The PROFIBUS-DP bus coupler is designed to connect a PROFIBUS bus to TB20 peripheral modules. It supports the DP-V0 and DP-V1 protocols. 
It will recognize all connected peripheral modules and assign each module the corresponding inputs/outputs from the process image table.
A functioning TB20 configuration will always require a bus coupler and at least one peripheral module, but can accommodate up to 64 modules of any kind connected in series with the bus coupler. The bus coupler supports hot-swap for replacing modules during operation.

Bit packing:
Starting with firmware version 1.20, the states of 2-bit and 4-bit I/O modules can be packed together in bytes, making it possible to take full advantage of all the space in the process image table.

Parameters

• Diagnostic alarm: On | Off
• Process alarm: On | Off
• Pull/plug alarm: On | Off
• Startup when expected/actual configuration differ:  On | Off  (hot-swaping allowed: Yes | No)
• Identifier-related diagnostics: On | Off
• Submodule status: On | Off
• Channel-related diagnostics: On | Off

• Modules can be replaced during operation (hot-swapping)
• 24 VDC power supply
• Integrated power supply unit for powering peripheral modules (2.5 A)
• Supplies the system’s I/O voltage (24 VDC)
• USB device port for online diagnostics, configuring parameters, setup, and firmware updates with TB20 ToolBox
• TB20 ToolBox simulation for setting up the I/O system without a higher-level controller in order to test the system`s operation (I/O check)
• PROFIBUS DP slave as defined in EN 50170/IEC 61158
• Supports all PROFIBUS baud rates
• DP-V0 and DP-V1 support
• Up to 64 peripheral modules
• Up to 244 bytes of input data and 244 bytes of output data
• One class 1 master connection with 240 bytes of payload data
• Up to three class 2 master connections with 240 bytes of payload data (as a DP-V1 slave)
• I&M data
• 3 LEDs, one of them bi-color 
• Concealed "factory reset" switch for restoring the module to its factory settings