Dcs Archi.pptx

DCS Architecture & Solution of CAN DCS/ESD Channels Failure

By: Zeeshan Maqsood

Training Overview:     1)

2) 3) 4) 5) 6)

Joined FFCL as GTE on October 10, 2011 2 months in TTC Rotation on UREA, O&U, NP & finally PH&S Got exposure and hands on training on Yokogawa DCS Bentley Nevada 3500 MMS CCC Anti Surge Controller Siemens PLC (PCS7) GE Mark VI Field Instrumentation

Contents: What is DCS?

Yokogawa DCS Architecture

Solutions

Presentation

Problem of DCS channel failure

DCS architecture at Fatima Complex

What is DCS?

A distributed control system (DCS) refers to a control system in which the controller elements are not central in location (like the brain) but are distributed throughout the system. The entire system of controllers is connected by networks for communication and monitoring.

What is DCS? •

DCS system consists minimum of following components

1.

FCS

2.

Operator Station

3.

Engineering Station

What is a DCS? RACK ROOM

FIELD

CCR

4-20 mA Vnet/IP Transmitter

FCS

4-20 mA Control Valve

Comparison of Distributed Control Systems

1. Medium of transmission

Pneumatic implementation

Analog implementation

Digital Implementation

1. Air Pressure

1. Analog Signal

1. Binary Signal

2. Same as pneumatic

2. Digital Computers

2. Computation devices 2. Bellows, Spring 3. Signal Quality 4. Computation device limitation 5. Pros

3. Slow responding and 3. Interference and interference reliability decreases 4. Computation device over long distance wear out quickly 4. Still limited 5. High margin of safety

3. Far less sensitive to noise 4. Virtually no limit on calculation 5. Complex calculations possible

Typical DCS System Architecture

Yokogawa DCS components: •

Operator Station

1.

Referred as HIS (Human Interface Station)

2.

Used for monitoring and controlling purpose

•

Control Station

1.

Referred to as FCS (Field Control Stations)

2.

Core of the system and are necessary to control the plant 24 hours a day, 365 days a year

Yokogawa DCS components: •

Engineering Station

1.

Referred to as EWS (Engineering Work Station)

2.

Used as supervisory station and for configuration of HIS, FCS

•

Control Bus

1.

Dual Redundant Vnet/IP

2.

As important as FCS for controlling purpose

What is Vnet/IP? Vnet/IP is a new control network which maintains the reliability and real-time capability of Vnet, while adding open performance for links with information systems.

Vnet/IP is Open, Reliable and Real-time. Collaborating with various applications via Open Standard Protocol Open Reliable

Securely transmitting information with failure, load, and environmental factors including noise taken into account

Realtime

Transmitting information within a definite period of time

What is Vnet/IP?

• “Vnet” part represents Vnet compatibility and the “IP” indicates an internet protocol for general purpose communication. • Vnet/IP is a 1-Gbps control network that is functionally compatible with Vnet and based on Ethernet.

Communication Classification •

Control Communication Communications for exchanging control data Real-time, highly reliable and stable protocol UDP/IP based

1.

2. 3.

•

Open Communication Communications with Ethernet-based standard protocols (Rest of Control Communication) Equivalent to Communications via Ethernet

1. 2.

Vnet/IP Station (VI701 Equipped)

a)

•

Equalization, Multi host-based engineering , Sequence table/drawing/SEBOL/SFC status display, Other stations’ trends, Process management server/client, OPC, etc. General-purpose Ethernet-Based Device

b)

•

Exaopc client, Exapilot client, Exaquantum client, , PRM client/server, Subsystem communications, Network printers, etc.

Bus 2

OPC

Exaquantum

Open

Open

HIS Vnet

Open

Yokogawa’s dedicated hardware

HIS Vnet

Open

Vnet

HIS-HIS communication

Open communication

PLC communication

Control communication

Control communication

Bus 1

Vnet FCS

Open APCS

Vnet

Open

Vnet

GSGW Vnet/IP System Design

Open PLC

Bandwidth Bus1

Total Bandwidth: •

•

•

Uses Bus1 under normal condition

Open Communication: • • •

•

1 Gbps

Control Communication: •

Normal

Uses Bus2 Open device comm bandwidth is limited within 300Mbps Vnet/IP stations use 650Mbps

Bus 1 Faliure: • •

Control communication shifts to bus 2 Vnet/IP stations bandwidth decrease to 200Mbps

(Reserved) 500Mbps

1Gbps

•

Bus2 Open Comm. Open Devices 300Mbps

Open Comm. Vnet/IP Stations 650Mbps Control & Diag. 500Mbps Diagnosis 50Mbps Limits to 200Mbps

Bus1 Failure Open Comm. Open Devices 300Mbps Open Comm. Vnet/IP Stations 200Mbps

Control & Diag. 500Mbps

Network & System Configuration Specification

Page.16

Network Switches •Layer 2 Switch A device to connect equipment within the Vnet/IP domain. The layer 2 switch, unlike a HUB, incorporates bridge functions to send data to the destination terminal equipment only; it can, therefore, reduce traffic within its domain.

•Layer 3 Switch A switch is used to connect Vnet/IP domains. The layer 3 switch relays a communications frame to another domain with IP address route control, or routing functions. Select layer 3 switch hardware capable of relaying communications frames at high speeds.

Configuration of Yokogawa DCS

Page.18

FFCL DCS Architecture

•

Click here

Problem •

Digital out (DO) channels of CAN DCS/ESD are damaged due to short circuit

•

These channels are used for start/stop command for motors

•

Instrument is providing wet contact to MCC

•

DO channels used for solenoids are safe due to presence of relay

Current situation at CAN plant

Solution # 1

Solution # 2