December 30, 2010

LXI Instrument - Accessing The Remote Web Interface

First of all, LXI refers to LAN eXtensions for Instrumentation. It is an Ethernet-based standard architecture for instrumentation and test system communications protocol. Having the power of Ethernet and Web within, test systems can now be designed to be local, remote, distributed or time-aware. Since it is running on LAN, the physical cost of connection is significantly lower than that of GPIB. However, the other comparisons between LXI and GPIB will not be covered in this article.

There are three LXI classes defined, with each higher class inheriting the properties of the lower classes:

  • LXI Class C: The base class of LXI. These devices must have a standard Ethernet interface, serve a Web interface viewable from a standard web browser and provide IVI drivers.
  • LXI Class B: Expanded triggering capabilities such as peer-to-peer communications, multicast messaging and precision time protocol (IEEE 1588).
  • LXI Class A: Highest class of LXI. Adds hard-wired trigger bus for precision triggering between devices in close proximity.
Click here for a list of products that are registered with the LXI Consortium along with their LXI Classes.

As highlighted in yellow above, LXI instruments must have a built-in Web interface as it is a base requirement. These instruments can be observed or controlled through Ethernet using a web-based user interface, allowing user to remotely access the instrument even thousands of miles away.

We shall take a look at a real example of how to link the PC to an LXI instrument, in this case, an Agilent 34410A 6.5 Digit High-Performance Multimeter which is an LXI Class C. It is just one of the many ways to connect the PC to the instrument via LAN.

Figure 1: Agilent 34410A 6.5 Digit Multimeter
  • Use a LAN cable to connect between PC LAN port and instrument LAN port. 
Figure 2: Instrument LAN port

  • Open your PC's Local Area Connection and click Properties.
  • Select Internet Protocol (TCP/IP) and click on Properties.
  • Select Use the following IP address and fill it up with the following details (leave the rest as default):
    • IP address:
    • Subnet mask:
    • Note: You can choose any IP address and Subnet mask that is relevant to your network, but in this case we will use the typical 192.168.1.x and
  • Access the UTILITY MENU on the instrument by pressing the front panel keys [Shift] > [Utility/ Data Log].
  • Once you are in the UTILITY MENU, use the [arrow keys] and [Enter] button to navigate.
Figure 4: Use [arrow keys] and [Enter] to navigate
  • Press [right arrow] until you see REMOTE I/O. Then [Enter].
  • Select LAN and [Enter].
  • IP ADDRESS: (use the up-down arrow to change the number)
  • HOST NAME: (blank)
  • You should see a prompt saying "RESTARTING LAN"
  • Go back to your PC and launch a web browser. 
  • Submit (instrument's address) on the address bar.
  • You should see the instrument's Web interface homepage as below. 
Figure 5: Instrument's Web interface homepage

  • Click on Browser Web Control at the sidebar to access the control interface for the instrument. The default would be to observe the current instrument state. In this mode you can observe only. No changes can be made to the instrument.
Figure 6: Observe Only mode

  • To control the instrument, select the Allow Full Control radio button and have fun playing around! Besides setting the instrument state, you can also do store/recall and send commands.
Figure 7: Allow Full Control mode 

  • Other menu selection on the sidebar allows you to modify that LAN configuration, view the system status and  print display.
Figure 8: View system status

This is just an example of how to access a Web interface built inside an LXI instrument. Different manufacturer and instrument model may have slightly different way but it should not vary too much since it is based on Ethernet standards. The key is to treat it as if you would treat another PC, router or modem on your LAN network and you should be able to make the connection.