A new way forward – VisuNet

A new concept, named VisuNet, promises easier and more convenient exchange of visualization data between the ex zone in a process and non-hazardous areas.

The ex zone has always been a very special location, calling for extraordinary solutions. Pepperl+Fuchs is the specialist for devices, components and system solutions especially designed for hazardous areas. Located in Esslingen, Germany, up to 40 specialists are constantly looking for new ways to make things easier for the users of monitoring and control devices. Among the highlights are special HMI solutions to improve the man/machine interface. In this field, Pepperl+Fuchs has developed a new concept, called VisuNet. It promises easier and more beneficial interchange of information between the process area and the remote safe area, for example the control room. The modular concept comprises either a remote monitor (operator station) or, alternatively, a panel PC (as a self-standing on site device) in combination with optional interface components).

"The HMI market for the process environment is not a mass market but it demands long life, robust products," says Stefan Sittel, Business Development Manager at Pepperl+Fuchs, describing the general market situation. He adds: "Many products have been installed for more than 15 years and are still working perfectly." Up to three years ago, the technology of HMI components for the ex zone had not changed significantly. At this point, however, the former Extec GmbH introduced panel PCs for the hazardous area. With these very first panel PC solutions, it was possible, to operate complex visualization stations, equipped with PC-based SCADA software suites. These could be used either as a stand-alone system or in combination with other components as part of a multi-station system solution. As a neutral and open PC platform, the panel PC can be used as a machine terminal, as a client for visualization tasks, as a self-standing SCADA visualization station, as a soft PLC with a subsidiary remote station or as a server for subsidiary ThinClient stations.

It was a special client requirement that actually triggered the development of VisuNet. The customers wanted to place the hard disc and floppy disk drive outside the hazardous area. This called for a form of data communication that was both simple and dependable. The solution was realized with the RDP (Remote Desktop Protocol), a Microsoft protocol, which is an integral part of the Microsoft operating systems Windows Vista, Windows XP Professional and Windows 2003 Server; furthermore it is available for subsequent installation with the Windows 2000 Server. The protocol allows the setup of terminal services between two computer systems, where one system serves as a terminal server, which provides the other system (called the terminal client) with the information shown on the monitor. "What is special about the Pepperl+Fuchs solution is the fact that it enables the transfer of information via the Ethernet without the need for the previously required signal amplifier". This means, that with the help of an integrated Ethernet network interface, it is possible to connect the system into a higher-level network or as PC within a client-server structure.

Fast access to vital information

The basic version is called VisuNet RM (VisuNet remote monitor). This comprises remote control stations with 15" and 19" monitors for industries such as chemical and pharmaceutical, oil and gas, lacquer and paint processing and food. The data content of the monitor screen are transmitted in a simple and cost-effective way via a standard TCP/IP Ethernet network – making this solution ideal for machine control, the acquisition of operating data, process control and process monitoring. For these applications, VisuNet remote monitors replace conventional solutions, which use analogue signals and require signal amplifiers. It allows the operation of multiple PC remote operator stations connected to one central PC via network-based transmission technology. This opens the way for completely new concepts, including many advantages. For example, it is possible to access any PC within the network from a remote monitor.

Connecting to the desired host PC of the VisuNet remote is easy. Registration only requires the IP address, user name and password of the host PC. It is left up to the system project manager, whether he wants to connect the VisuNet remote monitors operator station to the host PC via auto start or prefers to use a special registration procedure activated via control buttons. In principle, all programs or applications installed on the server PC can be accessed. This includes SCADA systems, Office applications, MES applications (Manufacturing Execution Systems) and other PC applications.

The hardware and software of the remote monitor is kept to a minimum and operates as a thin-client. Thus the device functions can be cost-optimized, without the need for moving parts, such as cooling fans and hard disks. "The installations of our customers differ significantly, so that in addition to the operating station itself, we also offer devices with full PC functionality".

Depending on customer-specific requirements, the VisuNet family allows the use of a variety of alternative transmission media. Fiber-optic cables can be used to cover distances of up to two kilometers between the VisuNet remote monitor and the control system in the safe area. Pure Cat7 solutions are suitable for distances of up to 70 meters. Looping in and connection to existing Ethernet network topologies is possible at any time.

PCs with full functionality

If the user prefers a panel PC-based alternative, he may opt for one of the new devices of the VisuNet PC range with display sizes of 15" (1024x768 dots) or 19" (1280x1024 dots). They do not require any cooling fan and offer a 1.8 GHz Intel Pentium M processor in combination with 512 MB or 1 GB system memory and a 60 GB hard disk. Whether in combination with Windows XP, Windows 2000 or Windows 2003 Server, this neutral PC platform is powerful enough to even run any high-end process control system visualizations and SCADA applications with these operating systems.

VisuNet PC and VisuNet RM represent a modular system solution. While any system consists of the same core components – display unit, keyboard, cabinet and mounting technology (floor stand, wall mounting or ceiling mounting) – there are a number of options to allow the individual configuration of customer-specific solutions. Additional components, such as heating, cooling and a high-brightness display are available as optional equipment. Most of the components are designed for worldwide use within ex zones of category II 2G and II 2D, and can be used within extended temperature ranges from -20° C and +50° C. Adequate solutions for use within IECEx Zone 1/21, Class 1 Division 2, GHOST and NEPSI are also planned.

Even the cabinet design includes a number of innovative solutions. Normally, access to the inside of a system for repair and service work requires opening the rear of the cabinet. However, especially with hygiene-critical applications, this has proved to be very impractical. For this reason the feature front access offers optimized access for easy installation and maintenance. This makes them an ideal choice for applications under clean room conditions such as in the pharmaceutical industry. The cabinets not only offer IP66 protection, but are also provided with type 1.4301 (304) or, optionally, type 1.4404 (316L) high-grade steel casings.

Successful right from the start

The new system was presented at Achema 2006 to selected customers. "It was a great success," reported Sittel. "The idea of being able to access all kinds of company applications with comparatively little expense and digital standard Ethernet transmission sounded very appealing to many customers." Some major companies in the chemical industry responded quickly with a decision to fund the installation. As a result, the first projects were underway during the late fall in 2006. Since the necessary prerequisites for this network-based transfer is anchored in the Microsoft operating system, even the large process control system manufacturers envisage no difficulty. "Right now, many users are only at the beginning of a re-thinking process," Sittel concludes, adding: "I am convinced that within four years, some 70 per cent of all HMI solutions in the ex zone will be realized using the VisuNet concept."