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Datasheets and User Guides

App Notes

Software & Driver


26.0 HTTP Server

HTTP Server (Alpha)

Required firmware: 1.0136.


The T7 has a simple http server that can be used to display data or control the T7.

Web pages are stored in the User area of the internal flash chip.


Files that end in .htm or .html will be scanned for two tildes surrounding a list of parameters that make a Modbus command. When found, the command will be executed and the resulting string will replace everything enclosed in the tildes. The command is a set of parameters separated by commands. Refer to the following list for parameter definitions:
Parameter 1: The first parameter is the direction. R for read and W for write.
Parameter 2: The second parameter is the Modbus address.
Parameter 3: The third parameter is the data type. These numbers match the LJM constants in "LabJackM.h".
Parameter 4: The fourth parameter tells the T7 how to convert the value to a string.


SN: ~R,60028,2,1~

Here we are reading from address 60028 (serial number) data type is 32-bit unsigned integer and the string format is also 32-bit unsigned integer. The resulting string is:

SN: 470010531



The T7 will respond to ReST commands. The command format is /modbus followed by several parameters., direction (read or write), modbus address, length="number of registers", format=FormatIndex, value=X.XX (for writes only), custom="string"). The custom string is a printf instruction that will be used to change the result string is formatted.


Write Example:



Read Example:




At the moment only a handful of MIMEs are supported:

  • htm
  • html
  • js
  • png
  • css


Device Name:

When both the T7 and the computer requesting a web page are on the same network the NBNS can be used instead of an IP. Either the IP address or the device name followed by a '/' can be used to connect to the T7. Examples:




To send web pages to the T7 they must be packaged and then loaded into flash. Below are two proof of concept programs. One to package webpages and another to load them onto the T7.


Know Issues:

  • Images currently do not transfer properly.


File Attachment: