By providing a digital twin that enables software-in-the-loop simulation, Siemens gives users the ability to simulate their PLC and HMI programs with an exceptional simulated model of the real physical machine. Users can apply this simulation for highly effective virtual commissioning, which allows issues to be identified early in product development, lowers the risks of real commissioning, and enables parallel work, along with a shorter time-to-market.
Manufacturing companies today face many challenges to ensure their long-term competitiveness. The competition is fierce and customer requirements are becoming more and more individualized, resulting in increasing complexity of machine design and longer and more expensive commissioning time. To be able to respond appropriately, plant operators have to shorten their time-to-market and become more efficient and flexible while maintaining or even improving their quality. So what should a company do beyond optimizing its normal automation processes?
The answer lies in digitalization and the intelligent use of data generated from a common base to form a digital twin. This is a virtual representation of the machine that can be used to evaluate different automation concepts in the early phase of a project, reduce the commissioning time and accidents on site, and even assist with advanced training for machine operators. Specifically, the use of a digital twin allows for:
- Validation of control logic and visualization
- Validation of interaction between controller and mechatronics of a machine
- Validation of interaction of various components in a machine, cell, or plant
Within Siemens’ Totally Integrated Automation (TIA) portfolio, we use STEP 7 and TIA Portal to simulate and test the controller functions right at the configuration and engineering stages, with no need for real hardware. We have a comprehensive simulation of the controller functionalities with PLCSim Advanced that allows connections to virtual models of machines and plant behavior via an open Application Program Interface (API).
Virtual models of the machine can be created with Siemens Mechatronics Concept Designer (MCD) software; these models are far more than just 3-D representations of the machine. Rather, the models can be animated to simulate the real behavior of the machine, controlled by the program running in the virtual controller via PLCSim Advanced. In addition, the MCD software contains a physics engine that can be configured to allow for the effects of gravity, torque, and friction on the machine and parts moving through the machine. The result is an exceptionally high-quality simulation of the machine.
This simulation can yield a number of powerful benefits, including:
- Improved quality via optimizing the controller project and machine functionality in a virtual environment
- Reduced time-to-market via parallel operation of mechanical and automation engineering, and less time for commissioning at the end-customer plant
- Greater flexibility in creating alternative control concepts in the design phase
- Reduced costs and risks because of reduced commissioning time and fewer faults during the real commissioning
A Genuine Breakthrough
“Over the last few years, the pieces have come together to make this advanced digital twin possible,” says Colm Gavin, digitalization sales specialist, factory automation, at Siemens. Before, users could animate the machine with real physical properties using Siemens NX software with MCD; but with the advent of PLCSim Advanced, the simulation is taken to a whole new level.
“Within the NX MCD software, once you configure a piece to animate, you can set up how the simulation will run,” explains Gavin. “But with PLCSim Advanced, you have a simulation of the real PLC that works beyond the TIA Portal and allows third-party devices to receive inputs and outputs in a program, creating software-in-the-loop.”
In this case, simulations aren’t being driven by the NX MCD software but rather by the inputs and outputs coming from the PLC in PLCSim Advanced. So in this simulation there is no hardware with the exception, of course, of a PC. A PLC program can be downloaded and monitored that can itself monitor the on-off states of the inputs and outputs in the real PLC program. This program can communicate to the NX MCD software, read in the inputs and outputs, and run the simulation model based on what the program is running in the PLC.
“The quality of the simulation achievable using this method is very high,” notes Gavin. “Users can simulate their PLC and HMI program with a very good simulated model of the real physical machine. It’s as close to a real digital twin as one can get.”
Software-in-the-loop is a much more flexible approach to virtual commissioning because it allows testing without hardware investment, can interface to a wide variety of models through PLCSim Advanced API, and allows simulation resources to be spread over multiple computers and personnel.
Concept Validation and Optimization
From a workflow perspective, the digital twin streamlines processes by allowing work to be done in parallel rather than sequentially. “Consider how projects are done,” recounts Gavin. “Typically it begins with design, goes to mechanical, then to electrical. Only after those sequential steps can the automation engineer test out the program, and often he is under intense time pressure by the time the work gets to that point. With the digital twin, the machine testing and commissioning is virtual, and the design can be proved out much earlier because the work can be done in parallel by all parties involved.”
Further, by optimizing the process, the risk reduction for real commissioning is minimized because evaluation of the machine under error conditions can be done before the machine is actually commissioned. Without virtual commissioning, unexpected problems can result in significant time, material, and personnel requirements that can be exorbitant. In contrast, with virtual commissioning, causes of errors can be eliminated beforehand, solution strategies developed, personnel trained accordingly, and replacement material planned for with accuracy. In the former case, the costs are literally incalculable; in the latter, they can be calculated with confidence.
For OEMs that are always striving for the synchronized development of mechanical systems and automation processes, leveraging the digital twin for virtual commissioning makes eminent good sense, particularly as the industrial world continues to pursue digital transformation.Have an Inquiry for Siemens about this article? Click Here >>