Instrument I/O Assistant RS232 communication problem

Hello!
I am currently trying to create an instrument driver for a Ballard "Nexa" fuel cell with the Instrument I/O Assistant.
The fuel cell data is 43 byte sent every 200 ms at 9600 Baud (8N1). I do have a working communication, because I can see the data coming in when I´m using an ordinary terminal program. The Instrument I/O Assistant however does not seem to receiver anything.
Here´s what I do / what I see:
Create an empty VI
Place an "Instrument I/O Assistant" block on the block diagram, the Instrument I/O Assistant windows pops open.
Choose device: COM1 or COM2, depending on where the Nexa is connected (Choosing different devices has no influence on my problem)
Add step "read and analyze"
Click "Run this step" to read the data coming in from the serial port, but nothing happens until the the timeout set on the choose device tab has expired, then I get a timeout message (see attached picture).
I added a RS232 diagnostics plug that has blinking LEDs while data is flowing to make sure there is data coming in while the assistant is running.
I a previous thread, I read that the Instrument I/O Assistant has a bug concerning the locale settings of windows:
http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HOID=5065000000080000002DBF0000&UCATEGORY_0=_49_%24_6_&UCATEGORY_S=0&USEARCHCONTEXT_TIER_0=0&USEARCHCONTEXT_TIER_S=0&USEARCHCONTEXT_QUESTION_0=Instrument+I%2FO+Assistant+is+not+communicating&USEARCHCONTEXT_QUESTION_S=0
So I tried the same after switching my locale settings from german to english, but with no success, the I/O Assistant still seems to see not input.
Does somebody have another s
uggestion? Has anybody written a serial read/parse VI from scratch that he/she might share so I can use that as a starting point, if the assistant keeps failing for me?
Thank you,
Ingo.
Attachments:
errormsg.gif ‏5 KB

Hi TN,
As I just started using LabVIEW, developing an instrument driver seems like some pretty heavy stuff. For now, I´ve managed to have someone else write the communications backend, I´ll only do the data conversion and display. But I´ll for sure take a closer look at that communications VI so I ´ll get it done myself next time...
Anyway, thank you for your reply, I appreciated it.
Ingo.

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GPIB and RS232 communication problems

I've been having several "interesting" problems with GPIB and RS232 communications in LabVIEW VIs. Some I'll mention at the end for curiosity, but right now I'm facing a rather big problem. I'm essentially self-taught at doing LabVIEW (using 8.5.1 right now), but by now I've had a lot of experience as their either has not been any drivers or pre-made VIs for the instruments I've needed or I've not been able to get the available drivers to work and had to write my own anyway (such as with the HP 3458A), but nothing seems to be working right now. I'm not at work, but we typically find forum sites blocked anyway (I can't even download the NI drivers at work since they house them on a ftp server, go figures) so I can't give the VI itself (it wouldn't be easy to get approval even if I could) so the best I can do right now is in words describe everything I've tried. I will be happy to post follow-ups of specific details if I can if they would be helpful.
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Thanks.
-Leif
Leif King
Metrology Engineer
Oak Ridge Metrology Center

Greetings Leif,
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As for your other issues, please post seperate threads for each so we can help you accordingly. Thanks!
Sincerely,
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Aldo A
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Message Edited by Meghan R on 07-10-2007 02:26 PM

Problema con el instrument I/O assistant

Disculpen espero me puedan ayudar, he querido utilizar el Instrument I/O Assistant, pero siempre que lo pongo en el diagrama de bloques me sale una ventana diciendo:
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Ya intente reinstalar los drivers del I/O desde el disco de evaluacion que tengo, tambien baje unos de la pagina, tambien baje el ultimo DAQmx, e instale de nuevo el MAX, pero nada lo resuelve.
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Estoy utilizando LabVIEW 8.5, y windows XP

Hola Rounel,
es posible que al desinstalar e instalar el MAX se hayan dañado algunas secciones del mismo. Te recomiendo desinstalar todo el programa de National Instruments incluyendo LabView y Drivers e instalarlos nuevamente, primeramente LabView y posteriormente los Drivers, usando el CD de Drivers. Si no tienes este CD de Drivers, puedes bajarlo desde nuestra web de NI, en la siguiente liga:
http://joule.ni.com/nidu/cds/fn/p/sb/navsRel/lang/es?q=drivers&x=14&y=13
Este es la versión que deberás bajar.
NI Device Drivers
2008.03
Windows
Controlador de Hardware
Marzo 2008
Inglés, Chino (Simplificado), Francés, Alemán, Japonés, Coreano
Una vez instalado todo nuevamente, abre el programa de MAX y verifica en la sección de Software (sobre el árbol de secciones) que estén instalados los drivers de NI-VISA y NI-488.2 ya que estos son requeridos por el Instrument I/O Assistant.
De lo contrario tendrás que bajarlos de las siguientes ligas e instalarlos:
NI-VISA
NI-488.2 (necessary only if you are using GPIB)
Si fue necesario instalar estos drivers (como segunda opción) entonces tendrás que desinstalar e instalar nuevamente el Instrument I/O Assistant. Para instalar el Instrument I/O Assistant usa el NI Device Drivers que bajaste de la página de National Instruments. No es necesario que instales o desinstales el DaQmx y el MAX.
Espero te sea de ayuda esta información y no dudes en comunicarte conmigo si tienes alguna duda.

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In the function pallette both input and output subpallettes have instrument assistant express vi.But, when I put in the block diagram window Instr I/O assistant configuration dialog box doesnot appear.I double clicked instr assistant icon but it did not work. Labview version is 7.1.Does anyone has clue to overcome this problem?
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Hello phylab,
The Instrument I/O Assistant (IIOA) is used for easily communicating with GPIB instruments in Labview. For Labview version 7.1, the IIOA is available on the shipping reference driver CD. It should be automatically
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I want to communicate a RS485/2-wire device through COM1. I tried Instrument I/O Assistance to write to COM1(hex string with or without end bye:0D0A), something happened on the bus, but is not defirrential signal, and device didn't recognised them.

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.
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How do I program Instrument I/O Assistant to read a variable in the input string?

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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.
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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.
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The 6363 is programmed with DAQmx functions. You would use the DAQ Assistant.

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.
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INSTRUMENT I/O ASSISTANT EXPRESS VI - PERFECT PARSING NO OUTPUT

I am using the Instrument I/O assistant express VI to parse data from a (visa) serial port. Neatest thing since sliced bread! I initially send a write command followed by eight read/parse commands to retrieve eight tokens each ending with cr/lf. All seems well during i/o setup. The Vi compiles and shows all eight string tokens. I then connect each one to a string indicator. When the Vi is run no data appears in the indicators. Repeated runs during the I/O setup shows tokens extracted perfectly. What's going on?

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Instrument I/O Assistant blank

I have been having problems getting a code to work. So, I purchased LabVIEW for Everyone (a book) to see if I could figure out how to get the code to run right. (here is a link to that thread )
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Thanks Dennis.
I believe the book recomends it to avoid having to use the write functions and PMTK code. It basically says to use it to make life simpler. This is a beginners book and it really doesn't get into Visa functions very much. I was hoping it would dive a little futher into them.
I still don't know why you had me close one string and then open another config file only have insert another write function. I know I'm lost, but I was hoping this might shed some light on the whole situation...

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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 ?
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Regards,
Isabelle
Ingénieur d'applications
National Instruments France

Instrument I/O Assistant RS232 communication problem

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