Product Description:

The 3EX45062 is a fieldbus communication module manufactured by B & R Automation and supplied within the System 2005 Controllers series. It installs on the controller backplane to provide a dedicated master interface that handles cyclic data exchange between the CPU and distributed I/O stations. By managing process data over an external network, the module allows the base controller to concentrate on application logic while delegating device addressing and token-handling tasks to the board.

For setup, the module is accessed through a configuration port that provides one RS-232 communication channel at a fixed 9600 bps. This service channel has no isolation and shares a 9-pin D-Sub housing with the field diagnostic LEDs. On the plant network side, the board acts as a PROFIBUS DP master and connects to the segment through the same connector. The actual fieldbus signals are carried on one galvanically isolated RS-485 channel to block ground loops. Data rates can be selected up to 12 MBd, enabling deterministic exchange of up to 512 bytes of input data and an equal block of output data per scan. At peak speed, the ASIC can supervise 125 subordinate stations while the assembly draws only 5.5 W from the controller's 5 V rail.

Internally, the card holds a dual-port RAM that mediates between the controller backplane and the PROFIBUS ASIC. The DPR dedicates 1 KB to cyclic control flags and status words, while another 2 KB stores process variables exchanged with the network. These buffers are managed directly by the embedded ASPC2 chip, reducing controller overhead and keeping the most recent field data accessible within one backplane cycle. Because the board relies on shared memory rather than interrupt-driven transfers, jitter on time-critical tasks inside the System 2005 CPU remains minimal.