Product Description:

The 3EX450.66 communication module is supplied by B&R Automation as part of the System 2005 Controllers series. Mounted on the controller backplane, this unit equips the CPU with a dedicated fieldbus master so that distributed drives, remote I/O racks, and safety devices can be polled over a single cable. By acting as the central arbitrator on a PROFIBUS network, it simplifies wiring, lowers response latency, and enables coordinated motion or process control across large-scale automated equipment with fewer point-to-point links.

As a modular master, the card supports the PROFIBUS DP master protocol and can push telegrams at up to 12 Mbit/s; this ceiling sets the shortest possible scan time for time-critical machines. A dual-port RAM of 2 KB handles buffers between the fieldbus ASIC and the CPU, helping prevent cycle jitter. The controller can address as many as 125 slave stations, which permits lengthy conveyor lines or multistation cells to share one segment. Per bus cycle, it receives 512 bytes of input data and returns the same amount as output, giving symmetrical bandwidth for sensors and actuators. Cabinet heat rise is moderated by a load of 5.5 W. Field wiring attaches through two 9-pin D-Sub connectors: IF1 is an RS-232 service port without galvanic isolation, while IF2 uses an isolated RS-485 driver, which separates maintenance traffic from process traffic.

The module remains fully operational from 0 to +55 °C, matching the temperature range used in most control cabinets. Service laptops connect through the service port at a fixed speed of 9600 bit/s, a rate that helps maintain reliable RS-232 communication over short cabinet-level cable runs. On the PROFIBUS side, an ASPC2 chipset manages token passing, watchdogs, and diagnostic counters so deterministic transfers persist even at segment limits. This arrangement supports stable data exchange when the network includes many nodes and mixed device types.