Rhein Chemie Benefits by Choosing Remote I/O
Unbeatable for fieldbus migration solutions
About Rhein Chemie
“Do not necessarily abandon the tried and tested, but do take full advantage of new opportunities"
Figure 1: Part of the plant with associated RPI switch cabinet
In 1992, the plants were converted from pneumatics to electrical systems, and in 2004, a new Process Control System was installed (Freelance 2000, ABB) with PROFIBUS fieldbus technology. A decision needed to be made regarding the way to connect the field devices to the process control system. There were two options:
- Connection with Remote I/O technology (RIO) while retaining the available equipment and the existing field cabling. Advantages were space and cost-saving installation between RIO and Process Control System, and the possibility of central access to the field devices.
- A new installation connecting (new) PROFIBUS PA field devices directly to PROFIBUS with improvements in topology, bus power supply, interchangeability of the devices, comprehensive diagnosis, etc.
The Rhein Chemie solution
Signal transmission from the RPI takes place via PROFIBUS DP – in a combination of wire and fiber-optic cables with corresponding converters – to the switch room, and from there to the allocated Freelance Controller (Figure 3). The fiber optic cable transmission path between the field and switch room is either in a loop (Figure 2, left) or a star (Figure 2, center) configuration.All switch cabinets have an identical design, which greatly simplifies TÜV approval, maintenance, or copying documentation and software. The cabinets are made at the Pepperl+Fuchs plant in Bühl/Germany.
Figure 2: Plant topology after update and before update
- Unchanged field installation of devices and their point-to-point connections to the Remote I/O
- Continued use of economical 4-20 mA devices
- Continued use of available knowledge and experience in commissioning, maintenance and servicing
- Live exchange of components during operation (hot swapping)
- Economical and space-saving wiring from the Remote I/O to control room
- Central access to all devices, e.g., from a maintenance system
- Subsequent upgrades (comprehensive diagnoses, central operation, introduction of PROFIBUS PA devices)
- Faster and easier maintenance
- Possibility of online extensions
- On-site modifications without downtime
- Availability of plant information
Figure 3: Switch cabinet (left) and associated components in the control room (right)
Description of figure 3 elements
2 - PROFIBUS DP between RPI and DP/fiber optic converter
3 - Output from DP/fiber optic converter to the switching room
4 - Input into fiber optic/DP converter from the switching room
5 - Output from the fiber optic/DP converter to the DCS