The best production machines do not deliver the desired benefits if they are not controlled efficiently or cannot be operated intuitively. When ASML, one of the world's leading suppliers of lithography systems for the semiconductor industry, developed new machines for the assembly of pellicles, the company equipped the prototype with an equally prototypical PLC program that did not meet the requirements of a series machine. The problem: the control software was not robust enough. In addition, as with most prototypes, it offered neither maintenance functions nor the necessary stability.

The choice for the PLC programming fell on the Cordis Suite, with which the PLC program is modeled in UML (Unified Modelling Language) instead of classically programmed. ASML opted for Visiwin from Inosoft to create the machine HMI. Thanks to its modular structure and open .NET architecture, the software can be flexibly adapted: Users can fall back on pre-programmed functions, but still have enough options to tailor the system to their own needs.

In the course of the project, a link was created between Cordis Suite and Inosoft Visiwin, in which definitions from the low-code model of the PLC program are automatically transferred to the HMI project.

Low-code approach reduces programming effort

The Cordis Suite software follows the low-code approach. This means that the user focuses on the architecture and design of the programs by creating a model with the help of a graphical editor. This enables the result-focused development of complex applications without having to write a single line of code. The software then takes over: it translates the graphical model into the relevant code for the various PLC systems. In this way, the software significantly reduces the programming effort compared to the conventional approach.

The aim of the software is to provide everyone involved in the development process with a platform that they can work with, regardless of their programming skills. The Cordis Suite is vendor-neutral. It can be used to generate code for the PLC systems of many different suppliers, for example for controllers from Bosch Rexroth, Beckhoff or Siemens.

The decision to use the Cordis Suite software together with Visiwin was based on the intuitive operability of both platforms, regardless of the user's previous knowledge. However, the basic connection for seamless working with both tools was still missing. ASML also wanted an efficient engineering process with automatic transfer of definitions from the low-code model of the PLC program to the HMI project. The aim was to avoid error-prone additional work as far as possible.

Automatic transfer of variables

To achieve this, the software experts developed a communication driver that links Visiwin with the Cordis Suite Platform - the technical basis for the Cordis Suite. The communication driver establishes a bidirectional connection so that the data contained in the low-code model is also available in Visiwin. This involves certain values such as speed or temperature. Once the model has been created and Visiwin is to be connected, the export mechanism, which is now firmly integrated into the Cordis Suite, automatically generates all relevant definitions for Visiwin. The project planner of the HMI only has to create his screen pages and, for example, link a pointer instrument with a variable from the model via a selection dialog.

In addition to the variables, the Cordis Suite Platform transmits even more information, including alarm definitions. For example: If an accident prevention door is opened, the machine must react automatically and stop immediately. This is defined as an alarm in the Cordis Suite and then exported to Visiwin, as the HMI software, as the interface to the user, must of course be aware of the alarm.

Users can also use the HMI to call up certain commands that were previously defined in the Cordis Suite. These so-called 'commands' can be assigned to any buttons or similar elements in Visiwin. This means that the operator presses a button and a corresponding action is triggered in the PLC. These commands are also transferred to Visiwin via Cordis Suite Platform: this ensures that both systems are consistent and always work with the same definitions, making the low-code model a "single source of truth" for the PLC and HMI.

Managing complexity

Users of the new Pellicle machines benefit from seamless integration between the control software and HMI. And the link also brings great benefits for ASML itself: Thanks to the low-code approach, everyone involved in the development of the machines - from software specialists to function architects and mechatronics engineers - was able to work together intuitively. There were no communication problems because the sequence for the machine functions is displayed graphically. This is a great advantage over the previous work in code, the function and sequence of which everyone involved had to analyze individually in their heads. This is often a particular challenge for those who do not regularly read program code - especially as each programmer has their own style.

The author: Stefan Niermann is a sales engineer at Inosoft in Hiddenhausen.

© Inosoft

One advantage of the low-coding approach is that you no longer have to deal with the code itself, but only with the design of the program. If adjustments are subsequently required, the links in the graphical model are modified. This makes it easy to manage great complexity with the help of low coding. In addition, the graphical representation makes the program easier to understand, so that employees can familiarize themselves with the program logic more quickly.

The improved clarity of the model also significantly reduces the error rate, which can considerably reduce the effort required to program the PLC systems. According to ASML, the programming effort is now only around a third of the time compared to the previous machines.