Instrument I/O Assistant and Graphing
Does anyone know how to use data taken from an Instrument I/O Assistant Input and put it into the y values of a graph?? I'm having issues with this because it returns values like "v 0" and "v 256" but I need just the number value to get a graph to work. Any advice would be very much appreciated. Thanks in advance!
Solved!
Go to Solution.
Hi Rach_77,
In order to get rid of the "v ", you can use the String Subset Function and set the offset to 2. This will take away the first two values and just give you the number. From there, you will just have to convert the value to whatever type you would like. I hope this helps!
Kim W.
Applications Engineer
National Instruments
Similar Messages
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A very simple problem...
Very new to LabView, and I am struggling with wiring up my Daq Assistant in order to graph data from a load cell. I've connected my load cell to the Daq and want to measure force readings over a span of time/when I press stop. When I run my program it only graphs a finite number of readings and then erases the graph to copy new readings on top. I put my graph outside of the while loop so that it would graph one reading at a time as they were read but it's not working. If my wiring isn't what's wrong, I have a feeling that my time settings for the Daq Assist are not right (and I don't know how to set those either.) I don't understand the description/effects of Rate and Samples to Read.
Thanks for your help.
Solved!
Go to Solution.
Attachments:
Learning Load Test.vi 61 KBAFLR wrote:
A very simple problem...
Very new to LabView, and I am struggling with wiring up my Daq Assistant in order to graph data from a load cell. I've connected my load cell to the Daq and want to measure force readings over a span of time/when I press stop. When I run my program it only graphs a finite number of readings and then erases the graph to copy new readings on top. I put my graph outside of the while loop so that it would graph one reading at a time as they were read but it's not working. If my wiring isn't what's wrong, I have a feeling that my time settings for the Daq Assist are not right (and I don't know how to set those either.) I don't understand the description/effects of Rate and Samples to Read.
Thanks for your help.
Hi AFLR,
I think settings are fine, you have set DAQ to read 100 samples at the rate of 100samples/second, so you'll get 100 samples every second.
Now in order to retain the previous data in the Graph (which is not the nature of Graph), you may need to preserve it by writing extra code.
If you already know about:
1. Shift registers and
2. Components of Waveform
You can easily implement this requirement, find the attached VI for your reference.
I am not allergic to Kudos, in fact I love Kudos.
Make your LabVIEW experience more CONVENIENT.
Attachments:
Learning Load Test_Modified.vi 79 KB -
I am new to LabView, so please bear with me...
I tried to communicate with an RS485/2-wire device through COM1. I used Instrument I/O Assistant (and Advanced/Basic Serial Write and Read examples) to write command (HEX string) to COM1,
tried writing HEX strings with and withour end bye (is 0D0A the correct end signal for HEX string?). Both didn't get device's responce. Looks like the device didn't recognize the command.
I monitored the transmitted signals on the bus, they were not differential as supposed to be.....
What is the possible reason to cause this? Please help...
The hardware connection is OK, because I am able to communicate with the device through COM1 (with the same command) using different software application.How are you sending the hex? Is your string control set for hex display or normal? If it's set for normal, then if you send something like 'AD', then you aer sending the ASCII characters 'A' and 'D' and that's not the same thing. I don't believe the I/O assistant can send hex but you can modify the basic serial write and read to do so. Just right click on the string control and select 'Hex Display'. You can also enter the data in a numeric control (set for dex display) and use a type cast or an array of U8's and use the Byte Array to String function. Hex data usually doesn't use any kind of termination characters such as CR/LF.
If communication is working with another app, then as you said, the hardware is okay and it's not a problem with differential signaling. -
Instrument I/O Assistant Missing
Hi I am trying to communicate with an oscilloscope through Labwindows CVI by making use of the Instrument I/O Assistant, and on this site it shows how one is able to do that:
http://zone.ni.com/devzone/cda/tut/p/id/4554
However in my tools menu there is no Create Instrument I/O Task option available. I am running version 6.0 could that be the reason? If so any other ways to get around that? And if not any ideas how I can communicate with the oscilloscope through the Instrument I/O Assistant.
Thanks in advanceHello,
It could be that Instrument I/O Assistant was not around in CVI 6.0, be sure that you have NI VISA installed. Are you talking Serial or GPIB to the instrument? You certainly do not need the instrument I/O assistant, you can write the code yourself and start with the VISA examples which cab be found at:
Start >> Programs >> National Instruments >> VISA >> Examples >> C
Have a good weekend!
National Instruments -
Instrument I/O assistant doesn't work, i've installed its driver after labview
I've installed labview 7.1, NI DAQ740CD1 & CD2 and Instrument I/O assistant's driver. But when I open the properties
of Instrument I/O assistant i have an error message which says that i have to installed Labview 7.0 before the Instrument I/O assistant's driver(i've done it). I desinstalled and reinstalled this driver but after the operations, the same message is still here.
i tried to do something else. i've desintalled labview and all the drivers. the Labview installation program prompted me to insert the National Instruments Device Drivers CD. i clicked "cancel" (it's said on the notice) and i've installed the NI 488.2 Driver, the NI DAQmx Base Driver, NI DAQ740CD1 & CD2 and Instrument I/O assistant's driver. I have always the same message. Why ant what can I do??? I need to have the output "TokenName" on the Instrument I/O Assistant and it's not here.Hello,
Which driver have you on your computer ? You can see them in MAX >> Software. Which is version of ni-visa, ni-488.2 ?
What kind of protocol do you want to use : gpib, serial, parallel ?
What ahhpens in AMX when you test your communication ?
What are error code and error string ?
Regards,
Isabelle
Ingénieur d'applications
National Instruments France -
Dear NI creators and users,
I freshly installed the LabVIEW 8.5 and the default set of device drivers (on a new Windows XP machine), all of which I downloaded as disk images from our university central repository (we have a site-wide license). The first thing I tried to place in my first VI was the "Instrument I/O Assistant" and I got this message: "Measurement and Automation Explorer or Instrument I/O Assistant is not installed correctly. Please install these from the LabVIEW Driver CD." I tried to repair the installation, but no change. The M&A Explorer comes up fine, when I select it from the Tools menu, so I doubt, that the problem is there. Needless to say, the "Instrument I/O Assistant" throws the same error when double-clicked in the template file.
Does anybody have a similar or the same experience? What can I do to solve this problem? Perhaps I should add that the computer with LabVIEW is intentionally not connencted to the internet, so in case the solution involves an update, I would very much appreciate some guidance to an off-line update
Many thanks to all for any helpful remarks.
Daniel
Solved!
Go to Solution.Hi Daniel,
the following knowledge base contains some information how to troubleshoot:
http://digital.ni.com/public.nsf/allkb/DC808866AF7D5C0986256FCE006E9BAB?OpenDocument
Maybe you didn't install the NI-VISA or NI-488.2 driver.
I wish you Merry Christmas and a Happy New Year.
With best regards
Ralf N.
Applications Engineering
Germany
PS:
If that wouldn't work for you, download the latest driver-CD from our website and install it. ( It may take a while. )
http://joule.ni.com/nidu/cds/view/p/id/1079/lang/de
I'd recommend to use an USB-harddisk for transferring the files.
Message Edited by ralfn on 12-23-2008 02:29 AM -
Instrument I/O Assistant returning delayed/slow response?
Hi there,
I'm somewhat new to LabVIEW 7.1 - I'm trying to make a simple program that reads and parses data over a serial line then plots it.
I created a small program which connects the output from the IIOA to waveform charts. I've read that the waveform charts plot the data points when the data is received, but when running the program, the chart updates with a new data point at 1Hz, yet my data is being sent at ~10Hz.
I opened the Front Panel for the IIOA and ran just that .vi, and still, the data updates very slowly.
Can someone offer me some insight regarding this problem?
Thank you,
StefanHi Stefan,
If you have opened the front panel for the Instrument I/O Assistant,
and the data still updates slowly, then it is likely that your
instrument is taking longer than you think to respond? I would
recommend that you run NI-SPY while you are performing your
acquisition. In NI-SPY, you can double click on any of the driver
calls and see how long the command took to execute. This will
allow you to determine whether there is a long delay inbetween two
commands, or if the read command is taking a long time to
complete. I suspect that you will see that the read command is
waiting a while before it actually receives the data and is able to
return.
Let us know what you are able to find with NI-SPY, or if you have any more questions.
Jason S.
Applications Engineer
National Instruments -
Instrument i/o assistant always generates async methods for read and write!
I am trying to generate VI by instrument i/o assistant, but it generated 'Visa write' and 'Visa read' always in asynchronous mode. Even if I unchecked asynch boxes in MAX->Visa Test Panel.
I need only synchronous mode! And it is very uncovenient after open front panel change Synchronous I/O Mode from Asynchronous to Synchronous!postoroniy_v wrote:
Asynchronous mode does not work for my hardware.
and before Instrument i/o assistant generate diagram I have possibility to check requests and responses to/from my hardware. in this case everything is fine.
after generate does not work.
Is it possible you don't have a sufficient amount of wait time between a VISA Write and VISA read to give the instrument time to receive the communication and turn around a response? Take a look at Basic Serial Read and Write example VI. If you are using the I/O assistant and checking things manually, it will work because there is no way you can generate a Read too fast. It still would take a fraction of second to generate the write and do whatever clicking to generate the read. -
Instrument I/O assistant isn't installed properly under windows 2000 and xp
after the complete installation of Labview 7express (FDS),the instrument I/O assistant does not work. An error mesage pops up saying that the assistant is not completely installed and that labview 7 should be installed prior to the assistant and that I should reinstall the assistant. I tried to reinstall the I/O assistant directly from the device driver reference CD but it has no effect. What could I do to have the assistant installed correctly ? ( I tried under windows xp same problem)
I forgot the screenshot.
Attachments:
untitled1.gif 13 KB -
I'm using the LabVIEW 8.0 evaluation CD and every time I try using the Instrument I/O Assistant I get this error message "Measurement and Automation Explorer or the Instrument I/O Assistant is not installed correctly. Please install these from the LabVIEW Driver CD." So I tried installing both from the Device Driver CD and still it didn't work. I also tried uninstalling all NI softwares and components and reinstalled everything from the LabVIEW evaluation CD and Device Driver CD and still the same result.
I was wondering maybe the Instrument I/O Assistant will only work after I activate LabVIEW. Is this the reason why I can't use it or does Instrument I/O Assistant also work even if I'm only using the evaluation version? Please help!Glynster -
Yes, Instrument I/O Assistant does work with the evaluation version of LabVIEW 8.0. However, you need to install Instrument I/O Assistant from a version of the National Instruments Device Driver CD that shipped with LabVIEW 8.0 (or later).
NOTE: The link provided for Instrument I/O Assistant 1.0.1 DOES NOT work with LabVIEW 8.0. It is only for LabVIEW 7.x.
You will need to obtain a Driver CD to get Instrument I/O Assistant to work with LabVIEW 8.0
-Tommy -
I am having difficulties getting Labview to work with my NI card. I have a PCI_6225 card running on a Win 7 64-bit install. I had to download all of the drivers and installers from the NI site and during the Labview install, I recieve a prompt asking for my hardware drivers. Since I only have the compressed hardware installer, Labview doesn't like what it sees and continues the installation of LABVIEW. I then attempt to open an analog input channel through the Instrument I/O Assistant which displays the error seen in the image attached.
I know the hardware works because in the Measurement and Automation client, I am able to observe the analog input I hope to collect in LABVIEW.
Is there a fix to get LABVIEW working? I have tried multple installs of LABVIEW and am on a administered computer through my University's IT people. I have 'full admin' rights. Thanks.
Attachments:
error.jpg 254 KBHello jbaxter,
When you download the Drivers from NI's website, make sure you unzip them (extract them) to a folder on your computer before you install them. If you use the NI Downloader it should prompt you to unzip and run the files after the download is complete. You need to either repair, or reinstall DAQmx and NI VISA. Make sure you download the latest versions of these first:
http://search.ni.com/nisearch/app/main/p/bot/no/ap/global/lang/en/pg/1/sn/catnav:du,ssnav:sup/1//en/...
Then go to Control Panel»Programs and Features»National Instruments Software and click Uninstall/Change then go to DAQmx and NI-VISA and click Repair. You can then point to folder that you downloaded from NI's website (make sure this is not a zip folder, but the folder that has been extracted). Or you could choose Remove, and then reinstall them both again. Also if you are using GPIB, reinstall or repair the NI-488.2 driver.
Here are some relevant links:
http://digital.ni.com/public.nsf/allkb/DC808866AF7D5C0986256FCE006E9BAB
http://forums.ni.com/t5/LabVIEW/Again-I-O-Assistant-not-installed-correctly/td-p/1024807
http://forums.ni.com/t5/Instrument-Control-GPIB-Serial/quot-MAX-or-Instrument-I-O-Assistant-not-inst...
http://forums.ni.com/t5/LabVIEW/Install-Instrument-I-O-Assistant/td-p/1471516
Software Developer
National Instruments -
How do I program Instrument I/O Assistant to read a variable in the input string?
How do I program the Instrument I/O Assistant to read a variable in the input string? I can manually type in the string using the Instrument I/O Assistant using the "Write" or "Query" tools but I do not know how to send a variable input to the Instrument I/O Assistant so that variable can be used inside the "Write" string. For example, I have a power supply whose current I want to set to X Amps. I can type the command "PC10" to program the current to 10 Amps, however I want to be able to program it at any arbitrary current. How do I feed the value X into the code for this purpose?
You can't. The assistant was designed to be a quick and dirty way to do some basic communication with an instrument. You can turn it into a VI (right click and select Open Front Panel) and modify it so that your write string is an input to the VI or use it as a template and create your own code with VISA Read and Write primatives.
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How to send multiple commands throught the Instrument I/O Assistant
I am using the Instrument I/O Assistant to set up an instrument driver. I am only using two rs 232 commands. The way I have the Instrument I/O Assistant setup is: first I have a default instrument setup step then I use a write step with the first command, then I read and parse, then I do a write command again with the second command and finally I read and parse again. All of this works fine inside the window but when I run it in my program only the first command's response it outputed . The second command's response is not outputted it just sends a null. Can the Instrument I/O Assistant only handle one read and write, or is my logic wrong?
Thanks for your help
IanHi Ian,
You should be able to perform multiple reads/writes with the Instrument IO Assistant. What termination character are you using? I have seen cases where different termination results in different parsing, which may explain why you're only receiving a null character on your second read. Thanks!
Regards,
Anna M.
National Instruments -
Instrument I/O Assistant Help - Parsing Errors
Hello All -
I am having trouble working with a TSI DustTrak DRX - which does not have its own driver so I had to make one. At this point, all I want to do is send a command to the instrument and get an indicator to repeat what the output is. So far no luck.
1) I think my driver works. The instrument is connected via ethernet. The instrument has a static IP. In MAX when I look under "Network -Devices" it appears there. "Validate" results in a successful connection. If I click on "Open VISA Test Panel/Input/Output" I am able to enter commands (e.g., rdmn\r returns the instrument number) and "Query" and the correct answer comes up. It should be noted that the number of bytes returned for different commands are different, and also that the measurement data is always of variable length, so I often get the "Timeout expired before operation completed" error. For a simple read instrument number command, the number of bytes is predictable, but for the measurement data, it is not, unfortunately.
2) When I put an "Instrument I/O assistant" on the block diagram of a new VI, and add a "Query and Parse" step with the same command (rdmn - no \r this time), I again get the expected value (or when I query the measurement, rmmeas, I get the expected output string). Again, it should be noted I get the "Timeout expired before operation completed. VISA Status code : bfff0015" error. Once I close then reopen the Instrument I/O Assistant configuration window (though not before) I can parse the data, and the token appears as a potential output of the VI. Here I can declare the output as either String or Number.
a) If I declare the output as a string and create a string idicator, an empty string is returned.
b) If I declare the output as a number (it is "8533", so this should be OK), I get the following error (even without creating an indicator before running): "Error 1 occurred at Scan From String (arg 1) in Untitled 5:Instance:0->Untitled 5 Possible reason(s): LabVIEW: An input parameter is invalid. For example if the input is a path, the path might contain a character not allowed by the OS such as ? or @." I know from MAX that the returned value is actuall 8 bytes: \r\n8533\r\n . So, there are no unallowed characters here. And there are no paths involved - no read/write.
Some other info:
1) If I send start or stop commands to the instrument in MAX or the Instrument IO Assistant, I can get the instrument to turn on/off as it should, so I'm clearly comunicating to the instrument correctly.
2) I get the same behavior if I parse the returned measurement string - \r\n385,0.013,0.014,0.015,0.020,0.035,\r\n from MAX - as a set of numbers (that is, with "Error 1 occurred at Scan From String (arg 1) in Untitled 5:Instance:0->Untitled 5 Possible reason(s): LabVIEW: An input parameter is invalid. For example if the input is a path, the path might contain a character not allowed by the OS such as ? or @.")
Any help would be appreciated!
Thanks.Hi James - Thank you very much. I actually found the problem and was able to fix by changing how the output text was parsed - the \r\n in front and back was confusing it - and making sure that I flushed the read buffer after reading, just in case. I also had to modify so that the first character was read and discarded before reading (and using) the rest of the output string.
Now for a rookie question: I've got it set up as a working VI now - how do I declare which variables are inputs and outputs when I put it in another vi?
Thanks. -
Instrument I/O Assistant problems
Hi,
I am having trouble using the I/O assistant through my parallel port. It is not writing to it. The VI example, Parallel Port Read and Write Loop, works just fine. Is there a way to use the I/O Assistant instead?
Thanks,
RyanHi Ryan,
What sort of problems are you having? You should be able to use the Instrument I/O Assistant to communicate through the parallel port. This tutorial, Instrument Control in LabVIEW Tutorial, shows how to set up the I/O Assitant. If that's not working properly, what errors are you seeing? Have you run NI-Spy to see where those errors are occuring? Are you sure that you are sending the correct termination?
Let me know if you need any other help,
Meghan
Applications Engineer
Message Edited by Meghan R on 07-10-2007 02:26 PM
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