What the 8-channel digital input module does in an ET 200SP rack
The Siemens 6ES7131-6BF00-0AA0 is an 8-channel digital input module for the ET 200SP distributed I/O system. It reads 24 V DC signals from sensors or switches — P-reading (source input) — and packs them into 1 byte of process data for the backplane bus. Each channel draws a typical 6.8 mA at signal "1" (11 to 30 V DC), and the module's total power loss is 1.6 W when all 8 inputs are supplied via the encoder supply at 24 V. That thermal budget is low enough to pack modules tight in the rack without forced cooling.
Wiring and base unit compatibility
This module uses BU type A0 base units exclusively. For 3-wire sensors you need the AUX terminals on the A0 base unit.
Diagnostics and firmware handling
Diagnostic alarm and diagnostics function are built in — the module reports channel faults to the controller without polling. Firmware version V1.0 is field-upgradeable via the backplane. I&M data (I&M0 through I&M3) is supported, letting the maintenance system identify the module and its firmware revision remotely. Parameterization is enabled, so input filters and diagnostics can be configured in the hardware config.
No official successor or cross-reference has been published. The module is the standard 8-input 24 V DC option for the ET 200SP family — if your BOM calls for this order code, it is the current shipping variant.