Uniform visualization is an essential part of MTPs. The configuration of the human-machine-interface occupied the NAMUR task force for a considerable time during the definition of the common standard. “Machines used in process technology are usually designed for on-site operation, have their own controller, and a small display,” explains Tauchnitz. However, because process engineering systems are controlled by a central control panel, the goal cannot consist of controlling individual processes on site and monitoring them by hand. Most recently, the question has arisen regarding how machines from different manufacturers can be seamlessly integrated into centralized SCADA systems, and how to budget for the time-consuming programming tasks.
“You have to tell the module controller which values to export; then you have to tell the control system which data to import. This currently relies on the programmers writing long lists – with the goal of moving the necessary data transfer along,” reports Tauchnitz. If there are changes, then both sides of the program have to be adapted. “This is completely inefficient, because this work has to be redone for every new combination.”
The hidden additional costs become clear when considering visualization. Instead of using the data from the user interface of a system module for a central visualization, the on-site image has to be newly programmed in the SCADA system. In contrast, the MTP tells the central system which operating elements are to be displayed at which locations on the screen. “For example, a boiler is always in the center, and the temperature display is in the upper-right,” states Tauchnitz. The central system ultimately determines how the visualization should be configured. The MTP, for its part, specifies the framework for the process module to be displayed.
