Product Description:

The X20DC1398 is a digital I/O module from B&R Automation and belongs to the X20 Fieldbus Input Output Modules series. It plugs into an X20 backplane and offers one high-speed digital input that can also serve as an incremental encoder channel. By translating field signals into deterministic bus data, the unit supports edge counting, speed measurement, and position feedback tasks in distributed industrial control systems. This makes the module useful for machines that need fast pulse evaluation at the field level while keeping control data synchronized with the PLC.

The input stage is rated for 24 VDC, so standard proximity sensors or limit switches can be wired without level shifting. Captured transitions are stored in a 32-bit counter, a depth that prevents rollover during extended production runs. When external timing is required, the module can export a clock signal while supplying up to 100 mA to downstream devices. Contact bounce is filtered by hardware that rejects pulses lasting 2 µs or less, ensuring only valid edges reach the CPU. Data is forwarded over the X2X link at up to 125 kbit/s, matching common PLC scan rates. A data input resistance of 18.4 kΩ minimizes loading on sensors, and the sink input circuit uses a 3-wire connection in accordance with EN 61131-2 Type 1. Only one logical input is present, simplifying address assignment. The combination of counting, filtering, and clock output allows one channel to handle sensor feedback and simple motion-related tasks without extra interface hardware.

For encoder service, the channel accepts 24 V asymmetrical signals and can provide 600 mA through its integrated supply to power the transducer. Module electronics draw just 0.01 W of bus power and need 1.3 W of internal I/O power, keeping panel heat generation low. A secondary input resistance of 7.19 kΩ governs current flow during differential counting on long leads. The housing carries an IP20 rating, so installation is limited to closed, dust-free cabinets.