Input characteristics and wiring
The 6ES7131-4BD01-0AB0: Input voltage thresholds are defined per the datasheet: signal "0" spans -30 to +5 V, signal "1" from +11 to +30 V. The module supports 2-wire proximity sensors, with a permissible quiescent current up to 1.5 mA — important when selecting sensors that leak current below that threshold to avoid false-on states. Reverse polarity protection is built in, and short-circuits to ground are detected module-by-module with electronic protection, configurable via diagnostics enable/disable.
Input filtering and timing
Input filtering is parameterizable to four settings: 0.1, 0.5, 3, or 15 ms. The corresponding transition times (min/max) scale with the filter setting — for example, at 0.1 ms setting the 0-to-1 transition is 0.05 ms min, 0.15 ms max. This lets the integrator match debounce to the sensor type: fast for encoders, slower for mechanical contacts. Cable length limits are 600 m unshielded, 1000 m shielded, adequate for most field wiring runs.