A machine working with another machine in a factory.

Real-Time Communication Made Simple

By Conal Watterson & Brian Condell

Knowing that communication is key, this blog focuses on Industrial Ethernet and real-time networking, what it is, why we need it, and how it can be made simple. This fourth blog in our Remote IO blog series follows on from our previous blog, Getting Tight on Space.

Industrial Ethernet is a key Industry 4.0 technology that enables real-time communication. Realizing the benefits of deterministic communication involves discussion of how to support multiple protocols and software platforms while minimizing development time and solution size.

Using Industrial Ethernet with Remote IO modules

Industrial Ethernet allows controllers to access data and send instruction commands from PLCs to sensors, actuators, and robots dispersed across the factory floor. Industrial Ethernet aims to solve the main challenges of the existing fieldbus/4-20mA technologies, like interoperability, lack of scalable bandwidth, and lack of available power at the edge node. Ethernet supports more data bandwidth, with speeds of 100 Mbps deployed today, and the option of Gigabit speeds. Ethernet also has the benefit of its ubiquity and long-standing usage outside Industrial use, with the existing knowledgebase allowing for less training and faster commissioning.

Remote IO modules that are Ethernet-connected allow existing sensors and actuators connected via 4-20 mA and traditional digital IO, to be accessed via the Ethernet-connected automation control system, realizing the benefits of increased bandwidth, addressability, and digitization.

Real-Time Communication

The key difference between standard Ethernet and Industrial Ethernet, is Real-time, deterministic performance.  “Real-Time” or “deterministic real-time” describes communication that is employed when < 1ms cycle times are required. In non-real-time applications, if information such as a webpage is slow to update, the impact is minimal. Standard Ethernet is the best effort, so the packet may be there in microseconds or a minute, or may never get there, it could get dropped, depending on the traffic in the system, data corruption during transmission, etc, there are no guarantees.

Conversely, in a manufacturing environment, the impact of delayed updates can be high, from wasted materials to accidental human harm. This means that control applications need determinism in packet delivery and timing guarantees, to ensure the correct operation of the task or process at hand. The TCP/IP protocols for routing traffic do not inherently guarantee this level of deterministic performance.

Traditional Industrial Ethernet networks address this by adding latency control and real-time awareness to Ethernet. The challenge is that adding these features requires modifying almost all layers of the communication stack. Specifically, specialized hardware must be added to guarantee latency. This has resulted in several vendors developing independent solutions for the same problem, at the cost of adding a variety of specialized layers for PROFINET, Ethernet/IP, EtherCAT, etc.

Multi-protocol Industrial Ethernet with ADIN2299

With such proliferation of various Industrial Ethernet protocols, one flexible solution is to use a multiprotocol Ethernet Switch such as the FIDO5210 and the appropriate pre-certified communication stack. The ADIN2299 RapID Platform Generation 2 (RPG2) is a complete 2-Port, 100Mbps Multiprotocol Industrial Ethernet module, comprising two integrated Ethernet PHYs (ADIN1200), integrated FIDO5210 switch, and an ARM Cortex M4 MCU for the protocol stack. Depending on the system design requirements, these components can be placed individually into the design. However, as an off-the-shelf verified solution, RPG2 enables Real-Time Industrial Ethernet communication to be simply added to existing or new IO module designs, as well as field instruments.

 Figure 1 - ADIN2299 RapID Platform Generation 2 (RPG2) Solution Siz

Figure 1 - ADIN2299 RapID Platform Generation 2 (RPG2) Solution Size

Using the ADIN2299 brings many advantages, such as:

  • Complete fully tested off-the-shelf solution.
    • Tested and Verified Solution with Datasheet Specifications

 

  • Software
    • User downloads desired network software (PROFINET, EtherNet/IP, EtherCAT, POWERLINK, Modbus TCP) from Developer Portal and installs via host interface
    • Common software interface and host driver speeds integration

 

  • Ease of Deployment
    • Pre-certification speeds Time-to-Market

 

  • Ease of Upgrade
    • No changes are required to host application code for protocol updates or changes.
    • Seamless transition to Embedded Reference Design in the future if needed for cost rationalization

 

  • Optimized Performance
    • Small footprint - 647 mm2
    • Low Power - 800mW

 Figure 2 - ADIN2299 Complete Software Solution

Figure 2 - ADIN2299 Complete Software Solution

This in turn brings some high-level benefits such as:

 Figure 3 - Benefits of using ADIN2299 Platform

Figure 3 - Benefits of using ADIN2299 Platform

References