Difference between M12 A-code and M12 B-code types
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- Issue Time
- Feb 22,2025
Summary
In industrial automation and communications, M12 connectors are favored for their ruggedness, water and dust resistance, and support for a wide range of applications.
In industrial automation and communications, M12 connectors are favored for their ruggedness, water and dust resistance, and support for a wide range of applications. These circular connectors have different coding types to differentiate their use and pinouts to prevent mismating. Two common coding types for M12 connectors are A-coded and B-coded. In this article, we will take a closer look at the differences between these two coding types and their respective application scenarios.
M12 A Coded Connectors
The M12 A coded connector is one of the most popular and earliest developed M12 connectors and is widely used in sensors, DC power supplies, and 1G Ethernet connections. Available in 2-pin, 3-pin, 4-pin, 5-pin, 6-pin, 8-pin, 12-pin, and 17-pin configurations for a wide range of signal and power applications.
Pin count and application:
Pin 2 is typically used for simple switching signaling or low power supply.
The 3-pin and 4-pin models are primarily used in sensor and power applications.
Pin 5 is used for applications that require additional grounding or other auxiliary functions.
Pin 6 is used for specific multi-signal transmission requirements.
The 4-pin and 8-pin models are commonly used for Ethernet and PROFINET applications.
The 12-pin models are typically used for a variety of signaling applications.
The 17-pin is designed for extremely complex control and monitoring tasks and is able to integrate a large number of signal paths within a single connector.
Features:
Provides IP67 or higher protection to ensure reliable operation in harsh environments.
Supports Ethernet speeds up to 1Gbps for high-speed data transmission.
Widely used in industrial automation equipment, robotics, agricultural machinery and alternative energy systems1.
These extensive pin count options make M12 A-coded connectors ideal for a wide range of industrial automation solutions, from simple to highly complex.
M12 B Coded Connectors
M12 B coded connectors are designed for fieldbus connections and are particularly suitable for PROFIBUS and other similar industrial communication protocols.B coded connectors are typically available in 3-, 4-, and 5-pin configurations to meet the needs of complex industrial networks.
Pin count and application:
3-pin can be used for a simplified version of fieldbus communication under certain specific conditions.
4-pin is used for some of the less demanding data exchanges.
Pin 5 is the standard configuration of the M12 B-coded connector for PROFIBUS and Interbus fieldbus connections. It serves as a bridge between fieldbus components in the control cabinet and ensures stable and reliable data transfer performance.
Features:
Provides a highly reliable connection that maintains performance even in environments with frequent vibrations or large temperature variations.
Designed to focus on preventing misplugging and avoiding system failures due to incorrect connections.
Widely used in industrial control system data acquisition and monitoring system (SCADA), distributed control system (DCS) and other occasions.
In practice, 3-pin, 4-pin and especially 5-pin are the most common and standardized forms. B-code type connectors are designed for efficient fieldbus communication.
Key Differences Between M12 A-Code and B-Code Types
| Characteristics | M12 A Coded | M12 B Coded |
| Main applications | Sensors, DC, 1G Ethernet | PROFIBUS, fieldbus systems |
| Pin configuration | 2-pin,3-pin, 4-pin, 5-pin,6-pin, 8-pin, 12-pin, 17-pin, | 3-pin, 4-pin, 5-pin |
Data rate support | Supports up to 1Gbps | Mainly used for low-speed fieldbus communication |
Protection class | IP67 or better | IP67 or better |
Typical environments | Industrial automation, robotics, agriculture, alternative energy | Industrial control systems, data acquisition and monitoring systems |
Choosing the right coding type
The choice of M12 A-coded or B-coded connectors depends on the specific needs of the application. If your project involves sensor interfaces, DC power supply, or requires high-speed Ethernet connectivity, the M12 A-coded type may be a better choice. For industrial control systems that rely on robust fieldbus communications, the M12 B-coded version is more suitable.
Considering future technology trends, the demand for X-coded connectors for high-speed industrial Ethernet is growing and is expected to eventually replace A-coded and D-coded components as the standard for the next generation. Therefore, the possibility of technological upgrading should also be taken into account when planning long-term projects.