Two fail-safe outputs, 2 A each, SIL 3 rated
The Siemens 6ES7138-4CF03-0AB0 is an ET200S fail-safe digital output module with two outputs, each rated 2 A at 24 V DC. It is certified for use in safety applications up to SIL 3 and Category 4.
Output current and temperature derating
Each output channel delivers 2 A rated current, but the total module current is temperature-dependent: 7 A up to 55 °C, dropping to 6 A at 40 °C and again at 60 °C. This means at 55 °C ambient you can run both channels at 2 A with headroom; above that, the total current envelope tightens. The module includes electronic short-circuit protection with a response threshold of 5 to 12 A for a short to ground, and 25 to 45 A for a short to P potential. It also detects wire-break conditions on the output lines.
Switching frequency and load types
Resistive loads switch at up to 30 Hz; inductive loads at only 0.1 Hz. The 10 Hz limit on lamp loads reflects the inrush current stress. For a solenoid or contactor coil, plan on a 10-second minimum cycle time. Cable runs can extend to 200 m, shielded or unshielded, which covers most cabinet-to-machine distances in a plant.
Diagnostics and status indication
The module reports a group error via a red SF LED, monitors the load voltage supply (PWR green LED), and makes diagnostic data readable over the backplane bus. It detects missing load voltage and short circuits, feeding that back to the safety CPU. Power draw from the backplane bus is 28 mA at 24 V DC; total module power loss is 4 W typical.