What is an open standard?

January 152016
What is an open standard?

Bill Lydon's Automation Perspective

By Bill Lydon, Editor

Identifying open standards and finding vendors that are committed to fully support open standards can be challenging. Efficiently achieving the vision of Industry 4.0, Industrial IoT, Smart Manufacturing, and other initiatives will require the use of COTS (Commercial Off-The-Shelf) technologies that are open architecture. The value of leveraging open technology has been proven over the years in a number of industries including computer, cell phone, digital photography, gaming, and software industries. In every industry there has been resistance to open systems until a majority of customers demand them from suppliers. The industrial automation systems and controls industry still has a long way to go.

Open Source Software

In the software industry, the most obvious criteria defining open architecture is open source. The industrial automation industry has been slow to follow this pattern, but it is starting to happen.  Two good examples are UPC UA and SERCOS.

OPC UA

In the industrial automation industry, a bright spot is the OPC foundation that provides an open-source suite of OPC UA clients and servers that are ready to run without any configuration, including:

  • A central dashboard application with built-in documentation allowing you to launch applications
  • Samples that demonstrate DataAccess, HistoricalData and HistoricalEvents, Alarms&Conditions
  • Documentation designed to teach the concepts of OPC UA as well as the included sample applications.

The software is provided through an open source MIT license that, as the license states, “grants permission, free of charge, to any person obtaining a copy of the software and associated documentation files to use the software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the software is furnished to do so as long as it includes a copyright notice and the permission notice.” More information.

In addition, the OPC UA Local Discovery Server (LDS), that provides the necessary infrastructure to publicly expose the OPC UA Servers available on a given computer, is available on a Reciprocal Community License. More information.

The primary driver for this is the participation of software companies including Microsoft and SAP that understand how to move technology adoption forward. This is already accelerating the inclusion of the technology with Microsoft committing to make OPC UA available at no cost for all version of Windows 10, including embedded.

SERCOS

The Sercos International trade association announced at the 2015 SPS IPC Drives in Nuremberg, Germany, that the Sercos SoftMaster will be made available under an open-source software license for general use. The license model will be based on that of the Sercos master library CoSeMa (Common Sercos API; sourceforge.net/projects/cosema/), which has already been available as open-source driver software since April 2009 and can be used both for hard-master and SoftMaster implementations. Using the Sercos III SoftMaster, applications may be implemented with an Ethernet controller eliminating the need for a Sercos III FPGA or an ASIC master component. The Sercos III hardware functions are emulated in host-based driver software. This was demonstrated at the SPS IC Drives show on a standard industrial PC using the tenAsys real-time software. With this implementation, real-time behavior is achieved for a large number of applications.

Some companies are already carrying out the first projects using the Sercos III SoftMaster in cooperation with Bosch Rexroth AG. For example, a packaging machine manufacturer is planning to convert its entire machine program to the technology in time for Interpack 2017. The Sercos SoftMaster is running in an industrial PC without special fieldbus hardware and without PCI slots to control machines, providing a lean control solution.

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Communications

Widely accepted open communication standard examples include the GSM (Global System for Mobile Communications), and the Internet Engineering Task Force (IETF) which created the first standards of SMTP and TCP/IP.

There are a number of industrial automation protocols that are defined by trade associations and run on standard unmodified Ethernet including Modbus TCP, EtherNet/IP, EtherCAT, POWERLINK, and PROFINET.

MQTT is an open OASIS standard and a machine-to-machine (M2M) connectivity protocol being used in Internet of Things applications such as Amazon’s AWS IoT offerings. This high-speed Ethernet transport is particularly interesting since it could be the basis for carrying real-time industrial protocols over standard unmodified Ethernet.

There is great interest in the Ethernet IEEE 802.1 TSN (Time Sensitive Networks) that should be released in 2017. A number of groups are looking closely at the standard including SERCOS International, ODVA, PROFIBUS and PROFINET International (PI) and OPC Foundation.

Integrated Development Environments (IDE)

There is no IDE for industrial automation that is equivalent to the software industry open source IDE. For example, Eclipse is one of the more popular software integrated development environments (IDE). Users can extend its abilities by installing plug-ins written for the Eclipse Platform, such as development toolkits for other programming languages, and can write and contribute their own plug-in modules. Released under the terms of the Eclipse Public License, Eclipse SDK is free and open-source software. An open source industrial automation control development platform is nowhere in sight. The closest development for industrial automation is the FDT Group frame application.

Pitfalls

One of the strongest characteristics of a solid open standard is seamless interoperability between products from multiple vendors. In the industrial automation world this is not always obvious since many industrial protocol standards allow vendor specific portions of the protocol. Some vendors implement unique features in their products using the vendor specific parts of the protocols. If these industrial automation vendors did fully support the open standard and were committed to the automation community, they would contribute these unique features for use in the open protocol standard.

Reality

The reality is that virtually every industrial plant has systems with multiple protocols. In order to create cohesive systems users install protocol gateways and special software drivers. Some control vendors are offering native interfaces integrated with their configuration software and controllers for efficiently handling multiple protocols.  Examples include DeviceNet, Profibus, EtherNet/IP, PROFINET, EtherCAT, and SERCOS. Native interfaces lower configuration labor and simplify lifecycle support.

Something I hear repeatedly from users are issues with suppliers that only have seamless integration with the vendors “flagship” protocols. This forces users who need to interface other network protocols into their systems to add gateways and bridging devices. Those devices require special configuration steps which increases application engineering labor and results in higher lifecycle support cost. This is an inward-focused philosophy and certainly isn’t meeting the needs of users.

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