Redundant solutions from the control system to the field device.
As a major Distributed Control System provider ABB has a comprehensive strategy for redundant system components. These features are further enhanced by Profibus fieldbus technology as described here.
The scalable Profibus redundancy concept developed by ABB provides three levels of independent redundancy
(All forms of redundancy can be combined with one another as required)
-Slave level redundancy
-Wiring level redundancy
-Master level redundancy
-Slave level redundancy
For Profibus DP ABB offers two different redundant concepts.
- Salve with two Profibus DP interfaces integrated into the salve. Examples include Remote IO Systems S900 and S800 and the Linking Device LD 800P.
- For DP slave with a single Profibus DP interface then the user can install a Redundancy Link Module RLM01 near the DP salve in the field. The RLM01 provides line (cable redundancy) between the Profibus Master and Slave.
For Profibus PA ABB offer the user the Field Barrier FB 900 to increase the availability with the using of built-in short-circuit-protection of each PA spur from the FB 900.
-Wiring level redundancy
In the case of line redundancy, the Profibus DP bus lines are duplicated transparently to the applicatoin. This means that the functionality is not restricted in any way should one bus line fail. The realization is by way of the ABB Redundancy Link Module RLM01. The Module generates, from one single DP line, two redundant DP lines and vice versa.
-Master level redundancy
For the user, the DP master with its redundant DP interfaces are independent of any line redundancy that may exist. Existing slaves can be used without the need of modification. Furthermore, the user can switch smoothly between the redundant DP lines without loss of process data or having to re-initialize the bus. This prevents slave outputs from dropping out.
Also the Controller can be built up in a redundant structure. The defective Controller can be replaced at any time without risk. A newly inserted module adjusts itself automatically and is available again within a short space of time.
Summary:
ABB offers a solution for fieldbus redundancy that allows various redundancy structures and is completely Profibus-compliant.