In process plants, restrictions apply to the available power specifically in Ex environments. Most microcontrollers that include an Ethernet controller (MAC) draw too much power to be used in such environments. A specialized combination of low power microcontroller and external controller for process automation specific protocols such as Ethernet-APL will solve the power requirements.
Ethernet-APL is the standardized Ethernet Advanced Physical Layer (APL) for 2-wire data transmission. It is based on the Single Pair Ethernet (SPE) standard 10BASE-T1L as defined in the amendment IEEE 802.3cg-2019 and is specifically expanded for use in the process industry. It enables consistent and fast IP communication over long cable lengths (up to 1000 meters) from the field level to the control system, and meets reliability, security and safety requirements necessary for the operation in the field of process plants.
Ethernet-APL ensures protocol transfer and power supply via a single twisted-pair (2-wire) cable while providing protective measures for safe operation within hazardous areas. It is designed to support different installation topologies with optional redundancy or failover concepts. According to IEC specifications, it also supports the validation, installation and implementation of the safe operation of field instruments.
Ethernet-APL provides the Network Access Layer of the TCP/IP model, connecting to the higher layers of the model provided by SEGGER’s IP stack emNet. In combination with ultra-low-power microcontrollers, emNet offers maximum performance with minimal memory requirements and simple integration without configuration effort. It is capable of providing excellent network performance while at the same time also being highly efficient in terms of flash, RAM, and overall processing speed and is therefore a perfect match even for small, low-frequency ultra-low-power microcontrollers.