Product Description:

B&R Automation's X20DS1928 module is part of the X20 Fieldbus Input Output Modules series and serves as a single-channel interface for absolute encoders in distributed motion systems. Mounted alongside CPU and drive modules on the X20 backplane, it translates serial sensor data into real-time position values for the PLC. Within automated packaging, robotics, or printing lines, the unit supplies precise shaft angle information so that axes can synchronize, execute coordinated moves, and detect position errors. Because it works with absolute encoder feedback, the controller can reference the actual shaft position directly instead of relying only on counted pulses during motion.

The channel has a resolution of 13-bit, permitting 8192 discrete positions per revolution from compatible sensors. Transmission uses a differential level of 1 VSS, which improves noise immunity on twisted-pair cabling. With the EnDat 2.1/2.2 serial protocol, the module handles position words, temperature data, and parameter downloads through a single bidirectional link. A regulated encoder supply of 5 VDC (±5%) is available and can deliver up to 300 mA for sensor electronics and integrated LEDs. The interface accepts differential, symmetrical inputs and operates with a maximum signal frequency of 400 kHz, enabling rapid sampling even at high spindle speeds. Serial signaling follows EIA RS485, which supports stable communication between the module and the connected encoder.

Signal integrity is maintained over cable runs up to 10 m, supported by an internal 120 Ω termination resistor at the receiver pair. The physical layer tolerates common-mode excursions of ±10 V, helping preserve data accuracy when grounds between machine sections shift. The housing carries an IP20 rating for installation inside enclosed cabinets, and the circuitry is overload-proof and short-circuit-proof to reduce the risk of accidental damage during wiring or startup. Electrical loading on the system bus is low, and the internal I/O electronics also draw little power, which helps limit heat buildup in densely packed control cabinets.