Cut costs with remote I/O
Retrofitting a tank farm with remote I/O has paid dividends for a US manufacturer

To make more product and cut costs, polymer additive manufacturer Ferro Corporation in Walton Hills, Ohio/USA decided to modernize its tank farm. The ideal solution proved to be a remote I/O system from Pepperl+Fuchs.

One of the objectives of the modernization project at Ferro Corporation was to avoid future limitations on space or functionality. Another was to make new functions available that were not offered by the previous system. The system previously in operation was based on conventional point-to-point wiring, but the company decided that meeting its new objectives required a solution with remote I/O. Ferro is a worldwide supplier of high-quality additive solutions for the polymer industry. The Walton Hill plant produces many tons of product every day, mostly in liquid form. The tank farm is classified as a hazardous area, so all instruments
must be classified as safe to use in explosive atmospheres. With its intrinsically safe signal loops, the RPI remote I/O system from Pepperl+Fuchs offered Ferro the best solution for the task at hand. It combines the advantages of a fieldbus with conventional process automation wiring in one flexibly-configurable interface system.

Single fieldbus connection in place of single-loop wiring
On the field side, the RPI system
retains Pepperl+Fuchs’ proven sensor and actuator system and its individual connections. In the process control system, however, costly single-loop wiring has been replaced by a single fieldbus connection. Field signals in the Ex area are wired in parallel (the standard practice), and the instrumentation itself is conventional.
The connection to the process control system is through a gateway chosen to suit the fieldbus system used, with capacity for up to 500 measurement signals. Freely-combinable I/O modules with up to four channels each are used, with the Pepperl+Fuchs Power-Rail system for installation on DIN mounting rails. Simply snapping the RPI components onto the mounting rail automatically connects the corresponding power supply and data lines, and this drastically simplifies planning and installation.
The system’s great flexibility makes it easy to adapt to specific processes. The power supply and the external and internal bus can be designed redundantly, thus ensuring a high level of availability for the RPI system.
Even while the project was still in progress, Ferro was able to see the advantage of the RPI system in the modernized tank farm. The conversion to RPI involved significantly lower installation costs than would have been required for conventional point-to-point wiring. Eliminating the marshalling distributor, solving space problems in switch cabinets, the ability to use existing on-site wiring to the field devices and reduced costs for system-side wiring all added up to savings of nearly 40 per cent compared with the cost of a conventional system.
Integration using gateway technology
The RPI system was integrated into the Allen-Bradley control system via ControlNet using gateway technology. Since access to the control unit was also possible through the company’s internal WAN (wide-area network), it was of critical importance for the RPI system to be able to communicate with the existing hardware and software platform. Now maintenance personnel have access to practically all areas of the installation from a control terminal—a feature that was previously unavailable, with the exception of the production level. The RPI system fully meets the goals set by Ferro, and even exceeds them in some areas. The overall goal of saving time and money, while at the same time increasing productivity, was also achieved. The flexibility of the system makes it possible to adjust to a wide range of requirements.
Advantages of the RPI remote I/O system
Advantages of the RPI remote I/O system include:
wiring from the remote I/O to the control panel saves space and money;
central access to all devices, for example from a single maintenance system;
components can be replaced without shutting the system down;
extensive diagnostic options, including channel-specific diagnostic information from individual remote I/O components;
connection to different fieldbus systems through gateway technology; and
operation based on FDT/DTM.
RPI is the ideal solution for system modernization, renovation and expansion. Commissioning, repair and maintenance personnel have central access to detailed device information and thus to the system status.