4 digital inputs, 24 V DC, 15 mm slice
The Siemens 6ES7131-4BD00-0AB0 is a 4-channel digital input module for the SIMATIC ET 200S distributed I/O system, accepting 24 V DC signals from sensors and switches. It draws up to 500 mA from the supply voltage, with the actual load depending on the encoder type connected. The 15 mm width per module matters when you're packing I/O into a crowded cabinet — each slice takes up minimal DIN-rail real estate, and the 52 mm depth keeps the module within the standard ET 200S envelope.
Input characteristics and filtering
Signal threshold for a '1' is +11 to +30 V, with a typical input current of 8 mA at 24 V. The '0' signal range is -30 to +5 V, giving clean noise immunity on long cable runs — up to 1000 m shielded or 600 m unshielded. The input filter is parameterizable at 0.1 / 0.5 / 3 / 15 ms, letting you match debounce time to the sensor type. Minimum on/off transition time is 0.05 ms; maximum is 15.15 ms, so fast counting applications need the shorter filter setting. A hardware interrupt is available and parameterizable — useful for capturing time-critical events without polling the input image.
Protection and diagnostics
Electronic short-circuit protection is built in, with module-by-module shutdown of outputs to ground. The short-circuit diagnostic can be enabled or disabled per module, and diagnostic information is readable via the backplane bus. Reverse polarity protection on the supply input prevents damage from miswiring. Isolation between channels and the backplane bus is tested at 500 V DC, though there is no channel-to-channel isolation. A green status LED per input gives visual confirmation, and the group error SF (red) LED signals module faults. Power loss is 0.7 W typical.
The 6ES7131-4BD00-0AB0 occupies 1 byte of address space in the ET 200S backplane and draws up to 10 mA from the 3.3 V DC backplane bus. It accepts 2-wire sensors with a permissible quiescent current up to 1.5 mA.