Kaustubh,
Yes, either a Spy capture or some specific error codes would be great to continue troubleshooting this issue. Without more specifics, it is hard to say what errors that VISA 3.2 is catching that 2.6 did not. Hopefully we can help you further once a spy capture is posted.
Alternatively, if VISA 3.2 does catch some errors that did not harm your original program, or even errors that your original program depended upon, you could always go back to the previous version and use that one. Just wanted to be sure you were aware of that option.
john m
Applications Engineer

What i need to write when i buy with VISA - ( country - ? AAO? or .... ) in Kazakhstan ????

What i need to write when i buy with VISA - ( country - ? AAO? or .... ) in Kazakhstan ????

Well, then your question is a different one: "What do I need to make a web application with ERP data".
In NetWeaver everything is contained that you need technology wise, but no business applications (almost, there is a grey zone coming from the ABAP world).
If you want to access also business data there are two ways:
1. You can access existing R/3 environments from there via RFC and BAPI
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Regards,
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How to read three parameters for exemple temperature,current and voltage from the same port with visa read and separate them in a table

Hi i want to read parameters with visa read, from three sensors related to pic16f877a, using module xbee ..but i want to make every one from those parameters (temperature, voltage and current) in a table ..it's the first time i use Labview so i don't know if ther is a solution for my problem so if any one have any idea please help me. thnx in advance.

[email protected] wrote:
Hi i want to read parameters with visa read, from three sensors related to pic16f877a, using module xbee ..but i want to make every one from those parameters (temperature, voltage and current) in a table ..it's the first time i use Labview so i don't know if ther is a solution for my problem so if any one have any idea please help me. thnx in advance.
The short answer is: "Yes, of course." But you are going to have to do the legwork and learn LabVIEW basics before we can offer meaningful help.
Bill
(Mid-Level minion.)
My support system ensures that I don't look totally incompetent.
Proud to say that I've progressed beyond knowing just enough to be dangerous. I now know enough to know that I have no clue about anything at all.

Accessing Parallel Port Control and Status Registers with VISA and Win7x64

Hello all,
I've posted this in the I/O forum for VISA, but this main forum seems to get a lot more traffic so I'm posting here too.
Wondering if anyone has a solution for accessing the Control and Status registers on a parallel port with VISA, now that Win7 has locked down the I/O ports and In Port.vi and Out Port.vi don't work anymore. I've been looking all over for a solution and haven't found anything that will help; either the VISA solution is shown but doesn't mention if the Status and Control registers are accessible, or the solution is for a 32 bit system.
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Basically what I need to do is use the data lines to send info, and watch the status lines for incoming discrete signals. Since parallel ports are half duplex, I can't have the data lines be both inputs and outputs simultaneously, which is what I need. A cheap D I/O card would be the easiest solution, but to make a long story short I'm dealing with a legacy system and that's something my higher-ups want to avoid.
Any help is greatly appreciated!

Hello,
I was able to solve this problem using software from Entech Taiwan; it's called TVicPort and it's available for free for personal use, and very cheaply for commercial license. If you have questions let me know, I'll do my best to answer them but investigate Entech's solution and see if it'll work for you:
http://www.entechtaiwan.com/
http://www.entechtaiwan.com/dev/port/index.shtm

Serial port: from 6i without visa to 7express with visa ?????

upgrading from NT4 6i max 2.5 to 2000 7exp max3.1 my pzt on PC serial port do not move anymore. The DA converter do not understand the instructions.
Running max on the coms: done OK
Looping back the visa instructions: done instructions OK
Trying hyperterminal: done OK (the DAC move)
the coms are in function but the DAC do not move while driving with visa...any suggestion??

I also upgraded from LV6.1 to LV7 and use serial communication. I now use VISA (and prefer it). However, for the older functions.. they should work..
Have you looked into the VISA Advanced controls under Interface Specific and under "Serial". You may find the functions you need to "upgrade" your serial comm vi's.
-JLV-

Static VI with Visa serial functions is very slow to display front panel

THere is a delay time of about 10-20 seconds to "display" the first VI's front panel that has Visa serial functions in the source code.
All works fine after the first load but the initial delay of the front panel load makes it look like the PC could hang during this time. AFter this other VI's load immediately with no delay. I am concerned because I do not want to have to load a VI manually every time I start the APP which is the only workaround I can do at this time.
Im wondering if anyone else has seen this kind of behaviour.
I do not remember this happening until I upgraded my APP to LV7.
DEll optiplex GX260 with 500MB RAM, Win2k and using N.I PCI-232-16 card w/ LV7 now.
Attachments:
RECV_LOOP.vi ‏55 KB

I would like to resurrect this thread, as I am having the same problem. The problem stems from the VISA resource control on my front panel, because I have many COM ports registered on my system. The last suggestion from Scott B. was to "post the resulting .SPY file and I'll take a look at it". So, here is my .SPY file, and as you can see, it takes far too long. As many of these COM ports were registerd from USB converters, most of them are not actually present at this time on the system. However, even the ports that ARE present take a long time to register (i.e. COM1 is present and shows 3 seconds to register). These COM ports shown in my VISA resource do not correspond to those shown in my Device Manager, nor do they correspond to those shown in MAX under Devices and Interfaces.
I am using LV 7.0 on WinXP SP2, with VISA version 3.2.
OK, I just discovered something that mostly cured the delay. When I was getting the VISA version number just now, from MAX in the Software>NI-VISA item, there is a tab "VISA Options", and another tree structure in the middle pane. Selecting "General Settings>Aliases", there was a list of the old COM ports, so I cleared this list and then re-started MAX, checked again, and now only the COM ports shown in "Devices and Interfaces" matched this list (which still doesn't match my Device Manager, but no matter). When I re-opened the LabVIEW FP, it opened quickly, and the ports listed in the VISA resource matched those I saw in MAX.
At any rate, although I just cured the symptom, the original problem of old aliases in VISA causing unacceptable delay should be fixed by NI.
David Moerman
TruView Technology Integration Ltd.
P.S. the message poster didn't allow my to post a *.spy extension, so here is the *.zip of it.
Attachments:
Capture.zip ‏2 KB

Documentation for programming a PXI card with VISA in LabVIEW.

Hi,
Where can I find a documentation for programming a PXI card with VISA in
LabVIEW?
Thanks.
Denys.

Dan,
Thank you for your answer, short but useful to start.
Denys.
"Dan Mondrik" a ecrit dans le message news:
[email protected]..
> Denys:
>
> Our NI-VISA documentation for PXI has been somewhat scarce. We are
> improving it in the next version. In the meantime...
>
> Call VISA Find Resources with "PXI?*INSTR" to find all PXI devices.
> Call VISA Open with a device string like "PXI::devicenum::INSTR" or
> "PXI[bus]::devicenum[::function]::INSTR". In LabVIEW, use the VISA
> class "PXI Instr", available since LV 5.0. (The generic "Instr" will
> also work but will also present GPIB and VXI options and may be too
> confusing.)
>
> The property node has all the available PXI properties such as
> BAR0-BAR5 base/s
ize/type, and also manufacturer ID and model code.
> You can use all the register based in/out/peek/poke methods, just make
> sure to use the appropriate address space for your device.
>
> Dan Mondrik
> Senior Software Engineer, NI-VISA
> National Instruments

HT3702 when i purchase with visa card it tell me please contact itunes support to complete this transaction

when i purchase with visa card it tell me please contact itunes support to complete this transaction please help me

Many people are having this same problem. I myself was in touch with iTunes for over a week as well as with my bank (Capital One in this case). For Some reason iTunes has put your debit/credit cards into a "fraud mode". According to my bank representative people have been calling in for about 2 weeks about this, so you and I are not alone at all about this. For me I was able to buy anything as long as it was under $10.00, but anything above gave me the errors you are having. You need to contact your debit/credit card customer service numbers and first make sure that there is no "block" or "cap" on them for iTunes. Then ask them why it is being declined. They may ask you to verrify the city and or state which the iTunes store billing you is in, TELL THEM "CALIFORNIA". Then once you have done everything with the bank you need to contact iTunes Store which is only possible with email (or so Apple has told me), and have them reset the billing and and address information for your account. They will email you back saying that in 30 min...blah blah blah... Basically once they have responded log off from the iTunes store on every single apple device you have: iPhone, iPad, Apple TV, iTunes on your computers, all of them! Then log back in through your COMPUTER and enter all of your information again. This should sove your problem completely. It worked for me.... Good Luck!

HT4990 i have apple id with visa card,but now i dont use visa card and i have my id shoud free help me!

i have apple id with visa card,but now i dont use visa card and i have my id shoud free help me!

You need to ask Apple to reset your security questions. To do this, click here and pick a method; if that page doesn't list one for your country or you're unable to call, fill out and submit this form.
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Parrallel vi's with Visa

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