Apply new concepts to improve monitoring of existing plants and detect malfunctions before they occur. When these standards are met, the efficiency and availability of machines and plants increase. In this context, the NOA concept provides a side channel for chemical and pharmaceutical industry applications that is used to acquire additional data from the application to improve maintenance and achieve more cost-efficient operation. Side channels also enable new technologies that do not have a negative effect on ongoing plant operation to be used. Further, important plant components can be continuously checked with the help of modern solutions such as cloud connection. To ensure greater user benefits, special requirements such as industrial compatibility, robustness, and reliability must also be implemented. Comprehensive data security is also a significant factor in both existing and new plants. If these general conditions do not exist, users will not be able to install the technology in their plants.
Acquiring additional data
The NOA concept was introduced at the Namur general meeting in November 2016. As mentioned above, a side channel was created to enable access to all key data of the device and provide infrastructure that satisfies the wish of operators to gain a deeper insight and a higher degree of plant openness. What makes this solution special is that it is impact-free and critical processes can continue to run without interruption. Since then new approaches and (further) developments have been presented in November every year. They practically demonstrate how manufacturers and service providers in the industry have understood the requirements of operators and implemented them as products and solutions.
With the NOA concept, additional data can be acquired from field devices, the majority of which currently support the proven 4…20 mA current loop and some of them also have a Hart interface. The information can be immediately used as part of the maintenance and monitoring strategy. When it comes to monitoring and operation, in addition to important 4…20 mA measuring signals, other types of data can be read via Hart communication as a superimposed signal from field devices – irrespective of whether they are sensors or actuators. Typically, Hart functions are only used for replacing devices in the field or workbench calibration – comparable to measuring pulse and blood pressure, which is only done during a visit to the doctor. But today there are smartwatches that continuously log this type of information and can graphically present it for an entire day. This capability is also desirable in industrial applications.
Using special Hart I/O cards that can be integrated into process control engineering (PCE) or the distributed control system (DCS) for the purpose of using the Hart data generates additional costs. Since the data are only of interest to maintenance personnel for device monitoring, Phoenix Contact has developed two solutions for Hart transmission that are used in the framework of a side channel. Both products can be integrated into existing and new process plants, and are continuously further developed to meet the requirements of users and official bodies.
The first approach is the modular Ethernet Hart multiplexer GW PL… bus. It provides the option of configuring and monitoring Hart devices via Ethernet. Hart devices can be integrated into almost any host system via industrial Ethernet systems such as Profinet, Modbus TCP, Hart IP, Emerson AMS, and OPC UA. The analogue control system remains fully operational and does not even need to be shut down for installation. An Ethernet Hart multiplexer consists of a head station and up to five four- or eight-channel Hart extension modules, so that a maximum of 40 Hart devices can be connected to the head station and supplied with current from it. The modular design provides a scalable solution for modern distributed control systems and phased roll-outs. For four years, the Ethernet Hart multiplexer has been proving itself worldwide in smaller applications. It is ideal for installation involving intrinsically safe applications and in combination with additional signal isolators on the Hart devices for Ex zone 2 applications.
Adapted to harsh environments
The second solution that was introduced at the Namur general meeting in November 2019 is an extension to the proven Axioline F I/O system with IP 20 degree of protection. Axioline F features rapid signal acquisition. The robust mechanical system can withstand the harshest ambient conditions due to its excellent shock and vibration resistance. In addition, the extended temperature range from -40 to 70 °C also contributes to an increase in system availability. And installation time is reduced, thanks to fast wiring without tools and easy handling. The I/O system has been extended to include analogue and digital input and output modules for Ex i applications. Now Axioline F can be used in both hybrid and continuous applications. It makes sense to install it where intrinsic safety is required but hot-swap capability is not necessary.
The I/O modules can be coupled with the industrial controllers and bus couplers in the Axioline product family. Users benefit from a solution that is less expensive than PCE/DCS, although the latter satisfies more rigorous requirements and offers PID control capability. However, Axioline F provides a reliable platform for maintaining process field devices that can flexibly adapt to specific general conditions and is subject to ongoing further development. Alongside the standard I/O modules for Hart communication, the intrinsically safe variants open up new opportunities for use in the field. Hart-compatible flow meters deliver additional selectable data, including device runtime, total flow rate, pressure and temperature. As a result, users can implement needs-based maintenance measures and optimise the relevant process. Since the cost of the sensors installed in the process environment have become lower, Namur sensors can be monitored directly through the side channel as discrete signals.
Phoenix Contact GmbH & Co. KG, Blomberg