The Weidmüller SAI-AU M12 SB 4AI is an analog input module for decentralized sensor/actuator systems in industrial applications. It is designed for transmitting analog signals via a subbus and features four analog inputs. The module is part of the SAI Active product family and connects to the higher-level system via an M8 subbus connector. I/O connections are made through four 5-pin M12 female connectors, which are A-coded to ensure a unique and secure plug connection. The operating voltage is 24 V DC, with a supported voltage range of 18 to 30 V DC. An integrated reverse polarity protection safeguards the device against incorrect connections. The IP67 protection rating makes the module dust-tight and waterproof, allowing use in outdoor environments or humid conditions. The enclosure is made of Pocan and PBT materials, known for high mechanical robustness and resistance to aggressive chemicals, vibrations, and temperature fluctuations. The UL-94 flammability class 5VA indicates the high flame resistance of the enclosure.

Applications
This module is designed for decentralized applications in industrial automation, particularly in environments with high mechanical and chemical stress. It is suitable for integrating analog sensors—such as pressure sensors, temperature sensors, or level measurement devices—into existing SAI systems. Its robust design and IP67 protection rating enable use in production facilities, conveyor systems, or process engineering, where high demands for reliability and environmental resistance are required.

Functions and Features in Detail
The module features four analog inputs connected via 5-pin M12 female connectors. Signals are transmitted to the higher-level system via the subbus, which is implemented using a 4-pin M8 male connector (input) and a 4-pin M8 female connector (output). The A-coding of the connectors prevents incorrect connections. The 24 V DC supply voltage is provided via the subbus, with support for a voltage range of 18 to 30 V DC, enabling flexible integration into existing power supply systems. The integrated reverse polarity protection safeguards the device against damage from incorrect wiring.

Technology Explained Simply
The IP67 protection rating means the device is completely dust-tight and protected against temporary water ingress, such as from splashing water or brief submersion. This makes it suitable for use in damp or wet environments. The materials Pocan and PBT are thermally and chemically resistant, increasing the module’s lifespan in demanding industrial environments. The UL-94 flammability class 5VA indicates that the enclosure is highly resistant to ignition and will not self-ignite in the event of a fire.

Compatibility and Accessories
The module is designed for use in Weidmüller’s SAI system. Compatible accessories include the protective cap SAI-SK-M12-UNI 2029, which protects the M12 connectors from contamination and mechanical damage, and the device marker ESG 8/13.5/43.3 SAI AU, used for clear identification of the module. The protective cap SAI-SK M8 is intended for the M8 subbus connectors. These accessories are optional and not included in the standard delivery.

Mounting and Installation
The module is integrated into the existing SAI system via the M8 subbus connector. The M12 female connectors allow direct connection to analog sensors. Mounting is typically done on a wall or in an enclosure, taking into account the dimensions of 155 × 30 × 32 mm and a weight of 274 g. The operating temperature range is 0 to 60 °C, and the storage temperature range is −25 to 85 °C. Installation requires no additional tools, as the connectors are standardized.

Operational Advantages
The module provides a reliable and robust solution for decentralized analog signal acquisition. The IP67 protection rating and high-quality materials ensure a long service life even in demanding environments. The integrated reverse polarity protection reduces the risk of incorrect connections. Compatibility with Weidmüller’s SAI system enables easy integration into existing automation infrastructures. The CE and cULus certifications confirm compliance with European and North American safety standards.