Task settings for a wls 9215

[djacobs]

I recenly puchaed a WLS-9215 for a real time telemetry application. While the sample rate was low ~2000 hz and using only 1 channel. I am going about 3-4 minute before I get a time out error message. I am at about a 30m range in shop enviroment (lots of metal pipes on racks) I was curious if there was any sampling rate/channel combinations that would help me increase my range and relibility. If I reduce my sampling rate will this have any effect on my system relibilty/range. Is ther any setting on the WLS for redundency, buffering, error corection etc.

Thanks

Dean 

[John_P1]

Hi Dean,

Welcome to the NI forums!  Unfortunately the issue you seem to be having is with the connectivity of the wireless DAQ to your computer.  Changing the sample rate would not likely make a difference, since once you lose connection the task will timeout regardless of the rate. 

Could you tell me more about the environment you are in and your network configuration?  For example, do you have a direct Line-of-Sight between your wireless DAQ and your computer/router?  Are you going through a router?  Any additional information would be helpful, the problem is likely a networking issue and we may be able to offer some suggestions to improve performance.  Thanks for posting, I look forward to hearing back so we can continue to look into the matter.

-John 

[djacobs]

Currently I have the equipment set up in my office now (1m range). I had limited success putting the unit in our shop. Even in my office I get time out errors on a regularly. Some times I can connect ,but other times it will not even connect to at all or short periods of time. I am using an AD-hoc network. Currently I have disabled the internal wireless card on my laptop. I am using an external USB wifi adapter (Linksys WUSB54G). I have set it use an alternate manual configuration with a IP (10.0.0.1)sub net 255.255.255.0, The wls-9215 is set for an IP of (10.0.0.2 ) sub net 255.255.255.0 on channel 2 with adhoc selected. Currently I am leaving the connection open. I currently have "excellent signal strength". From our shop I get 2/5 bars of signal. I selected channel 2 because the WLS documentation indicated it had the highest transmit power. I have disabled Windows Firewall, to prevent any complications. I can see another wifi network, either someone in this office or in a bay adjacent to our building has some form of wifi enabled. I am not sure if this is a interference issue. I assumes wifi equipment will channel hop in event of interference. The unit itself always has it's led indicating a wireless connection iluminated. When my computer indicates I am connected to the "TEST" peer to peer network. I have tried to ping 10.0.0.2 and it usually times out. Some ping events have resulted in round trip time of up 3000ms. Would there be any benefit to purchasing a router/ access point (not sure about the difference between the two). This application will always be a direct link.  The final application will be a high speed( 2 channels 2000Hz) telemetry application,Pressure measurements will be taken during the stimulation of and oil/gas well. The environment will be outdoors subject to wind snow and rain not to mention lots of heavy equipment operating in the area. We will be able to park the operator pickup (location of the laptop) more or less in line of sight of the enclosure with the wls-9215. I will be using external antennas on both ends to increase the range/reliability, if I need too. I need to maintain this link for 3-24 hours. I don't know I might even need an wifi amp of some sort to get the range I need ~50-100m.

Thanks

Dean

[John_P1]

Hi Dean,

It sounds like you have a fairly noisy environment, so I would recommend that you first try all 11 channels available to see which has the least interference present.  When working with wireless DAQ devices at my office, there are certain channels I need to avoid due to interference from our test equipment.  I would adjust the channel you are using, then try pinging the device to see if there are any channels that give better performance than channel 2.

It would also be beneficial to use DHCP with a router as opposed to Ad-Hoc network settings.  You could try setting up your router in-between the computer and your WLS-9215 to minimize the propagation distance and the effects of noise.  You may want to use a wired connection between the router and your computer if possible.

External antennas should also prove helpful--a directional antenna can do wonders for improving your SNR in a noisy environment.

Let me know how everything goes, if you are still experiencing any problems don't hesitate to post so we can continue to investigate.

-John