Module Overview
The Siemens 6ES7138-4FB04-0AB0 is a SIMATIC DP electronic module for the ET 200S distributed I/O system, providing 4 transistor digital outputs. Each output is rated at a nominal 2 A (permissible range 20 mA to 2.4 A), powered from a 24 VDC load voltage, with short-circuit protection and reverse-polarity protection absent from the load side. The module draws up to 28 mA from the backplane bus and typically 100 mA from the load supply when idle.
Output Ratings and Derating
Output current per channel is rated for 5 A or 4 A depending on temperature. Total module current cannot exceed 6 A. Switching frequency is application-dependent: resistive loads up to 30 Hz (symmetrical), inductive loads up to 0.1 Hz, lamp loads up to 10 Hz. The module includes wire-break monitoring for the output lines, detecting open circuits in the range 12 Ω to 1 kΩ.
Safety and Diagnostics
The module is certified for safety applications to SIL 3 and Category 4, with a group error LED (SF red) and per-channel diagnostics. Galvanic isolation exists between channels and the backplane bus; no isolation between channels. Maximum residual current for a '0' signal is 0.5 mA for both sourcing and sinking configurations.