Error 50405: Connection timed out with a WLS/ENET-9163

Hardware: PXI/CompactPCI>>Controllers

Problem:
When I run test panels or perform a NI-DAQmx Read on a Wireless DAQ device I get Error 50405 occurred at test panel no transfer in progress because the transfer was aborted by the client. What does this mean?

Solution:
Error -50405 essentially means the network connection timed out. This indicates a poor or intermittent network connection. If you were to ping the WLS device in this state, it may take many milliseconds to reply, or it may not reply at all. There are two ways to mitigate this error.

Improve the Network
- Replace wireless connections with wired connections.
  If the host computer and the WLS device are both connecting to the Wireless Access Point (WAP) wirelessly, then the WAP repeats the wireless traffic from the WLS to the host and back again. This doubles the wireless traffic. If possible, wire the host computer to the WAP, and connect the WLS to the WAP wirelessly.
- Ensure clear line-of-site between the WLS and the WAP.
  Any physical obstruction between the WLS and the WAP attenuates the wireless signal. If removing the obstructions is not an option, reposition the WLS, WAP, or both, to obtain better line-of-site.
- Properly position the antennas of the WLS and WAP.
  A simple stick antenna (like the one that ships with the WLS-9163) radiates the wireless signal most effectively perpendicular to the antenna. Positioning the WLS antenna on the same horizontal plane and the antenna of the WAP, and orienting the antennas straight up-and-down (so the antenna is not broadcasting into the ceiling or floor), will help improve the wireless link.
- Select a different antenna configuration.
  Choose a WAP with a boosted signal or directional antenna. If the WAP has two antennas (such as the NI WAP-3701), positioning each in opposite directions may improve the signal.
Increase the Timeout
- Two registry keys on the host computer adjust the length of time before the timeout error appears. By allowing more time, the system will be more tolerant of poor network connections.
- Open the Windows registry and navigate to HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\niemrk\Parameters\ Note: If Parameters does not exist, right-click niemrk»New»Key. Rename the new key Parameters.
- If the Parameters key already contains DWORDs for ConnectionTimeout and DiscoveryTimeout, skip this step. Right-click Parameters»New»DWORD Value. Name the new REG_DWORD ConnectionTimeout. Repeat this step, adding a new DWORD Value for DiscoveryTimeout.
- After both DWORDs have been created, double-click each, select the Decimal radio button, enter a number into the Data Value field, and click OK. The number you enter is the number of milliseconds before the timeout error will appear. The default is 2500 ms. A good rule-of-thumb calculation is provided here:
  
  Timeout = 12MB / (Number of Channels * Scan Rate * Number of Bytes Per Scan)
  
  Consider the example of a 4-channel analog input task at 25KS/s with a 16-bit module:
  
  12MB / (4 * 25KS/s * 2B) = 60 Seconds
- It is recommended that you increase the DAQmx input buffer size to accommodate the increased timeout length. Before the DAQmx task is started, place a DAQmx Configure Input Buffer VI. The value wired into the buffer size (in samples per channel) can be determined from the length of the timeout you configured.
  
  Buffer Size = Sample Rate x Number of Seconds Before Timeout

Report Date: 11/05/2008
Last Updated: 02/12/2009
Document ID: 4R49MMD2

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