fieldbus actuators[1]

1

Foundation Fieldbus Actuators

Publication number S114E Date of issue 03/00

PARK

TERM

C23

C43

U27

SK2

LK1

LK2

LK3

LK4

LK5

LK6

LK7

LK8

U26

LK9

C27

C44

C42

C24

2

Foundation Fieldbus SystemsFoundation Fieldbus Systems

Foundation Fieldbus compatible electric and fluid power actuators from Rotork comply with the IEC 61158-2 international standards and ISA–SP50 recommendations for fieldbus devices. The Rotork IQ, IQM, AQ and Q range of electric actuator products and the Flowpak control unit for hydraulic and pneumatic actuators may be controlled over an IEC 61158-2, 2 wire highway using the Foundation Fieldbus system when they are fitted with the FF-01 option module.

Foundation fieldbusFoundation fieldbus

• International open fieldbus standard IEC 61158

• IEC 61158-2, 2 wire communication

• H1 communication bus – speed of 31.25 kbits/sec

• 32 devices per section, extendable to 152 per highway by using repeaters or active couplers.

• Addresses in the range 1 to 240 are accepted.

• Up to 4 repeaters or active couplers per highway

• 1900 metres per section, extendable to 9500 metres per highway by using repeaters or active couplers

• Independently Certified for inter-operability Rotork FFRotork FF--01 Module 01 Module

• Compatible with IQ, IQM, AQ and Q range electric actuators

• Compatible with Flowpak controlled hydraulic and pneumatic actuators

• Greater control system flexibility

• Link Master capability

• 14 Function Blocks

3

Foundation Fieldbus is a digital, serial, two way communication system which interconnects field equipment such as Rotork valve actuators with other sensors or controllers. It differs from any other communication protocol because it is designed to resolve process control applications instead of simply to transfer data in a digital mode. The process control function may be distributed across the network and shared by the elements of the network instead of being performed by a host system, so with Foundation Fieldbus there is no need for a conventional DCS or PLC host system. The system complies with IEC 61158-2, the International Fieldbus standard for use in industrial control systems and follows the Open Systems Interconnect (OSI) 7 layer communication model using layers 1, 2 and 7 (Foundation is like most systems and does not use layers 3 to 6). It is also based on the ISA-SP50 recommendations for fieldbus networks and is designed to utilise standard instrumentation field cables. The field data highway or field network is known as the H1 bus, it operates at a fixed data rate of 31.25 kbits/sec and should be wired in a ‘Type A’ cable. Type A cable is similar to the traditional single twisted pair with overall screen used for conventional field transmitters. The field network can be intrinsically safe with the field cabling and equipment protected by barriers. The drawback of using an IS system is that the number of devices permitted for connection in the hazardous area is reduced to 6. The H1 bus can also be used to power the devices in many cases, just as a traditional 4-20 mA transmitter may be powered by the loop standing current.

The topology or system layout can use simple parallel connected devices directly on the bus highway, or a mixture of tree or spur type branching connections and bus connections. The distances covered by the network varies depending on the connection topology, the type of bus (IS or non-IS), the power drawn from the bus and the network cable’s parameters. Foundation Fieldbus equipped Rotork actuators are explosion-proof and do not require an Intrinsically Safe network. The explosion-proof cables should be contained within an armoured sheath or conduit to preserve the hazardous area protection.

Understanding Foundation FieldbusUnderstanding Foundation Fieldbus

Data Rate 31.25 kbit/s Type Voltage Topology Bus/Tree Total Cable length 1900 m (max) Total Spur length 120 m (max)

Cable Lengths: Type A Cable (e.g. Belden 3076F) Type 2 cores, twisted pair plus

overall screen Shielding Minimum 90% copper

shielding braid or foil Size 18 AWG (0.8 mm2) Resistance 24 ohm/km max Nominal Capacitance

80 pF/m

Control Room

JunctionBox

Trunk

SpurTotal Cable length = Trunk length + all the spur lengths

4


The Rotork FF-01 interface is bus powered and will operate when there is no power on the actuator. The fieldbus interface card draws its power from the bus power supply, consuming a nominal 18 mA. The minimum voltage at which the interface will work correctly is 9 V DC and this must be remembered when considering the layout of the network. IEC 61158-2 specifies that the bus should have a suitable DC power supply connected to it to bias the bus and power the individual Foundation devices. This power supply requires suitable conditioning components to be included or to be connected through a conditioner. Suitable power supplies and conditioners can be obtained from various vendors and are listed on the Foundation web site.

The number of actuators on one segment will depend on their position relative to the power supply, since each will draw current, and the voltage drop along the cables has to be considered. If all the actuators were 1900 metres from the power supply the maximum number permitted would be 12, if they are spaced along the cable the maximum number will be 32. Provided the power supply can deliver the required current and voltage various combinations can be achieved. For example with a 33 V DC power supply capable of delivering 640 mA a network bus of 32 actuators could be made where the devices are spaced every 47 metres along a bus 1500 metres long. Termination conditioning networks must be added at both ends of the main bus. These are complex devices including inductors as well as resistors since they must impedance match the data line at the 31.25 kbits/sec frequency.

The communication between the actuators on the network has to obey the Foundation Fieldbus rules. The rules are based on the OSI model using layers 1, 2 and 7. The Physical layer (layer 1) is the electrical circuit for connection to the cable. The Data Link Layer (layer 2) controls the transmission of messages onto the fieldbus through a deterministic centralised bus scheduler called the Link Active Scheduler (LAS). The Fieldbus Access Sub-layer (which forms part of layer 7), and the Fieldbus Message Specification (the rest of layer 7) handles the connection to the actuator device itself, the access to the function blocks and the definition of the Virtual Field Device (VFD) together with the logical connections to the Data Link Layer (DLL).

Each Foundation device connected on the bus will either be a Basic Device or a Link Master. These two types are capable of different network functions in organising the data movement along the bus. Every bus must have at least one Link Master and all Rotork FF-01 modules have Link Master

PowerSupply

33 Volts

20 volts

JB

12 volts

12 volts

current

conditioner andtermination

PHY

DLL

FAS

FMS

Fieldbus

Actuator

Foundation Fieldbus OSI Model

7 Application Layer

2 Data Link Layer

1 Physical Layer

Maximum voltage 35 V DC

Nominal voltage 32 V DC

Minimum voltage 9 V DC

Current Drain (nominal) 17 mA

Current Drain (maximum) 20 mA

Rotork FF-01 Interface Electrical Parameters

5

capability. One of the actuators will become the Link Active Scheduler (LAS) which effectively maintains the control strategy and organises the routine data passing on the network once the system is configured and running. Any Rotork actuator can become the LAS for the network, if required, without need for intervention by the system operator. The LAS maintains a Live List which is a list of all the connected devices. The list automatically gets updated when actuators are connected to, or removed from, the bus. The LAS uses a Probe Node (PN) message to maintain the list and at least one PN message is sent out for every complete cycle of passing the token to all units in the live list. In addition the LAS controls the CD schedule which is a time based set of activities where the individual function blocks used in the control strategy are allocated a time slot to publish their data – a Compel Data message from the LAS makes the publisher issue the data. All the actuators are publishers though they can use either the CD or the token to issue their information to the bus. The Time Distribution (TD) message issued by the LAS is used to make sure all the devices keep in step. All of the data transmission on the network is controlled by this time. Finally the LAS moves a token around the actuators one at a time with the PT message. It is only when an actuator has the token that it can provide data from its transducer block.

Most messages are issued on a publisher/subscriber basis. This technique makes peer to peer communication very efficient and is also flexible enough for use on master/slave types of system. When the time is right each actuator in turn broadcasts, or publishes, information onto the bus, all other actuators and any host system receive the data and can either discard it or, if they are a subscriber, use it. If the system is a simple master/slave with a host and several actuators, then as each actuator publishes its data the host will subscribe to that data and use it in its display function. When the host has the token it can publish commands aimed at moving the actuators and those that subscribe to the various parts of the message will act on the commands to move. The system is deterministic and so a definitive response can be worked out for the time to collect or issue data provided the number of devices and the method of system configuration are known. The FF-01 has defined time requirements for its function blocks and transducer block. The Fieldbus Access Sublayer (FAS) sets up the communication links between the selected function blocks, data from the transducer block and resource block (defined in the Virtual Field Device) and the Data Link Layer for onward connection to the highway. The links are set up using Virtual Communication Relationships (VCR‘s) which are logical settings inside the FF-01 module, there are 3 types of VCR. Client/Server type VCR’s are used when the actuator has the token, these are useful for queued, unscheduled or user initiated events and can only be used if the device is in possession

Publish

Subscribe Publish

SubscribeSubscribe

PN Probe Node

CD Compel Data

TD Time Distribution

PT Pass Token

Link Active Scheduler tasks

Link Master Device

ActiveLink Master

Device

Link Master Device

Link Master Device

LAS

6

of the token. The client will request data from the server, for example the host might send a new setpoint to an actuator. When the token reaches the actuator it will respond to the message about the new setpoint. Report Distribution type VCR’s, again used only when the actuator is in possession of the token, are for the transmission of trending data and alarms to the operator console. Since the actuator is seldom set up to trend data this form of VCR will not be common. Finally there are the Publisher/Subscriber VCR’s used with the Compel Data commands. These are used for most of the communications and link the data from the function blocks and transducer block to the highway. The Fieldbus Message Specification (FMS) layer defines the Virtual Field Devices. In the VFD the function blocks, transducer block and resource block are called Objects. The FF-01 has a defined set of objects in its Object Dictionary and these relate to the objects described in the DD file used by the system

configurator. Information to and from the function blocks is carried out on the Publisher/Subscriber VCR’s when a Compel Data request from the LAS is received.

Every Foundation device includes function blocks, these are the building blocks used for the process control application, or the desired system response to changes on the inputs. These function blocks are logical devices that reside physically in the Rotork FF-01 or other Foundation Fieldbus compatible devices. The Rotork FF-01 interface includes five types of process function blocks plus the two blocks that always exist in every device, the transducer block and the resource block.

• The transducer block is used to logically connect the real hardware (the actuator itself in the Rotork case) to the network and process function blocks.

• The resource block contains information about the actuator itself, like the device name, the manufacturer and the serial number.

• The process function blocks in the FF-01 are DI (digital input), DO (digital output), AI (analogue input), AO (analogue output) and PID (three term controller). Inputs are feedback signals from the actuator to the network and may be valve position or local /remote selector status. Outputs are the commands to open and close the valve.

The network is logically assembled using the Object Dictionary, function blocks, virtual wiring using VCR’s and data transmission methods depending on the command from the Link Active Scheduler (Pass Token, Compel Data etc.). Publisher/Subscriber messages are scheduled in the LAS and when the actuator receives a CD command from the LAS it will broadcast the specified data to the remainder of the network. The VCR is used to define the route used to connect the devices


PHY

DLL

FAS

FMS

Fieldbus

Function Blocks

User Application

VFD

System Management

VFD

Rotork FF-01 Function Blocks Digital Input DI 2 blocks for feedback data Digital Output DO 8 blocks for commands Analogue Input AI 2 blocks feedback data Analogue Output AO

1 block for command

PID 1 block for 3 term controller

Resource block 1 block Transducer block 1 block

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together for these messages and it is used for data exchange between the various function blocks assembled to solve the process control requirement. The setting up of a system requires the use of a suitable configuration tool. Actuator addresses are automatically set by the system. When a new device is detected by the PN message the device adopts a default address. The configuration tool is then used to give the device a tag and the system will then automatically allocate an address. All future references to the actuator or its function blocks will be via their tag names and never make use of an address. Since the actuator must be tagged it is essential to have a configuration tool during commissioning. Function blocks in the FF-01 that are required to execute must be scheduled in the LAS. The configuration tool is used to perform this scheduling and each block must be allowed sufficient time for complete execution as well as

time to transmit its data onto the fieldbus if required. Note that the several blocks can execute at the same time, but only one block can have access to transmit at any time. The cycle time to execute all the blocks should allow sufficient spare capacity to ensure that all unscheduled events can also take place. In the diagram Actuator 2 DO channel 1 is used to operate the actuator, so it does not require any transmission access time on the highway. Actuator 1 needs to pass the state of its DI channel to Actuator 2, so it does require transmission access time. Any execution time not used for highway access is free for routine PT (Pass Token) messages, Transducer block interrogation and general housekeeping on the network and Live List by the LAS. The network commissioning process involves using a configuration tool such as those available from National Instruments or SMAR, the FF-01 Device Description file and other FF-01 files, as well as other DD’s and files needed for other devices on the network. A knowledge of the physical number devices and their distribution on the highway will also be needed. The configuration tool will allow the individual function blocks to be interconnected and the timing schedule to be set up. It is very important to ensure that the timing schedule has sufficient length to execute and transmit the chosen data over the highway. The time needed to do this will vary depending on the data to be moved and the number of devices on the network.

2x DI

8 x DO

2 x AI

1 x AO

PID

Actuator

Transducer

Resource

Data

Hig

hw

ay

FF-01 module

Data

Lin

k L

ayer

Fie

ldb

us A

ccess S

ub

layer

Fie

ldb

us M

essag

e S

pecific

ati

on

Absolute Link Schedule Start Time

Actuator 1 DI channel 1function block

Actuator 2 DO channel 1function block

Execution

Transmission

Execution

Unscheduled Communication Permitted

0 30 60 90 120 150 180 210

Sequence repeats

mS

8

FFFF--01 Function Blocks01 Function Blocks

Rotork FF-01 Function Block Execution and Transmission Times Block Type Execution Time Transmission Time

Digital Input DI 30 mSec 40 mSec Digital Output DO 35 mSec 40 mSec Transducer Not applicable 40 mSec Analogue Input AI 35 mSec 40 mSec Analogue Output AO 30 mSec 40 mSec PID 70 mSec 40 mSec Resource Not applicable

INPUT (AI) A_POS (AO)

CONTROL (PID)

OUT

Trends

Alarms

Cas IN OUT

Alarms

BKCal Out

Trends

OUT

Alarms

BKCal Out

TrendsBKCal In

TRK In D

TRK Val

FF Val

Cas IN

IN

OUTPUT (AO)

Cas IN OUT

Alarms

BKCal Out

Trends

Two function blocks for use in the process control application handle Digital Inputs. The feedback signals used in the blocks are selected from information in the transducer block table. For routine data input to a supervisory system the host reads data directly from the transducer block.

Block No. Function DI 1 1 of 00-38 in table DI 2 1 of 00-38 in table

Digital Input Blocks Digital Input Blocks

Digital Output Blocks Digital Output Blocks

There are eight Digital Output blocks, each of which has a pre-defined function in the control of the actuator. The Interlock command allows the actuator interlock function to be added to the process control strategy. On the IQ blocks DO5 to DO8 control the output relays of the actuator if these are not being used for indication. On Q, AQ and Flowpak DO5 to DO8 are not used.

Block No. Function DO 1 Open Command DO 2 Close Command DO 3 ESD Command DO 4 Interlock Command DO 5 Relay 1 Command (IQ) DO 6 Relay 2 Command (IQ) DO 7 Relay 3 Command (IQ) DO 8 Relay 4 Command (IQ)

2x DI

8 x DO

1 x AO

Actuator

Transducer

Data Highway

2 x AI

2x DI

8 x DO

1 x AO

Actuator

Transducer

Data Highway

2 x AI

9

The Transducer block defines the connections to and from the actuator itself and the function blocks, as well as to the Foundation highway. The DI/DO/AI/AO function blocks connect to the transducer block to access information or control the actuator. All the data in the Transducer Events table can be read by a host from the Transducer block directly. The data labels for the information are described to the host system by the Device Description file. The Transducer block also holds information on the settings for the control of the actuator by the FF-01 module. All the data in the transducer block is automatically transmitted to the highway each time the actuator gets the Pass Token.

Transducer Block Transducer Block

2x DI

8 x DO

1 x AO

Actuator

Transducer

Data Highway

2 x AI

Transducer Events Table

No Identifier Description

00 STOP Stop Command Issued 01 OPEN Open Command issued 02 CLOSE Close Command Issued 03 INHIBITED Motion Inhibit Timer Running 04 LOCAL OVERRIDE Local Selected 05 POSITION ACHIEVED Stationary – Mid Travel 06 TORQUE ACHIEVED Torque Trip 07 MOVING Actuator Moving 08 POSITION & STOP Stopped Mid Travel at Desired Position 09 POSITION & OPEN Valve Open Limit Switch 10 POSITION & CLOSE Valve Closed Limit Switch 11 TORQUE & OPEN Valve Open Torque Switch 12 TORQUE & CLOSE Valve Closed Torque Switch 13 MOVING & OPEN Travelling in Open Direction 14 MOVING & CLOSE Travelling in Close Direction 15 LOCAL OVERRIDE & STOP Local Stop Selected 16 FAIL & MIDPOS @ Torque Valve Obstructed 17 Reserved Reserved 18 Reserved Reserved 19 AUX INPUT 1 Auxiliary Input 1 Active 20 AUX INPUT 2 Auxiliary Input 2 Active 21 AUX INPUT 3 Auxiliary Input 3 Active 22 AUX INPUT 4 Auxiliary Input 4 Active 23 INTERRUPTED TIMER Interrupter Timer Running 24 BLINKER Blinker On 25 INTERLOCK Interlock Active (electrical movement not permitted) 26 Reserved Reserved 27 INTERLOCK & STOP Interlock Active and Stop Command Issued 28 INTERLOCK & CLOSE Interlock Active and Close Command Issued 29 INTERLOCK & OPEN Interlock Active and Open Command Issued 30 INTERLOCK & BOTH Interlock Active and both Open and Close Command Issued 31 Reserved Reserved 32 Reserved Reserved 33 FAIL & ESD ESD Command Issued 34 FAIL & CONTROL NOT AVAILABLE Monitor Relay (Local, Local Stop, or Thermostat tripped) 35 FAIL & LOW BATTERY Low Battery 36 FAIL & STALLED Valve Jammed 37 FAIL & HANDWHEEL Manual Movement Detected 38 FAIL & HOT Thermostat Trip

10

FFFF--01 Function Blocks01 Function Blocks

Analogue Input Blocks Analogue Input Blocks

Two function blocks handle analogue inputs. The two Analogue Inputs are connected via the transducer block to the two analogue measurements on the IQ actuator giving position and torque feedback data. Note: On Q, AQ and Flowpak actuators there is no analogue torque signal and Q and AQ actuators require a potentiometer to be fitted for the valve position AI.

Analogue Output Block Analogue Output Block

One function block is available for positioning the actuator using an analogue output . It connects to the transducer block to send the desired analogue position for the valve to adopt. If a digital signal is sent to the actuator the analogue positioning algorithm is disabled until a new analogue value is sent over the FF highway. Note: On Q, AQ actuators the actuator must be fitted with a potentiometer for valve desired position AO.

2x DI

8 x DO

1 x AO

Actuator

Transducer

Data Highway

2 x AI

2x DI

8 x DO

1 x AO

Actuator

Transducer

Data Highway

2 x AI

Block No. Function AO 1 Valve Desired position

Block No. Function AI 1 Valve position AI 2 Actuator torque (IQ)

The PID block provides full 3 term control executed in 70 mSec. The Reset, Rate and Gain parameters are all set over the network and the function block meets the standards described in FF-891-1.4 The block does not connect internally to the Transducer block and can be used as a stand alone controller linking to AI and AO blocks elsewhere on the highway.

PID Control Block PID Control Block

Resource Block Resource Block

The Resource block includes characteristics of the FF-01 device and the serial number of the module. The device is identified as a Rotork FF-01 and the Configuration tool examines the Resource block to identify the correct DD file to use. The block also contains common data related to all the other function blocks.

2x DI

1 x AO

Data Highway

2 x AI8 x DO PID

2x DI

1 x AO

Data Highway

2 x AI8 x DO

Resource

11

Electrical Interface: IEC 61158-2 electrical standard for 2 wire connection

Data Encoding: Manchester Biphase-L

Data Rate: 31.25 kbits/sec

Processor isolation: Optical

Communications Interface: SMAR

Communication protocol: Foundation Fieldbus IEC-61158-2

Function Blocks: 2xAI; 1xAO; 2xDI; 8xDO; 1xPID; Transducer; Resource

Power consumption: 18 mA nominal, (20 mA max) from the data highway

Interface Operating Voltage: 9V to 32V DC

Data Files: Device Description (DD) file 0101.FFO Capability file 0101.CFF Symbol file 0101.SYM All available on disk

Enclosure: Suitable for fitting to Rotork IQ, AQ and Q electric actuators and Flowpak controlled fluid power actuators

Environment: As the actuator (-40 to +70 C)

The Rotork FF-01 Network Interface module has been approved by the Foundation for conformance with the IEC 61158-2 specifications and inter-operability with other similar devices. The FF-01 is a Foundation registered device as defined by FF-542. For more information on Foundation Fieldbus consult your regional User Group.

The Foundation web site at http://www.foundation.org provides answers to many common questions. In addition Foundation system documentation is available from the resources section of the Foundation web site. Further information on all Rotork actuator products can be found on the Rotork web site at http://www.rotork.com

Technical DataTechnical DataTechnical Data

Device Description File Device Description File

The Device Description file (DD file) provides an extended description of all the items in the FF-01 module’s Virtual Field Device. That is the function blocks, resource and transducer blocks. The text label identifies each signal and data bit so that the configuration tool can easily be used to interconnect the function blocks to make up the control system required. The DD file is like a ’driver’ for the FF-01 and the rotork DD file is written using the Common File Format to FF-940-1.4.

Technical DetailsTechnical Details

12

telephone telefax e-mail

AUSTRALIA Ballarat (0353) 381566 (0353) 381570 [email protected]

CANADA Calgary (403) 569 9455 (403) 569 9414 [email protected]

CANADA Toronto (905) 602 5665 (905) 602 5669 [email protected]

CHINA Shanghai (021) 62787680 (021) 62787681 [email protected]

CHINA (North and Central) Beijing (10) 64621617 (10) 64620713 [email protected]

FRANCE Paris (01) 43 11 15 50 (01) 48 35 42 54 [email protected]

GERMANY Hilden (02103) 54098 (02103) 54090 [email protected]

HONG KONG & S. CHINA 2 520 2390 2 528 9746 [email protected]

INDIA Chennai (044) 6254219 (044) 6257108 [email protected]

INDONESIA Jakarta (21) 5806764 (21) 5812757 [email protected]

ITALY Milan (02) 45703300 (02) 45703301 [email protected]

JAPAN Tokyo (03) 3294 8551 (03) 3294 6460 [email protected]

KOREA (SOUTH) Seoul (02) 565 4803 (02) 565 4802 [email protected]

MALAYSIA Kuala Lumpor (03) 5193093 (03) 5193098 [email protected]

NETHERLANDS Rotterdam (010) 414 6911 (010) 414 4750 [email protected]

RUSSIA Moscow (095) 2292463 (503) 2349125 [email protected]

SAUDI ARABIA Al Khobar (03) 833 0702 (03) 833 9369 [email protected]

Singapore 4571233 4576011 [email protected]

South Africa (11) 453 9741 (11) 453 9894 [email protected]

Spain (94) 676 60 11 (94) 676 60 18 [email protected]

Thailand (02) 272 7165 (02) 272 7167 [email protected]

USA Houston (713) 782 5888 (713) 782 8524 [email protected]

Venezuela & N. Antilles Caracas (02) 285 4208 (02) 285 8050 [email protected]

UK head office Rotork Controls Ltd telephone Bath (01225) 733200 telefax (01225) 333467

USA head office Rotork Controls Inc telephone Rochester (716) 328 1550 telefax (716) 328 5848

As we are continually developing our products, their design is subject to change without notice. The name Rotork is a registered trade mark. Rotork recognises all registered trade marks.

http://www.rotork.com

AI Analogue Input AO Analogue Output CD Compel Data DCS Distributed Control System DD Device Description (file) DI Digital Input DLL Data Link Layer DO Digital Output FAS Fieldbus Access Sublayer FMS Fieldbus Message System H1 Standard 31.25 kbit/s fieldbus HSE High Speed Ethernet bus IEC International Electrotechnical Committee

IS Intrinsically Safe ISA Instrument Society of America LAS Link Active Scheduler OSI Open Systems Interconnect PHY Physical Layer PID Proportional, Integral and Derivative PLC Programmable Logic Controller PN Probe Node PT Pass Token TD Time Distribution VCR Virtual Communication Relationship VFD Virtual Field Device

GlossaryGlossaryGlossary

fieldbus actuators[1]

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