Problem

E-WMS on my scanner logs out after a specific time (15 minutes), or connection is lost after a specific time duration

Cause and solution

There are some time-out settings involved when using IIS and E-WMS ASP. 

1. General session timeout
   For security reasons (since you login with a password) E-WMS is configured to log out a session after 15 minutes of inactivity. You can change this period by editing the file WEB.CONFIG on the IIS server, in the WMS ASP root folder. Search for the text 'timeout' and change the factor as needed:
   
      
   
   Please note that on E-WMS updates, the file Web.Config will be overwritten with the default file again, so this needs to be changed again after each update.
   
   
   
2. There is a connection HTTP timeout per type of WMS client. The file for this setting depends on the client used:
   • When using WMSclient: WMSclient.config
   • When using ERF: ERF.config
   • When using (Pocket) Internet Explorer: Web.config

   
   
   
   httpTimeout
   This is the time in milliseconds (so default 30 seconds) the client waits for a server response when retrieving a web page.
   
   keepAliveInterval
   This is the interval in seconds (after inactivity) after which the client retrieves a dummy web page from the web server, to make the IIS server and the hand terminal's WLAN adapter believe that there is still activity.
   
   Please note than on updating E-WMS, this file will be overwritten with the default file, so any changes need to be applied again after the update.
   
   

3. When you have configured an IIS application pool, the 'advanced settings' screen of the application pool configuration contains an 'Idle time-out' parameter:

   
   
   

4. Besides these IIS settings, the hand terminal will have power saving settings enabled by default. Please consult the documentation of the device. In general, you will have a screen setting to 'dim' the screen already after a few seconds of inactivity, and in the 'power' options you will see several settings to limit battery usage. In specific power saving options, also the internal wireless network card will shut down, thus resulting in loss of connection to the wireless network.
    
   To avoid that the wireless card of the hand terminal is deactivated when the device enters power saving mode, you can configure the option 'CAM' (Constant Awake Mode) in the wireless settings of the device. Where this option is located, depends on the specific device. For instance in the Summit Client Utility, this can be found in the 'radio' setting 'Power Save'.
   
   Enabling CAM mode will drain the battery much faster, but provides the best wireless network performance.

Related documents

• E-WMS - history and samples of hand terminal client software
• How to determine the WMS ASP IIS folder
    
  
• E-WMS start page