cdaq 9191 timeout

[trenwand]

I currently have 2 separate cdaq 9191 chassis connected to an ad hoc network created from a windows 7 computer. There is an issue with connectivity on one of the chassis timing out after a few successful readings, even though there are two bars of signal on the wireless network.

To remedy this issue I connected the chassis directly to the computer that is doing the data collection through an Ethernet cable, and it seems to work fine

In the future, there will be 3 cdaq 9191 chassis on the system, and since it appears that wireless will not work in our environment due to noise, would connecting all 3 chassis to the computer through a 4 port Ethernet hub give any issues when reading the data?

Any suggestions would be greatly appreciated.

[Brian_A]

Hi trenwand,

There shouldn't be any issues with 3 cDAQ-9191 chassis connected via ethernet to a hub. We test much larger systems than this to ensure the device work properly in large system deployments. 

It sounds like you are already plannning to work around timeout issue by going with a wired connection, however a quick troubleshooting step would be to check for a channel not being used by other wifi devices using a wifi analyzer like the ones suggested in this KB. If there is a clearer channel you may want to try that one and see if you still experience the timeout issue. 

Cheers,

Brian A

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

National Instruments 

[abh]

Hi Brian_A,

I would like to know that how would i be able to connect two NI cdaq 9191 attached with NI 9234 module over wi-fi of the laptop.

Is this is possible to connect two cdaq 9191 over a wi-fi Network on the same workstation and also are we be able to get the data simultaneously from both the cdaq 9191.

Reply ASAP.

Thanks

[Brian_A]

Hi abh,

I believe you are referring to creating an ad hoc network from your laptop and having two cDAQ-9191's then connect to the ad-hoc network. While this is technically possible I would strongly advise against it due to instability issues with ad hoc networks which will be compounded due to 3 devices on the network. 

Preferred solution: Use a usb powered access point to create a wireless infrastructure and connect the computer to the cDAQ-9191s through its network. 

Examples: Edimax N150, Asus WL-330NUL, TP-Link TL-WR702N

Alternate solution: Use a usb wireless adapter that supports software Access Point mode. I would use caution if going with this option because the performance is dependent on the software implementation by the manufacturer and we do not test our devices with software created Access Points. This would still be a better option than an ad-hoc network.

Examples: Asus USB-N66, TP-Link TL-WN321G, Edimax EW-7612UAn V2

As a general wireless DAQ best practice, ensure that your VI has proper error handling. Even under ideal conditions, wireless networks can momentarily be interrupted so your VI should be programmed to detect these errors and reestablish connection if it is lost.

Cheers,

Brian A

R & D Staff Mechanical Engineer | PXI Platform 

National Instruments 

[abh]

Hello sir,

As recommended by you i am using the USB powered wireless adapter of cisco and connected one of my c-daq 9191 to it , but i am unable to connect the second c-daq 9191 to the network. How do i proceed? please help . Is there any link of document to be referred for connecting the two c-daq 9191 devices to the USB powered adapter.

Thanks and Regards,

Abhinav

[WenR]

Hi abh

According to what I see, you should be able to connect the second cDAQ to the Access Point just the same way you did with the first one, after configuring the proper address and sub network, the device should be available in the same way as it works with wired connections on an Ethernet network.

I was not able to find a guide describing exactly the steps for this process, could you describe a little further which steps of the configuration of the second cDAQ is giving you the issues?

Thanks

Wen R

[Brian_A]

Hi Abhinav,

Can you give the exact model number for the cisco wireless adapter? Not all wirless adapters support software access point mode and the ones that do use thier own propriotary software. You will have to go to the manufacturers website and download their software to set up the usb wireless adapter in software access point mode. They should also have information on setting up a software access point. 

Once the software access point is set up you should be able to connect the cDAQ-9191s by selecting Connect to wireless network for the Wireless Mode and searching for the software access point created by the usb adapter. 

Again I want to caution that NI does not test the cDAQ-9191 with usb adapters running in software Access Point mode since the software is propriotary and there is not a industry standard for wireless adapters running in software access point mode. 

Cheers,

Brian A

R & D Staff Mechanical Engineer | PXI Platform 

National Instruments 

[abh]

Hi, Brian sir

Actually the issue was resolved last night itself. the wireless adapter i am using is having software access point feature in it. Actually the very silly mistake i did is in my MAX where i configure my device , in network setting i choose the option "create wireless network" instead of "connect to wireless network" thats why the device is not connecting.  Finally the issue was resolved and i am able to get the data from both the c-daq 9191's simultaneously connected to CISCO USB wireless adapter.

Also using wireless adapter it won't take much time to connect  where as using laptops wi-fi and making adhoc network the connectivity is instable.

Thankyou.

---

[Brian_A]

I am glad you got your system working! 

Cheers,

Brian A

R & D Staff Mechanical Engineer | PXI Platform 

National Instruments