WebScan is a browser-based CloudTurbine data viewer.  It connects to the CTweb HTTP/HTTPS server to stream selected data sources. View real-time or playback data from one or more numeric, image or text channels. The Demos play recorded data using WebScan; browse them to get a feel for the WebScan interface.

WebScan is available from the WebScan repository on GitHub.

The image below points out some of the WebScan controls and features.

Click the small gear icon in the upper right corner of the screen to pop up the Options Menu.  This menu is shown below along with a description of the menu items.

WebScan Options Menu
Option Description
Smooth Make smooth plot lines.  Not applicable to image or text channels.
Fill Color the area under a plot.  Not applicable to image or text channels.
View Duration of data to display in the plot. Not applicable to image or text channels.
Plots Total number of plots to include in the WebScan screen.
Columns Organize plots into this number of columns.  Chose from auto, 1, 2, 3, 4.
Refresh Sets the baseline rate at which both real-time and playback (scrolling) data will be updated.  Chose from Fast, Normal, Slow.  The update rate is adjusted using heuristics and is not a fixed value, but will be relatively faster or slower depending on the Refresh setting.  The “Normal” setting should be good for most cases.
Scaling Display scaling for numeric data.  Not applicable to image or text channels.  Chose one of the following options:


  • “Auto”: plot includes some blank vertical space above and below the displayed data
  • “Tight”: the highest numeric data value touches the top of the plot and the smallest numeric value touches the bottom of the plot
  • “Manual”: mouse-drag data up or down on the plot, zoom plot-scale with mouse wheel.
Save to URL Create a URL which specifies the current data channels and plot options and put it in the browser’s address bar.
Help Pop up WebScan help documentation in a new browser tab.


Setup your own CloudTurbine data service

Follow these steps to setup your own CloudTurbine data viewing service using WebScan and the CTweb HTTP/HTTPS server.

We typically setup the program and data files as shown in the figure below. The top-level CloudTurbine folder contains the following:

  • CTdata directory, contains CloudTurbine source data; the example below shows one source, SimpleSource, located in CTdata (this is the sample source discussed in Writing CT source apps).
  • CTweb directory, contains the WebScan files, available from the WebScan repository on GitHub.
  • CTweb.jar, executable for the HTTP/HTTPS server. This application is included in the CloudTurbine release distribution.


With this directory structure in place, start the CTweb server and point a browser at the server’s address.  This is done as follows:

Start CTweb server: for the folder structure shown above, cd to the CloudTurbine directory and run

Bring up the WebScan interface: Running on the same computer the CTweb server is running on, bring up the WebScan interface in a browser by going to http://localhost:8000 (where “8000” is the default CTweb server port).  View data remotely by using the appropriate IP address or host name in place of “localhost” in this URL.

While it is convenient to “co-locate” CTdata, CTweb and CTweb.jar as shown above, they don’t need to be. You can specify the locations of the CTweb and CTdata folders using options on the CTweb.jar command line.