NI 9191 - wireless system - problem in acquisition

[luis_ferreira]

Hello,

I have conducted the configuration of a system that has two NI 9191 devices, wireless version, according to:

http://digital.ni.com/public.nsf/allkb/BC8A12AD883D6825862579E500766E15

I have both devices in "running" and properly configured:

But sending data is always failing.

My program requires two data inputs of equipment C2 and four data inputs of equipment P2 (six data inputs in total):

This error occurs, and the program is stopped.

Someone can help me to get the two devices to acquire data without errors or failures?

Thank you for help!

luis_ferreira

[Brian_A]

Hi luis_ferreira,

The error most likely indicates a network timeout. Can you describe the network topology of the systems Including IP address and Subnet masks for all addapters. Also ping each of the cDAQ-9191 and post the results. You can also try the things outlined in this KB. Do you have the option to use a wireless access point for the network instead of Ad Hoc connections? 

Brian A

R & D Product Support Engineer | WSN/Network DAQ/Academic

National Instruments

[luis_ferreira]

Hello Brian,

I did the configuration of an ad hoc network.
On refresh, it was determined the IP of each device.
On my PC, the IP is automatic.
I'm not using subnet masks. Is it necessary?

I'll try to check the KB!

I use the equipment supplied in places without access point.
That's why this setting is important to me.

Thank you for your help. I'll try to use the KB, and then say how it went.

Luís Ferreira

[luis_ferreira]

Brian,

I tried the suggestions, but my system does not work properly.
Is there a tutorial for this system? Using ad hoc networks?

The PC needs a static IP? I'm on automatic.

Normally this happens:
The device 1 works. The two usually does not work.
Sometimes the equipment 2 works, but then stops sending data.
Sending data (both devices) does not occur simultaneously. I want to see the data in near real time, but that now seems almost impossible.

Actually I have two questions then:
1st. Two devices work properly in ad hoc network.
2nd. Receiving the data simultaneously.

I hope you can help me.

Luís Ferreira

[Brian_A]

Since you do not have a router or access point I would try setting up the Ad hoc network from the PC (Steps for Win7). Then have both of the 9191's join that network. Then turn off the wired ethernet controller on your pc from the control panel. If you still have issues try editing the registry keys outlined in the previous KB I linked. You can also try updating the firmware of the 9191 to the latest revision (1.4) if they are not already at that revision. If that still does not work I would suggest getting an access point and use that to set up the network infrastructure. 

You may also want to contact your local NI support as they can provide quicker responses if this is time critical. 

Brian A

[luis_ferreira]

I got to get data from the two devices!
Finally!

I changed:
I created an ad hoc network on my pc, not the device as it had before.
Is this enough for a change so great?

I now have a new challenge ahead:
Synchronize the two devices!
Is there anything I can do in technical terms?

Thanks for your tips.

Luís Ferreira

[luis_ferreira]

I'll try to explain better what is happening:
one of the equipment: the data arrives in near real time. (OK :))
other equipment: there is a lag data. information arrives a few seconds later. (: ()

Is there a way to get information to both near real time?

Luis Ferreira

[Brian_A]

You can try change acquisition settings but wireless and ethernet communication are non deterministic so there is no way to guarantee you are going to get the data back in a certain amount of time. Reducing the buffer size will send back data in shorter intervals but ethernet/wireless communication tends to do better with larger chunks of data. You can post a screen shot of the data acquisitions part of your code and see if the community can give you feedback on how it can be improved. Also if you haven't changed the topology to have the 

[luis_ferreira]

Hello!

They are the parameters that I'm using.
Do not quite understand, what data you asked.

[Pedro_Mendes]

Hello,

I'm having a similar problem.

When I connect two 9191 chassis, one is fast and one is slow.

I've tried:

- Ad hoc Network
- Access Point

But I have evidence:

My software has 3 levels:
1 - DAQ
2 - MENU
3 - Various Sub-vi's MENU

That is, I run the menu, the menu calls the sub sub vi and vi corresponding calls to the DAQ.

My evidence is that when the DAQ is in Sub Vi, response data from 2 chassis is fast.

It is a matter of software programming? Sync? How can I solve?
 
regards,
 
Pedro Mendes