Introduction to the 6ES7138-4FA05-0AB0 Failsafe Module
The Siemens 6ES7138-4FA05-0AB0 is a crucial component in industrial safety systems. It’s a failsafe digital input module designed for the highly reliable SIMATIC ET 200S distributed I/O system. Its primary role is to safely acquire signals from safety sensors like emergency stop buttons, light curtains, and safety gate switches, and transmit them over a PROFIBUS or PROFINET network using the PROFIsafe protocol.
The Siemens 6ES7138-4FA05-0AB0 is a failsafe digital input module (F-DI) for the SIMATIC ET 200S I/O system. It provides 4 or 8 channels of 24V DC inputs suitable for safety applications up to SIL 3 (IEC 61508) and PL e (ISO 13849-1), communicating via the PROFIsafe protocol.
Core Functionality and Application
This module is the bridge between your physical safety devices on the plant floor and your safety PLC (F-CPU). It constantly monitors the state of connected sensors. Unlike standard I/O, it has built-in diagnostics and redundancy to ensure that any failure (like a wire break or short circuit) results in a safe state. It can be configured for either 8 single-channel (1oo1) sensors or 4 dual-channel (1oo2) sensors, making it flexible for various safety task requirements.
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Technical Specifications: 6ES7138-4FA05-0AB0
Accurate specifications are critical for system design and maintenance. Here are the key technical details for this module.
| Specification | Value |
|---|---|
| Product Type Designation | F-DI 4/8x24VDC PROFIsafe |
| Supply Voltage (Rated) | 24 V DC |
| Permissible Voltage Range | 20.4 V to 28.8 V DC |
| Number of digital inputs | 8 (in 1-out-of-1 evaluation) / 4 (in 1-out-of-2 evaluation) |
| Input Voltage for Signal “1” | 15 V to 30 V DC |
| Input Voltage for Signal “0” | -30 V to +5 V DC |
| Safety Integrity Level (SIL) | SIL 3 (acc. to IEC 61508) |
| Performance Level (PL) | PL e (acc. to ISO 13849-1) |
| Communication Protocol | PROFIsafe |
| Required BaseUnit | e.g., 6ES7193-4CA40-0AA0, 6ES7193-4CA50-0AA0 |
| Dimensions (W x H x D) | 30 mm x 81 mm x 52 mm |
The SIMATIC ET 200S system is a mature product line. While fully supported and widely used, Siemens recommends the newer SIMATIC ET 200SP system for all new machine designs and projects. The 6ES7138-4FA05-0AB0 is ideal for spare parts, repairs, and expansions of existing ET 200S installations.
Frequently Asked Questions (FAQ)
What is the difference between 4-channel and 8-channel mode?
The module’s configuration depends on the sensor wiring. Use 8-channel mode for eight separate single-channel sensors (1oo1 evaluation). Use 4-channel mode for four dual-channel sensors (1oo2 evaluation), such as an emergency stop button with two redundant contacts. The 1oo2 evaluation provides higher diagnostic coverage and is common for achieving higher safety levels.
Can I use this module with a standard S7-1200 or S7-1500 PLC?
You can only use this failsafe module with a safety-rated PLC, also known as an F-CPU. This includes models like the S7-1200F, S7-1500F, S7-300F, or S7-400F. A standard PLC cannot process the PROFIsafe communication protocol required to ensure safety functionality.
What BaseUnit is required for the 6ES7138-4FA05-0AB0?
This electronic module requires a specific ET 200S Terminal Module (BaseUnit) to function. You must use a BaseUnit that supports power distribution, such as the 6ES7193-4CA50-0AA0 or 6ES7193-4CA40-0AA0. Using an incorrect BaseUnit will prevent the module from operating correctly.