Yokogawa’s CENTUM VP is a leading distributed control system (DCS) that is widely used in a variety of industries for process control and monitoring. It offers an integrated production control system that combines a high degree of reliability with outstanding performance. Here’s a general overview of the CENTUM VP DCS system architecture.
Image Courtesy: Yokogawa
Yokogawa’s CENTUM VP R6 innovates the engineering environment of DCS. Specifically, it reduces the time and effort required for system construction and engineering. As a further enhancement, a new I/O system, Network I/O (N-IO), was added to the I/O lineup for CENTUM VP.
Earlier Yokogawa system was F-I/O (Field I/O) based. Its control network which uses very high speed Vnet/IP (One Gigabit per second) guarantees operator screen update times within 1 second. Vnet/IP is complying with IEEE 802.3.
Yokogawa’s Centum VP DCS is Distributed Control Architecture which is not based on Client/Server Architecture. In this architecture the database is distributed in each Field Control Station (FCS) which is entirely redundant with less than 1ms switchover time.
The Main Copy of this distributed database resides in the Master Engineering Station. However, this is only a copy with the main database distributed & residing in the Controller. This architecture offers unique advantages which client server architecture cannot offer.
These are
FCS performs control computation functions for each function block and input/output functions for process and software inputs/outputs
HIS is the HMI of the CENUTM VP system for operation and monitoring of plant.
ENG is a computer used for CENUTM VP system configuration and maintenance
Vnet/IP is a control network for connecting CENTUM VP components with each other
N-IO (Network I/O) is the next-generation Smart Configurable I/O.
Yokogawa corroborates with MTL and Pepperl+Fuchs for Intrinsically Safe I/O in hazardous areas. Universal I/O module and their Isolated Barrier (of MTL’s/ Pepperl+Fuchs) install on N-IO baseplate.
Vnet I/P network provides real-time communication with high reliability which is indispensable for stable plant operations. Vnet/IP is a dual-redundant control network, consisting of Bus 1 and Bus 2. Bus 1 is normally used for control communication to transmit control data; however, when the Bus 1 fails, it automatically switches its communication path and Bus 2 continues the control communication without stopping. Furthermore, Bus 2 is capable of handling open communication, the generic Ethernet communication with Non-Centum component like printers. Failure of bus-1 or bus-2 shall in no way limit the open communication.
The Vnet/IP uses general-purpose communication devices for network connection. All the Vnet I/P components like FCS and HIS in a domain are connected to the 1Gbps Ethernet Layer-2 switch. Multiple domains are connected via Ethernet Layer 3 switch. The Vnet/IP domains can be in hierarchy configuration
As shown in earlier figure that, NIU Networked interface units are connected to Controllers via N-ESB cables and bus coupler modules. One NIU can handle 6 nos of Networked I/O modules (N-I/O). One N-I/O can cater 16 no of configurable channels.
One FCS can handle 32 NIUs and 108 N-I/Os (1728 I/O Channels); Each NIU can handle = 6*16 = 96 I/Os
Redundant I/O modules are A2MMM843 which is HART pass through meaning that we do not need extra HART multiplexer. With A2MMM843 I/O module, I/Os can be configured to 2 wire AI, 4 Wire AI, DI, DO with wetted output and DO with contact output. For that below I/O adaptors can be used along with A2MMM843.
All I/O modules i.e. A2MMM843 are connected to NIU individually (No multi dropping). All NIUs are connected to Bus coupler module via ESB Bus / N-ESB Bus / Optical ESB cables. Bus coupler modules installed on controller unit (node) generally talk to CPU/controller. ESB Bus / N-ESB Bus / Optical ESB are decided based on Local NIUs and Remote NIUs.
Left side of N-I/O can be used for field cabling, meaning that Field signals wires are directly connected to I/O modules without any terminal’s blocks. This will have reduced cabinets, reduced inter panel wiring and overall reduced footprints.
The Model number for reference purpose, shown in below table.
Networked I/O System should be designed carefully keeping following points in mind,
To take advantages of configurable I/Os and keep marshalling cabinet similar to old fashioned, there is an option that we can have field wire termination at separate Terminal board (A2BM4) in Marshalling cabinets and then prefab cable is connected to I/O module (A2MMM843) which is in system cabinets. This design will have increased footprints yet offers maintenance flexibility.
Yokogawa ProSafe RS R4 is IEC/TÜV certified to meet the SIL 3 classification requirements. ProSafe RS is a fail-safe, standalone system that does not rely on any other systems to fulfil its function.
Figure: Prosafe RS Single CPU SIS System
ProSafe-RS system features physical redundant CPU with dual CPUs and Dual Circuits in-built in each card, physical redundant I/O module with dual CPUs and Dual Circuits in-built in each card, redundant power supply and redundant communication hence ProSafe-RS is SIL3 certified by TÜV even in single configuration.
Figure: Prosafe RS Redundant CPU SIS System
ProSafe RS is normally integrated with the Centum VP DCS on the same Vnet/IP control network. The adoption of ProSafe RS eliminates the need for a separate gateway between DCS in terms of CENTUM VP and Safety Instrumented System.
A common Human machine interface serves both the DCS & ESD/F&G functions, Operators can access to safety data by using the same HMI used by CENTUM VP. ProSafe RS happens to be true implementation of “One process, One Network, One Window, One solution” concept.
Yokogawa SIS I/O card do not require any adaptors (that is required in case of DCS)
The Model number for reference purpose, shown in below table.
Default output of DO type signal is Wet type (24V DC, 0.2 A per channel). In case of Dry output external relays can be used. However, relay installation location should be critically reviewed in order to avoid interpanel / intrapanel wiring. Functionality of N-IO based Prosafe RS is similar to Centum VP DCS.
Typical Meetings /workshop during project execution
Following is typically applicable for any project execution with any control system vendor, this list is for example only.
Following is example of DCS and ESD controller Make and models.
Typical Control System Engineering Input, output and requirement matrix:
Note: This list can be updated based on project actual scope and requirement by end user.
The information is provided for general informational and educational purposes only. All views expressed on this information are my own and do not represent the opinions of any entity whatsover with which I have been, am now, or will be affiliated. I encourage you to consult your control system vendor for latest information and technological changes.
Author: Jatin Katrodiya
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View Comments
plz I have more knowledge in yokogawa dcs
Hi, first of all, this is a very nice article! It shows a lot of relevant information to be used for system architecture.
However it would be nice if OT Cybersecurity is mentioned. The location of the firewalls (could be both software or hardware) is essential to a safe and secure architecture.
The subject is too large to be descriptive here and hence mentioning it would be a great step in the right direction.
Good luck and please continue producing articles like this!
Ted Angevaare, TAPS
http://Www.TedAngevaare.nl
TAPS@TedAngevaare.nl
excellent
Hi
It is so excellent
And the codes to design of control system and Instrumentation is needed
How about Honeywell EPKS R522, virtuall version
Do you have docs?
Yoko is a flat architecture. The advantage is there is not server hence centralized failure is avoided. But lets talk about huge projects were lots of third party data like modbus TCP/IP, OPC data to be taken from DCS to other systems. This is were server client with inbuilt gateway.
For a DCS it should support both flat & server architecture and the customer should be able to select it. Also NIO technology is something DeltaV launched in 2010 and Yoko/ABB brought in. This is not Disruptive. See how Honeywell has matured the IO Hive & Control HIVE. They are disruptive like Emerson CHARMS. Makes sense to see as new gen and not a copy cat.
Will each operator station fetch data directly from the controller? Won't it impact the controller loading?