by Dr. Michael Hilgner, Manager Consortia & Standards, TE Connectivity
Results Made Available
On the 26th of November, the Industrial Internet Consortium (IIC) announced the publication of results for the Smart Manufacturing Connectivity for Brown-field Sensors Testbed run by IIC-member participants TE Connectivity and SAP SE, with supporting participants OPC Foundation and ifm electronic. The announcement refers to the IIC Results White Paper, “Smart Manufacturing Connectivity for Brown-field Sensors Testbed – Initial Deployment – Report after Completion of Phase I” by Dr. Michael Hilgner, Manager Consortia & Standards at TE Connectivity’s Industrial Business Unit, and Erich Clauer, Vice President, Industry Standards & Open Source at SAP, which had been released a few weeks ago. Some additional insights are provided by the article, “Results, Insights and Best Practices from IIC Testbeds: Smart Manufacturing Connectivity for Brown-field Sensors Testbed”, published in the IIC’s September issue of the Journal of Innovation. The information described in this article was captured in an interview conducted by Joseph Fontaine, Vice President, Testbed Programs at IIC with Dr. Michael Hilgner.
About the Testbed 
The testbed introduced a solution to extract data from the sensor data aggregation level underneath the governing Programmable Logic Controller (PLC) of a real-time control system and to make these data available to higher-level IT systems with a standardized semantics to enable the quick setup of added-value services. This solution is particularly suitable for brown-field installations where PLCs are often far from modern and cannot be burdened with data processing tasks beyond the original automation task they were once designed and selected for. However, advanced analytics and in particular, machine learning algorithms require a high volume of data which is delivered through an additional communication path established by a retrofittable hardware, the so-called “Y-Gateway”. This additional path bypasses the PLC and facilitates the “IoT data flow” in the figure to the right, whereas the performance of the real-time control system is not compromised.
Key Technologies IO-Link and OPC UA
The Y-Gateway is intended to substitute an IO-Link master gateway, a special I/O module which typically implements eight IO-Link masters to connect eight IO-Link devices, sensors and actuators with IO-Link interfaces, to the fieldbus or Industrial Ethernet, respectively. Any IO-Link device is delivered with a set of files in XML format constituting the IO-Link Device Description (IODD) which contains a variety of information for the system integration and which is used for configuration purposes. The general structure of the IODD defines a semantics which is the basis for a consistent IO-Link/OPC UA conversion implemented on the Y-Gateway.
The additional communication path established by the Y-gateway uses OPC UA which allows for the exchange of information models of any complexity and thus enables semantic interoperability. The Y-Gateway performs the conversion of the IO-Link sensor data to an OPC UA information model and implements an OPC UA server to allow for OPC UA clients to access these data.
The IO-Link/OPC UA conversion has recently been standardized in a joint effort of the IO-Link Community and the OPC Foundation. The IO-Link/OPC UA Companion Specification extends the set of available standards which define OPC UA language extensions for specific data sources. Companion standards for devices are based on IEC 62541-100, which provides a top-level device base-type and an associated event base-type.
Connecting to the Platform
For communication with the enterprise or cloud platform level, SAP Plant Connectivity (PCo) serves as an OPC Client. PCo is designed to establish the connection to various platform solutions, each of which is suitable for a wide range of applications with diverse focuses. Within this testbed, two platform solutions were connected, and associated data models were implemented:
- SAP Manufacturing Integration & Intelligence (MII) is an SAP application for synchronizing manufacturing operations with back-office business processes. In many use cases it is configured as a data hub between SAP ERP and operational applications, such as a manufacturing execution system (MES) and provides analytics and workflow tools for identifying problems in the production process and improving its performance.
- SAP Cloud Platform is a platform-as-a-service developed by SAP SE for creating new applications or extending existing applications in a secure cloud computing environment managed by SAP. The SAP Cloud Platform integrates data and business processes.
Implemented Usage Scenario
A usage scenario was implemented for validation purposes where the testbed solution was applied to monitor the amount of compressed air consumed by a manufacturing sub-process and to
optimize the consumption per produced part. The setup includes two sensors, an IO-Link compressed air meter to measure precisely the air flow, consumption and the current temperature, and an IO-Link laser distance sensor to count the produced pieces and thus, to determine the produced volumes. The sensors are connected to a Y-Gateway that Performs the IO-Link/OPC UA conversion and provides the data via OPC UA to PCo, which then delivers them to either MII or SAP Cloud.
The consumed compressed air significantly varied over the produced parts. This finding could serve as a starting point for a deeper root-cause analysis to yield an increased overall equipment effectiveness and thus savings.
Conclusion
The testbed demonstrates a retrofit solution for brown-field manufacturing cells that allows for higher-level IT systems to retrieve a high volume of sensor data to enable advanced analytics and machine learning algorithms. The re-use of existing cabling and the use of a standardized semantics ensure minimum integration effort and thus minimum downtime. Insights into potential improvements and optimization opportunities can be already gained from analyzing the data from just a few sensors.
Additional Resources:
- IIC Press Release
- IIC Journal of Innovation, Sept. 2018
- IIC Testbeds
- IIC Testbed Demos Smart Manufacturing on PLC-based Equipment