Who has not spent long hours setting up a new IT device in a private environment? Either the hardware is not compatible with other devices and the right adapter has to be found, or the devices speak a different language and communication is only possible with the right drivers. Even if you get the device working, you have already had to invest a lot of time, money and nerves. In industry, this means that integrating machines into a line involves an incalculable risk and/or incalculable costs. How you can minimize this risk?
Digitalization and flexibilization of production are making the functionality and architecture of machines and systems ever more complex. At the same time, demands on data provision and processing are also increasing: Automation has to work more closely with MES/ERP and cloud systems, process the corresponding data and preprocess the production data so that they can be used for documenting and analyzing processes and products. Machines and systems are being used in a greater number of ways and have to be capable of manufacturing various formats, quantities and even completely different products with minimal retooling times. Consequently, in future the simulation and verification of machine and system behavior will become more important and also more complex in respect of both production and data.
Specifying and implementing standards for communication
The first step toward making this complexity manageable is to standardize the communication, both between the machines in the production area and with the higher level IT systems. Engineering standards also help to reduce the cost of integration and make the overall solution open and expandable – which is important, for example, for later modifications. To make sure that machines and systems work together smoothly during commissioning, plant operators should specify an appropriate communication standard – ideally in the requirement specification so that the technical requirements can already be correctly implemented during the planning. Either one’s own standard can be specified or existing standards can be applied.
OPC UA is one such communication standard. Communication via OPC UA functions independently of the particular platform or the automation system being employed, provided that the participants conform to the current specifications of the OPC Foundation. In addition to these specifications, several companion specifications have been established over the last few years. These specify OPC UA communication for specific industries and applications. Together with the Foundation, the Organization for Machine Automation and Control (OMAC) has published the OPC UA PackML Companion Specification for the packaging industry. The VDMA and the OPC Foundation are currently working on a companion specification for robot applications. Together with PROFINET International, the Foundation is developing a companion specification for safety communication via OPC UA and Profisafe. Most suppliers of automation solutions also support OPC UA, so this is also suitable as a standard for communication between devices and higher level systems within production lines.
The specifications for OPC UA communication have been implemented in Simatic S7-1500, so the corresponding specifications can be loaded at a later stage with the aid of an external tool. In the current version, these controllers can act as both servers and clients. The Simatic S7-1500 OPC UA server and client enables the implementation of standardized interfaces based on the corresponding OPC UA companion specification, such as OMAC PackML or the EUROMAP specification for injection molding machines. Siemens supports the configuration of the corresponding functionality in the Simatic controllers in TIA Portal with corresponding wizards, so the user only has to program a few functions manually. The Siemens OPC UA Modeling Editor (SiOME) offers the option of using drag-and-drop to link interfaces to data from the controller. This enables the user to configure an application based on SIMATIC S7-1500 in TIA Portal. This can then be used to control a complete line according to the standardized OMAC status model.
Standards support engineering and commissioning
Powerful tools have become available for configuring machines efficiently.
However, to ensure that a new or modified line achieves the required performance, plant operators should also place importance on a standardized architecture and standardized tools for engineering. Better transparency also simplifies verification of the planning on the basis of models, which substantially reduces the time required for coordinating and optimizing the line.
Plant operators can validate and optimize the functionality and performance of their lines with simulation tools such as Plant Simulation during the planning stage. At the same time, the line integrator can start developing the line control and also test and validate his solution with the Simatic S7-PLCSIM Advanced virtual controller, without the individual machines having to be physically available. While this is happening, each machine manufacturer can generate a digital twin, that is to say a digital representation of his machine. This virtual machine can be controlled by a virtual controller, such as the Simatic S7-PLCSIM Advanced, via an integrated interface and operated by simulated HMI devices. Because OPC UA is used as the standard for data exchange between machines and the system, all sequences and material flows can be simulated and optimized with appropriate simulation tools before actual commissioning takes place. Plant operators, integrators and machine manufacturers can all continue to develop their own solutions in parallel while using information from the overall project at the same time. The functionality and interaction of the machines can be tested and validated in advance on the model so that verification of whether individual machines and the conveyor units work together as planned can be obtained during the planning phase.
Acceptance of machines installed at individual machine manufacturers to expand or modernize production facilities takes place at the Siemens factory in Amberg. For the test run, the machines on site are connected to the Siemens factory in Amberg via standardized interfaces, allowing them to process real orders from the factory. Adaptations and adjustments are made on the premises of the machine manufacturer, so that they do not block any valuable production facilities, and the machine manufacturer has all his personnel and know-how on the spot.
Additional advantages during run-up and operation
Standardized communication and tools for simulation and modeling do not merely support the phases up to commissioning. The digital twin of the finished production line can also be used to train plant operators and service engineers. Employees can be trained in advance on the virtual line with real or simulated HMI devices and the machine model, thus speeding up the production ramp-up and shortening learning time on the line. Plant operators should therefore define appropriate standards for visualizing systems at an early stage. Siemens has developed a new visualization system for machine-level operator control and monitoring right through to SCADA applications at line level. Thanks to web technologies, this system can be used irrespective of the device used and the current location. With the support of IoT systems and technologies, WinCC Unified connects SCADA to MES and IT so it can be used as an integration platform on production lines.
Faster feedback for modernization and optimization services
Simulating processes with a digital twin also helps to speed up feedback processes. It allows feedback from the operators undergoing training to flow back into the development of the solution during the engineering phase, for example to optimize the user interface. During the operational phase, the plant operator can use the model to run through variants when assigning parameters or designing the line – in order to increase the clock rate or identify the optimal solution for an expansion or conversion. And, as the plant operator has already specified the corresponding interfaces, he can be sure that a new machine will integrate well into the existing line. In this way, standards and uniform tools also help to protect investments in machines and plants.
The early definition of standards enables engineering tasks to be performed in parallel and results to be tested and validated virtually. This saves valuable time in commissioning, and production can be started earlier. In industry, as in private life, it saves a lot of time, money and nerves if machines do what they are supposed to do as soon as they are “plugged in” (plug & work).