The Siemens 6ES7138-4FB01-0AB0 is a 4-channel digital output module for the ET 200S system, rated at 24 VDC with a per-channel output current of 2 A. It carries SIL 3 and Category 4 ratings. The module is 30 mm wide and draws 28 mA from the backplane bus plus 100 mA from L+.
The output stage is a current-sourcing switch with a minimum signal "1" voltage of L+ (-2.0 V) and a maximum voltage drop of 0.5 V on the sinking side. Each channel can handle resistive loads up to 30 Hz switching frequency, inductive loads at 0.1 Hz, and lamp loads at 10 Hz. The module detects wire-break (open load) and short-circuit conditions, with a load monitoring range of 12 Ω to 1 kΩ. Cable runs up to 200 m are permitted for both shielded and unshielded wiring. Current derating is specified per ambient temperature: 4 A maximum per module up to 40 °C, and 5 A up to 55 °C. The total module current is capped at 6 A. Power dissipation is 3.5 W typical.
Diagnostics and status indication
A group error SF (red) LED and per-channel green status indicators are provided. The module supports diagnostics functions, including wire-break and short-circuit reporting. Electrical isolation exists between the channels and the backplane bus, but not between channels themselves or between channels and load voltage L+.