DSC and DAQmx / DAQOPC client not compatible with DAQMX

[Clark@Houston]

It seems that the DAQOPC server that interfaces with LabView's Data Supervisory Control module is not compatible with DAQmx devices set up on MAX.  It is compatable with "traditional" virtual channels, but I have not gotten it to recognize any channels through either the Tag Configuration, the DSC configuration wizards or the Sever Explorer wizards.  I have done everything I can to clean the registry, reload DSC and OPC server files, and everything I can find on NI's website to address any issues with a breakdown in communication, including issues with Windows XP, and activating DAQOPC server registry.

My DAQmx channels are actually refering to simulated devices, and I was able to get DSC to recogize them as memory tags, but I have yet to get LabView to get the memory tags to pull the data from MAX.  I set my acusition rate to be 10 times faster than the Niquist frequency of the "simulated" analog signal for the DAQmx simulated devices.  I also know that LabView can see the simulated devices when not using DSC because I was able to generate code where the data was visible (again DSC memory tags not used). 

In summary, when DSC tries to reference tags that point ot DAQmx channels, it can't see the data.  Neither can any other DSC utility like NI Hypertrend, or Historical Data Viewer in MAX see my DAQmx channels.  When I say it can't see, it is not seeing data change or the presence of data.

I am going to need to make my own VI-based-server just to use DAQmx?

[.avi file]

Greetings!
      Hello and thanks for the inquiry. Unfortunately at this time we cannot log data when trying to use DSC to reference DAQmx channels. We are aware of the issue and working on that. You could learn more about DAQmx I/O servers for connectivity to all data acquisition devices in the following link. This mentions the benefits of LabVIEW 8.0.

     http://zone.ni.com/devzone/conceptd.nsf/webmain/ad8bcd33134eb6ce8625708c004a8a9e

Thanks and hope this helps
Good luck
Best regards
Avi Harjani

 

[.avi file]

Greetings!

     To summarize as pointed to the link in the earlier email, you will have to use LabVIEW 8.0 and DAQmx 8.0 which are already released. You could use the shared variable engine in 8.0 and not worry about using any OPC server as it is all now the shared variable engine.

With the LabVIEW 8 shared variable engine, you can share data with any node in the system including real-time nodes, historical databases, and Web-based supervisory consoles. NI-DAQmx 8 enumerates all NI-DAQmx global virtual channels configured in the Measurement & Automation Explorer (MAX) utility, including analog input and output, digital input and output, and counter input and output virtual channels, making them available in LabVIEW and to other system nodes through the shared variable engine.

http://zone.ni.com/devzone/conceptd.nsf/webmain/1cd63ee451034be88625708f0058e209

You could start building your application with LabVIEW 8.0 and DAQmx 8.0 found in the following links. And later when DSCS 8.0  releases you could enable all the DSC (Data logging) features and you will be good to go. Hope this helps.

http://digital.ni.com/softlib.nsf/webcategories/85256410006C055586256BBB002C128D?opendocument&node=132060_US

http://digital.ni.com/softlib.nsf/websearch/5697CF4D244EF858862570990075089A?opendocument&node=132060_US

Thanks much and have a great day
Good luck
Avi Harjani

[mbhatti2000]

Dear AVI Harja....,
I am using a real time system PCI-6259 M-series which is connected to the ethernet in the lab.
I have a similar question related to this thread, I want to use shared variables to send and recieve signals over the ehternet. I have made a  DAQmx  VI and I need to specify a channel to send the signal , as the real time system is not connected to my computer so I cannot choose any physical channels,  how  can I choose  a  channel ( a  global  virtual  channel ) in the DAQmx Program?

Is it possible or not and if not is there any other way to do this?

My second question is I am using NI-DAQmx 8.0 , will installing  "NI-DAQmx Base Version 2.0 for RTX" which also supports M-series boards, will  be helpful for me?
 
Thank u,
Sincerely ,
Munir Afzal Bhatti.

[Laura F.]

Hello Munir,

You should be able to choose the physical channels in the DAQmx program.  Make sure that you can see your PXI system under the Remote Systems section of Measurement and Automation Explorer.  Are you targeted to the controller when you look for the physical channels in your VI? 

Also, if you are using LabVIEW 8.0, you could create a DAQmx Global Channel in your RT project to take advantage of the Shared Variable. 

You do not need NI-DAQmx Base 2.0 for RTX because this is specifically for doing data acquisition on computers running RTX, but you have a RT controller that works with DAQmx. 

I am not sure if I have really understood the problem that you are facing.  Please post back with more information if this is the case.

Thanks,

Laura

[mbhatti2000]

Dear Laura,

Thank you for clearing the confusion about NI DAQmx Base 2.0 for RTX. I am a new user in Labview I shoud add this first.
Actually I am using LabView 8 and  have used shared variables to send signals to a specific channel in the PXI system which is in the lab. I can see the PXI system in the MAX, and I have also attached some screen shots.I have  also made a  Global  Virtual  Channel  in the PXI remote system.

I did not understand this question: "Are you targeted to the controller when you look for the physical channels in your VI? " could u make explain how to target the controller when I look for Physical Chanels?

I am also attaching the screen shot of the program that I am using. When I click on the counter1s or 2s and choose browse I cannot see the global virtual channel that I have created on the remote PXI system.
How can I make the channels in the PXI system available in the I/O channels?

thanx
 

[Laura F.]

Hello Munir,

The screenshots you posted really helped me understand what the problem is - thanks!

In the program you are using the box that allows you to browse for channels only allows you to browse for physical channels (Dev1/ctr0) which are different than global channels that you create in MAX.  The block diagram of your program takes the physical channel you are using as an input to the DAQmx Create Channel VI and creates a task that uses this channel. 

The way it is set up, you can specify the physical channels on your remote system.  The picture you attached shows me that you are currently referencing the PCI-6259 you simulated in MAX.  If you want to use the actual PXI-6259 in  your system, you would reference it using "PXI1Slot2/ctr0".  

However, if you prefer to use the global channel you created in MAX, delete the DAQmx Create Channel VI and wire a DAQmx Global Channel constant from the DAQmx Constants & Property Nodes palette to the task/channels in terminal.  Since you have already created the channel in MAX, you do not need to do it a second time with that VI. 

You can ignore the question that is confusing you.  It has to do with using LabVIEW 7.1 rather than 8.0.

Please let me know if you have questions about all of this. 

Laura

[mbhatti2000]

Dear Laura, Thanks for the reply, I found the DAQmx Global channel constant  and sending a screen shot of it. I try to find the global channels that I created in the MAX remote system, but they do not show. I try to create new one but it says that no physical device found.
how can I get these global virtual channels?
thank u in advance.

[Laura F.]

Hello Munir,

In order to browse to the Global Channel you created for your remote system, you must be targeted to the RT controller.  In LabVIEW 8, the way to do this is by using the new LabVIEW Project Window.  You first add a new target by right-clicking on My Computer and choosing New >> Targets and Devices.  You need to know the IP address of your RT controller to do this.  There is a great flash animation about how to do all of this named LabVIEW Project Demonstration at www.ni.com/realtime/software under featured resources.  Watching this will be much easier than me trying to type out all of the instructions.     

After you have added your RT controller to the project window, you add a VI to that target that you want to run.  As long as the VI with the global channel constant is added to the correct target, you will be able to browse to the channels that you have created.

Please try this and let us know how it goes.

Thanks,

Laura

[Laura F.]

Hi Munir,

On an additional note, you may need to check the VISA security options to be sure that your host computer has permission to access the RT controller.  To do this, go to Remote Systems in MAX and expand the software folder for your RT system.  Click on NI-VISA and then choose the VISA Options tab.  Choose security and make sure that the IP address of the computer you are using is in the Remote Access List, or an asterisk (*) is in this list to give permission to all IP addresses. 

Laura