The key to unlocking the benefits of this approach to automation project execution is in the flexibility of the I/O hardware. Each I/O channel can be individually characterized using a plug-in hardware module, providing the freedom to mix I/O types whenever necessary. Application programming can take place off-site at the same time as hardware configuration, with users able to configure and test I/O in the field without the need for the control application software or process controller hardware, while application software can be dropped in near the end of the project. By standardizing the cabinet, the need to run new cables for each and every sensor is reduced, and users no longer need to worry about certain sensor signals ending up in certain cabinets, as they can be terminated into any equivalent cabinet. This also helps to reduce space requirements as well as the volume and complexity of cabling. Hardware can essentially be shipped pre-wired, with the application software dropped in later, while testing can take place in the factory rather than in the field. For larger projects with potentially thousands of I/O points, this can make a huge difference to project time and costs, while for smaller projects, the cabinet no longer has to be installed in a specific location, and can for instance be installed in the field as opposed to in the control room, optimizing space even further.
Applications are programmed using a cloud-based deployment environment, which can be configured via a single laptop without having to access the physical cabinet hardware. Software checks can be tested virtually against emulated hardware and a simulated process to ensure that the code will perform as anticipated. Again, this can take place off-site, streamlining the process once the hardware and application meet up on-site. Both the software and hardware are configured using the same unique signal names, with digital marshalling automatically converging the application engineering project with the field I/O configuration once the two are connected on-site. This removes the need for space-consuming marshalling cabinets, while also potentially helping to facilitate any late changes required. In addition, the users have access to the application software much earlier than the traditional project execution and hence application testing can be done in iterations avoiding last minute surprise.
ABB’s System 800xA includes an Ethernet I/O Field Kit software, which allows users to configure and test I/O in the field without the need for control software or process controller hardware. The Field Kit runs on a normal laptop or tablet, and can be used for on-site commissioning activities where the I/O is already installed in the field, or split-staging arrangements where the I/O cabinets are located in a panel shop or fabrication yard. In practice, the software can reduce engineering time by more than 90 percent.