Basic Overview of Foxboro IA series DCS system:

Stations are the key active component which will communicate with each other to perform the assigned activities. Many stations associated to a particular process plant or train 1 is linked by Bus call Node bus, they configured in the system definition and dynamically connected. The system will monitor the availability for the stations and its peripherals or related components with periodic bus test. Two fault redundant node buses A& B are available for all nodes.

In an IA series, a node consists of following group of stations related to particular plant required for safe and reliable distributed control system.

1. Work Station Processor (WP) HMI for Process & Maintenance team.2. Application Processor (AP) which is having the node hardware

configuration & application. Mostly act as host to system monitor and back up all stations configure in it in case of reboot or failure.

3. Control process (CP xx) which is the main IA controller performing the process logic & memory program as configured for the customer requirement.

4. Field Bus Module: The module which linked to the field measuring device to the Control Process through the redundant Field bus.

FBM 1, 4 are associated with standard 4-20 ma Input /outputsFBM 7, 40, 41 are with digital input & outputs.Foxboro provides wide range of FBM to meet the various types of process variables.

5. Communication Processor (COMMP) which is used to connect the Printers, Modems and VT 100 terminal for report, alarm and diagnostic.

6. Gateway / Integrator ( GW and DI) : The interface module to read and write data to the other system like PLC, Metering, Tank gauging system etc.,

7. Personnel Workstation (PW) Cheap HMI work station will limit features earlier to WP.

MID- Module Identification Device (Letter Bug) is a essential device for every Foxboro module and Station since entire software configuration recognize the device by their assigned verification through this MAC address technology.

The above components are essential for a single plant or unit Control. In a Process plant with many unit, more nodes in a plant are segregated and designed well for safe integrity and high system reliability. The Node data from one section to other section can inter linked by LAN called Carrier Band LAN (CBLAN). With a CBLAN, all the Nodes in a complex all inter linked and configured for dynamic data exchange and control. CBLAN speed is 5 MBS (Mega bits/sec). CBLAN communication always limited to 5 MBS.

Types of Buses used for Data transfer:

Node BUS, Field Bus and Cell bus

Field Bus is used for FBMS to measure the direct process input /outputs. At a speed of 268.7 kHz/sec in the 100 series legacy version with Z- modules.At a speed of 2 MBS (mega bits /sec) in case of the 200 series FBM with Y

adaptors & with CP60.

Node bus is used for stations communication with in a node. Bus A & B are always redundant and once enabled, A& B will shift every 15 minutes so that Bus integrity is always active and reliable. Speed with 10 MBS (megabits/sec) between CP to cp or cp to AP, WP or AW, DI, CMP in case of legacy model station like CP10, 20, 30, WP, AP, GW30, CMP10 etc. Latest developments: Node bus speed increased from 10 mbs to 100 mbs with high speed Ethernet switch directly configured to the Node Bus via a NCNI module. FBM to FCM at 2MBS, FCM to CP60 at 10mbs. Node extended at 100 mbs via a fiber optic and fast Ethernet switch elimination the CB LAN.

Cell buses are power bus for the each rack modules.

Limitation:

CP30 can have maximum of 64 FBM.CP60 can have 120 FBM.One Node can have maximum of 64 Stations.CBLAN can have maximum of 100 Nodes.Carrier Band LAN Interface is connected by Copper and Fiber.Copper for with in the same Marshalling room and Fiber for long distance.

Fiber Link advantage: SPEED, Distance and Electromagnetic disturbance free.

Communication Protocol:

Foxboro uses IEEE 802.3 spec for communication at layer 2. Layer 2 links two devices by network interface card using Media Access Control (MAC) address for every single device associated to it.

Node Bus using the HUB philosophy with 64 stations with Layer -2 CSMA/CD & IEEE 8023.3 protocol.

Platform used :

1. Unix – Sun micro Solaris for legacy models are known for his stability.2. Windows – NT/XP Microsoft based for market competition.

CP types and its properties :

1. CP30 – 100 series for Legacy FBMs. Can handle 800 blocks with 386 processor.2. CP40 – 100 series for Legacy FBMs. Can handle 800 blocks with 486 processor.3. CP60 – 200 series Din rail mounted new FBMS can handle 4000 blocks with a

Pentium processor. I/O is twice as CP30.

CP30 & CP40 can communicate with 100 series Z-modules (legacy)CP60 is designed mainly for 200 series, but it is compatible with 100 series interface and hardware for smooth upgrade.

Typical Station configurations: CP30 Field Bus :

Typical CP 60 FBM Connection:

FBM01 FBM64

CP30

A-Bus

B-Bus

TX

268.75 Khz

XV Field I/Os

010701

010764

01CP07

MID / Letter bug

Typical Node Bus with Stations:

Software & Hardware inter-links:

FCM01 FCM16

CP60

A-Bus

B-Bus

10 mbs

200 series FBMs - Max 120

2 mbs FBM bus

01CP07

010701

010711

01AP0 01AW01 01WP01

AP AW WP

CP30 CP60 COMP

01CP01 01CP02 M1CM01

GW

01MG01

FBM01 FBM64

A-Bus

B-Bus010701

010764

A node design is critical for the data follow and its station recognition. To protect their Hardware and Software, Foxboro first design the node and prepare a system definition by defining the associated the stations like WP, AP, AW, PW, CMP, CP, GW required for the particular plant or section so that required process condition and operator interface. For higher reliability, critical stations like CP, GW are configures as redundant or fault tolerant so the single bus or single module failure do not affect the system control or plant operation.

Once the system definition is done, the committal software creates a Proprietary committal diskette and need to be installed in all station in order form the above node.

Once the node is established, all the stations can exchange data and customized other graphic and hardware configuration, dynamic values can be configured by the system Engineers.

A committed station will have a System Manager Display Handler (SMDH) which will display all the node or multi-node details.

Station Manger – SMDH is vital for the Foxboro and customer software engineer for regular system monitoring, diagnostics, investigation and for enabling or disabling station for maintenance.

Station ID in White color indicates both the module is healthy & online.Station ID in Yellow color indicates one module or one sub-device/ bus is faulty.Station ID in Red color indicates both modules are not on-line or defective.

CBLAN overview:

Once an active node mainly located in the local control room is ready, it can connected to the another node at the other location or to the centralized Main control room through a CB LAN interface module called CB LAN module so that a multi-node access is achieved for Distributed control strategy.

If the distance between the local control rooms and Main control rooms are longer, Fiber optic link are established between the CB LAN and Fiber optic converter so that a standard 5 mbs CBLAN can be successfully established irrespective for the node distances.

Redundant Module and CB LAN advantage:

1. Since the modules are redundant with dual bus, one bus failure or one module failure due to hardware or software will not affect the plant process operation.

2. If the CB LAN interface module or fiber/copper link fails, only the other node or main control room data transfer will be affect but the CP logic & memory programs will be running normally ensuring continuous control system availability.

Qatargas Node and Hardware types:

QG Foxboro system with 19 nodes was installed during 1995 by Chiyoda and Toyo.

13 Local nodes are at ITR 1 to ITR10, IR, ST and CL.06 MCR nodes for Centralized control.

Before upgrade , Being 90’s design, details of original station details are.

WP – 51 A series Unix stations with to AKP and touch screen.AP- 51 A to host the individual station located at MCR depending on the CB LAN and fiber optic cable for host backup in case of CP failure or reboot.CP – CP 30 legacy Z- modules with 100 series FBM mainly 1, 4, 7, 40, 41.GW – GW30 Modbus integrator for ABB August Safety System TMR, Modicon

Allen Bradly, Siemens, CCC, Mark V, Entis Tank gauging and custody transfer system in Modbus protocol.

CMM – CP10 Communication Processors for modem, printers and VT100.CB LAN – CB interface module.

Each node Host AP machines are located at the related node at MCR with AP 51A station. It has the historian, OAJ and reports configured for that node along with Interfacing for the PI – Plant Operation Database Information for the process parameters.

In case of the CB LAN failure or Fiber optic link failure AP is not available. More Foxboro declared that by 2002 the 51 series hard wares, CP30, GW30 are obsolete. Resulted in upgrading the stations & CPs.After 2002 upgrade:

As result of the hardware obsolescence and slow speed of the LAN, it was decided to upgrade the Host to the latest Style 51F Solaris station at the Local ITR and other work station to upgrade with XP WP stations with dual screens so that the number WP stations can be reduced to 50% with out losing the HMI monitors. CBLAN is eliminated by extending the Local Panel Node bus to Main control via Fiber optic and 100 mbs Ethernet switch. By this the CBLAN is eliminated and MCR access increased to 100mbs. Due to criticality of the plant and requirement of all CP reboot to recognize the newly configured Host, Upgrade is executed along with each plant annual turn-around. Other WP where upgrade online.

Few Trains CP & GW were upgrade to CP60 and GW30B so that the removed old legacy hardware can support the other train failure. Almost 75% upgrade work is completed. Last phase is planned for 2007.

Once the 51A series are upgraded to XP and CP60, it is planned to go for the ATS-Mesh network so that multi-node is more reliable with latest technology.

Database and Software Monitoring sections:

Control Process CP updates the I/O status; execute the Logic and memory programs required for the process control.

I - Image file: Each CP will have a Image file at its Host AP or AW. In case of CP failure or reboot with new hardware, it restores the image with out affecting the control.

HMI-software : The HMI have Graphic representation of process with static and dynamic parts. Unix based Display Manager for style 51 series and Windows based Foxview software are common. The Dynamic parts of the Graphics are linked with Configured CP Block parameter and update the valve instantly along with the associated logics.

ICC- Configurator: Integrated Control Config Tool based on the Unix are used by System Engineers to define and create the station, compounds, blocks and parameters. I/O are configured with unique format called C: B.P. The compound must be unique for the entire CBLAN stations so that the data from compound are unique and shared by all stations. CIO is used for I/O configuration, Logic and Sequential calculations & execution.

Graphics: Display Builder and Display configurator help to develop in UNIX station for the graphic configurations. Fox draw in ver 7.1 solaris and XP stations are latest development for station and dynamic graphic development.

Environment Control : Environment software assign and restrict the difference users privilege and access level of the various Graphic and block functionality. ( Field over only view mode, Control room to access controllers, AI blocks, CAD page access and limited authority to view the “ICC blocks”. Supervisor will have more privilege like Alarm clear or delete, Maintenance Override access and system alarm acknowledgments. Technicians and Engineers will have higher level to override the block, simulate and trouble shoot the system .

CAD : Current Alarm display is the Vital tool to display process cum system alarm and alert the Panel operator for immediate corrective action with in the controlled limit.

SMDH : System related alarms and alerts, Station status, enable or disable of a station can be done though this software. IT can accessed only at Engineers environment.

Historian : Alarm Historian Package ( Hstma or Aim*) allows the engineers to configure block parameter data archive for standard period like 15 days or 30s for case study, trending and operator action Journal recording.

Report Generation : It is another software package to configure a customized set of process parameter values and calculation like daily product report, shift end report etc.

QG DCS tagging and custom file idenfication :

TR1_01PCS_01: 01TI101, 01PT02, 01TAH01,01FT01…. FOR Train TR1 TT,FT etc.

TR2_02FGS_01 : 8GAAH31120S, 8GAHH31110C For Train TR1 F&G inputs

TR1_01ESD_02:1SDY101,1XY101, 1TT202 for Train TR1 ESD I/O.

TR1_01PSS_01: 1TA101,1PA101 From the PSS gateway 01MG01.

Software: All the customized Graphics and other CAD files are saved in /usr/folders with unique directory and numbers based on the unit and tagging philosophy.

Compound parameter ( C:B.P)

1/usr/TR1L3PCS/u0101, /usr/F&GL3TR1/PT_01/usr/UTLL2PCS/u801

Block configuration basics :

I/P O/P

Maintenance :

SMDH will help the system Engineers to minor the system health with corrective actions.

Three month once check all the system back status, try to do Check points and CP load test and configuration SAVEALL. Once a year or after the MOC implement, full station back up is essential.

Routine health check by monitoring SMDH status, system printer message, and printer maintenance.

Study and execute minor medications.

Associate with field team for minor trouble shooting and system diagnostics.

1LT100 1LC100 1LV100

Bcalco for o/p tracking