The BWU4068 is an ASi-5 motor module by Bihl+Wiedemann, designed to control 1 SEW MOVIMOT frequency inverter drive via RS485 in decentralized automation applications. Housed in an IP67-rated enclosure with M12 connectors, it eliminates the need for a control cabinet — mounting directly at the drive on the machine frame.

How does the BWU4068 communicate with SEW MOVIMOT drives?

The module uses RS485 at 9600 bit/s, with a process data image of 5 or 7 bytes compatible with the SEW PROFINET control profile. Cyclic speed setpoint and ramp values are written via 3×16-bit process output data, while motor current, status, and diagnostic information are returned via 3×16-bit process input data. Up to 100+ MOVIMOT units can be controlled over a single ASi-5/Ethernet gateway node.

What I/O does the BWU4068 provide alongside the motor channel?

In addition to the RS485 motor interface (X4, M12), the module provides 4 digital inputs across two M12 connectors (X1, X2) with switching thresholds at <5V low / >15V high, and 2 electronic outputs (X3, M12) sourced from AUX 24V. Output current per channel: 1A at +40°C, derating to 0.5A at +70°C. Sensor supply is drawn from ASi with short-circuit and overload protection.

What safety functionality does the BWU4068 support?

The module supports SIL/PLe safety integration via passive safe shutdown through the AUX power rail. Removing AUX voltage safely de-energizes the connected MOVIMOT drive without requiring a separate safety relay or contactor in the motor circuit — simplifying functional safety architecture for STO (Safe Torque Off) applications.

Where is the BWU4068 typically installed?

The IP67 plastic housing with clip or screw mounting allows direct machine-mounted installation — ideal for material handling conveyors, packaging lines, and logistics systems where decentralized drive control reduces wiring and cabinet space. Operating temperature range: -30°C to +55°C (up to +70°C with derating). The module is powered via standard ASi yellow (30V) and AUX black (24V) profile cables using piercing technology.