From the hazardous area direct to the desktop

Hubert Dornberger

Panel PCs for process visualisation serve to indicate and display process data and to operate process machinery and equipment. There are manifold requirements for modern visualisation devices. They have to combine easy operation with high availability and maximum cost-efficiency throughout their entire lifetime. The Polaris panel PC series meets all of these criteria. The visualisation systems are approved for use in hazardous areas (Zones 1 + 2 as well as Zones 21 + 22). They are available with TFT colour displays in six different sizes and with different input surfaces. ”For machine builder BHS-Sonthofen, not only the size and features were decisive factors when it came to selecting a panel PC for a machine, but above all the fact that the devices can be integrated into modern communication structures easily and with optimum data security”, says Franz Lindl of Lindl & Karl in Affing, the control engi-neering consultant responsible for project planning, implementation and installation of the visualisation solution at BHS.

BHS-Sonthofen, a company that can look back on a long tradition with origins dating back to the German mining and industrial heyday, is meanwhile one of the world’s leading enterprises in the field of mechanical process technology. Mixing equipment made by BHS is successfully used in the production and processing of concrete as well as in numerous other applications in the construction and construction material industry. BHS crushing technology is found in mineral material processing and in the recycling industry. The company’s filtration solutions for continuous processes and batch production span a wide range of applications from the chemical and pharmaceutical sectors to food and environmental engineering. All machines and plants are characterised by high efficiency, a robust design and easy maintenance. To optimise these features even further, BHS was seeking a visualisation solution for a very complex machine that not only meets basic requirements but also supports modern communication functionalities and can therefore be integrated into a remote maintenance system. The Polaris panel PC 12.1“ was chosen as the most suitable human-machine interface.

The Polaris panel PC series made by Bartec consists of innovative visualisation systems for hazardous areas. All devices are approved in accordance with Atex II 2G Ex e q [ib] IIC T4 as well as for use in areas containing explosive dusts according to Atex II 2D tD A21 T80°C IP6X. The panel PCs are designed with the “q” (powder filling) type of protection. The electrical connections are laid via a terminal compartment that meets the requirements for the “e” (increased safety) and “i” (intrinsic safety) types of protection. Displays are available in six sizes: Polaris Control is suited for simple applications involving texts and small graphics. The 5.7“, 10.4“, and 12.1“ devices are optimal as human-machine interfaces for controlling simple machines as well as for operating more complex machines or simple plants. The 15“ and 19“ panel PCs and remote units are designed for controlling and operating complex plants.

BHS-Sonthofen opted for a device version equipped with a medium-sized graphic display – the Polaris panel PC 12.1“. It is optimally suited for operating more complex machines or simple plants in mechanical process technology, for example mixers, crushers, reactors, centrifuges or ball mills. “It is operated by means of function keys, cursor keys, LEDs and numeric and alphanumeric input keys“, Lindl explains. “Their quantity is such that all applications can be realised in a comfortable and easy way.“ As regards the computer technology, the Polaris panel PC 12.1“ additionally succeeds in transferring the visualizing and operating simplicity usual in safe areas to the hazardous area. The Intel Pentium M processor is noted for its high performance. Moreover, the device has sufficient hard disk memory to accommodate BHS’ customised applications. The Polaris panel PC 12.1“ has a pre-installed Windows XP Professional operating system, making it compatible with many different software packages such as customised software or other standard visualisation programs. BHS uses BMS-Graf-pro, the market-proven Bartec programming package, for on-site operation.

Visualisation projects are developed in BMS-Graf-pro. From there, they are transferred to the panel PC either via a Bartec USB memory stick or over Ethernet using an FTP protocol. The process connection is effected via Profibus DP. All popular PLC protocols like MPI, Modbus and RTU are also supported by the visualisation system. Within the standard solution, Polaris is a single-task application. “BHS wanted to take a further step forward and implement remote maintenance of the machine control and operating unit in hazardous areas from the remote office to the Internet“, Franz Lindl continues. The combination of Windows XP Professional and the BMS-Graf-pro-Runtime visualisation software for Windows XP permits on-site operation of the panel PC. The use of the VNC remote software facilitates access to the device over the Ethernet. After the connection has been established, a device log-in screen appears on the user’s display to allow remote intervention in the control sequence. A separate server is inserted to provide optimum data security. This server communicates both with the panel PC and with the PC in the remote office, while the transfer of the visualisation data takes place independently over a separate Ethernet/Internet connection. Lindl: “At predefined time intervals, the server assigns new IP addresses to both the Polaris panel PC 12.1” and the remote PC in the remote office. An external computer trying to intercept the communication will receive an address unknown message, in other words it is thrown out of the current session and barred from re-entering it.“

The remote maintenance application for BHS-Sonthofen was implemented successfully with the Polaris panel PC 12.1“. The XP Runtime developed for this purpose is considerably faster than the DOS version. When the data transfer over the Ethernet is complete, XP Runtime is started automatically. In the configuration with Windows XP Professional and remote over Ethernet, Polaris visualisation systems open up many new applications in hazardous areas.

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Polaris: the wireless communication

SPS/IPC/DRIVES 2008