Спецификация протокола Profibus
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Page 881
PROFIBUS-Specification-Normative-Parts-8:1997
Copyright by PNO 1997 - all rights reserved
Annex 2-B (normative)
Mixed Operation
2-B.1 Mixed Operation of FMS- and DP-Devices on the same Line
The mixed operation of both device types on the same line is possible. In the
mixed mode, the FMS-devices communicate with each other and the DP-devices
communicate with each other. A communication between application instances of
FMS- and DP-devices on the same line is not possible. For both device types, the
medium access is realized according to the the Data Link Layer Service Protocol
Specifications.
During the configuration of a mixed system, the choice of the layer 2 bus
parameters shall be considered carefully. The following conditions are valid:
- Each master shall be able to accept a Ready-Time T
RDY
≤ 250 t
Bit
.
- After power-on, FMS-devices shall operate with the default-values
which are specified for the FMS-Operation-Mode.
- After power-on, DP-devices shall operate with the bus parameters
which are specified in table 2-B.1. In this operation mode no
special precautions are necessary in the DP-Slave.
- The configuration of the DP-Slaves and FMS-devices shall be
harmonized one after another (station address, bus parameter,
etc.).
- FMS-devices shall not use the SAPs 54 to 62 and NIL.
Table 2-B.1. Default-Bus Parameters for DP-devices in mixed operation with FMS-
devices which only support baud rates up to 500kBit/s.
+-----------------+-------+-------+-------+-------+-------+
!Baud rate in ! 9.6 ! 19.2 ! 93.75 ! 187.5 ! 500 !
!kbit/s ! ! ! ! ! !
+-----------------+-------+-------+-------+-------+-------+
!Default-DP-Master! ! ! ! ! !
!T
SL
(t
Bit
) ! 125 ! 250 ! 600 ! 1500 ! 3500 !
!min T
SDR
(t
Bit
) ! 30 ! 60 ! 125 ! 250 ! 500 !
!max T
SDR
(t
Bit
) ! 60 ! 120 ! 250 ! 500 ! 1000 !
!T
SET
(t
Bit
) ! 1 ! 1 ! 1 ! 1 ! 1 !
!T
QUI
(t
Bit
) ! 0 ! 0 ! 0 ! 0 ! 0 !
!G ! 1 ! 1 ! 1 ! 1 ! 1 !
!HSA ! 126 ! 126 ! 126 ! 126 ! 126 !
!max_retry_limit ! 1 ! 1 ! 1 ! 1 ! 1 !
! ! ! ! ! ! !
!Default-DP-Slave ! ! ! ! ! !
!min T
SDR
(t
Bit
) ! 11 ! 11 ! 11 ! 11 ! 11 !
+-----------------+-------+-------+-------+-------+-------+
An optimization of the bus parameters may enhance the data transfer rate. In
this case, the optimized bus parameters shall be loaded into the FMS- and into
the DP-devices.
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Copyright by PNO 1997 - all rights reserved
2-B.2 Mixed Operation of DP and FMS in the same Device
2-B.2.1 General
For special applications it may be necessary to realize devices that contain
both PROFIBUS layer 7 protocol (FMS) and the PROFIBUS-DP protocol in a single
implementation. This possibility exists because both PROFIBUS variations
uniquely use the FDL and FMA1/2-services for the medium access protocol.
The principle protocol architecture is shown in figure 2-B.1.
+--------------------------------------------------------------+
! !
! A p p l i c a t i o n P r o c e s s !
! !
+--------------------------------------------------------------+
^ ^
! !
! DP-Functions ! FMS-Services
! and Data Interface !
! !
V V
+-----------------------------+--------------------------------+
! D P ! !
! according to Part 8 ! e m p t y !
! U s e r - I n t e r f a c e ! !
+-----------------------------+ !
! D D L M ! !
! ! !
+-----------------------------+-------------------+------------+
! ! F M S ! !
! ! according to ! F M A 7 !
! ! Part 5 ! according !
! e m p t y +-------------------+ to !
! ! L L I ! Part 7 !
! ! according to ! !
! ! Part 6 ! !
+-----------------------------+-------------------+------------+
^ ^ ^
! FDL and FMA 1/2 ! FDL and FMA 1/2 !FMA 1/2
! Services ! Services !Services
v v v
+--------------------------------------------------------------+
! SAP SAP !
! 54 until 62 and NIL 0 until 53 and 63 !
! !
! F D L and F M A 1/2 !
! according to Part 2 to Part 4 !
! !
+--------------------------------------------------------------+
Figure 2-B.1. Architecture of composite PROFIBUS Implementations
In this protocol architecture the FDL takes care of the distinction between a
PROFIBUS-DP function or a FMS-service. This distinction is based on the used
service access points. Both protocols use the FDL service access points as a
sub-addressing mechanism.
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Copyright by PNO 1997 - all rights reserved
In the case of PROFIBUS-DP, fixed functions are assigned to the service access
points. By addressing a certain service access point, a fixed function is called
implicitly.
In the case of PROFIBUS-FMS, the service access points are used for the
assignment of the layer 2 L_sdu´s to the logical connections.
Composite devices are able to communicate on application level with other FMS-
devices using FMS-functions and to communicate with other DP-devices using DP-
functions. Composite devices are able to communicate in any way with other FMS-
or DP-devices on the same line.
During the configuration and operation of these devices, the choice of the
layer 2 bus parameters shall be handled with special observance.
In a DP-system, a composite device starts with DP-default bus parameters. In a
mixed system, it starts with the default values defined in table 2-B.2.
For a composite device the station address shall not be changed over the bus
(Set_Slave_Add). In case of changing the bus parameters during the operation
mode (FMA7 functions or Set_Bus_Par) it shall be ensured that the bus parameters
are changed in both protocol-instances.
In a composite device a local management is necessary for the co-ordination of
the parallel execution of the FMA1/2-services. This management is not taken into
consideration in this specification.
At start-up or reset of a composite device, the FMA7 co-ordinates the reset
functions of both protocol-instances.
2-B.2.2 Configuration Instructions for Composite Devices
If in the same device PROFIBUS-FMS-services and PROFIBUS-DP-functions are
simultaneously executed, the following configuration-instructions shall be
noticed:
At the FMS-Slave / DP-Slave:
- The service access points 55 until 62 and NIL are reserved for the DP-
protocol.
- All other service access points (0 until 54 and 63) are usable for the
FMS-protocol without restrictions.
At the FMS-master / DP-Master:
- The service access points 54, 62 and NIL are reserved for the DP-protocol.
- All other service access points are usable without restrictions for the
FMS-protocol.
In both cases, the instructions of section "Bus Parameter" shall be noticed for
the choice of the layer 2 bus parameters.
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PROFIBUS-Specification-Normative-Parts-8:1997
Copyright by PNO 1997 - all rights reserved
Table 2-B.2. Default Bus Parameter for slave composite device in mixed operation
with FMS- and DP-devices.
+-----------------+-------+-------+-------+-------+-------+-------+
!Baud rate in ! 9.6 ! 19.2 ! 93.75 ! 187.5 ! 500 ! 1500 !
!kbit/s ! ! ! ! ! ! !
+-----------------+-------+-------+-------+-------+-------+-------+
! ! ! ! ! ! ! !
!min T
SDR
(t
Bit
) ! 30 ! 60 ! 125 ! 250 ! 255 ! 255 !
! ! ! ! ! ! ! !
+-----------------+-------+-------+-------+-------+-------+-------+
For the calculation of the system reaction time in the mixed mode, the device
specific features for the execution of layer 2 shall be noticed. All DP-Master -
DP-Slave functions are executed with high priority.
Therefore there are two alternatives to prioritize DP- and FMS-services:
a) DP-functions should be preferred against FMS-services.
- FMS-services should executed with low priority.
- The choice of the Target Rotation Time should be made that way that at each
token receipt a complete slave poll cycle can be executed, see section
"Token Rotation Time".
- At each token receipt only one FMS-Service should be executed.
b) DP- and FMS-services shall have the same priority.
- The choice of the Target Rotation Time should be made that way that at each
token receipt a complete slave poll cycle and in addition several FMS-
services should be executed.
- The Target Rotation Time shall have the same value in all masters.
Page 885
PROFIBUS-Specification-Normative-Parts-9:1997
Copyright by PNO 1997 - all rights reserved
PROFIBUS Specification - Normative Parts
Part 9
Physical Layer and Data Link Layer for Process Automation
Page 886
PROFIBUS-Specification-Normative-Parts-9:1997
Copyright by PNO 1997 - all rights reserved
Contents
Page
1 Introduction .......................................................888
2 Field of Application ...............................................889
3 Normative References ...............................................889
4 General ............................................................889
4.1 Definitions ........................................................889
4.2 Abbreviations ......................................................889
4.3 Basic Properties ...................................................890
5 Characteristic Features ............................................890
6 Scope ..............................................................891
7 Data Transmission (Physical Medium, Physical Layer) ................891
7.1 Electrical Characteristics .........................................891
7.2 Interface between Physical Layer (PhL) and Medium Access and
Transmission Protocol (FDL) ........................................893
7.3 Redundancy of Physical Layer and Medium (optional) .................894
8 Medium Access Methods and Transmission Protocol (Data Link
Layer, FDL) ........................................................894
8.1 Transmission Procedures and FDL Controller .........................894
8.1.1 Token Procedures ...................................................894
8.1.1.1 Token Passing ......................................................894
8.1.1.2 Addition and Removal of Stations ...................................894
8.1.1.3 (Re)Initialization the Logical Token Ring ..........................894
8.1.1.4 Token Rotation Time ................................................895
8.1.1.5 Message Priorities .................................................895
8.1.2 Acyclic Request or Send / Request Mode .............................895
8.1.3 Cyclic Send / Request Mode .........................................895
8.1.4 Request FDL Status of all Stations (Live List) .....................895
8.1.5 Status of the FDL Controller .......................................895
8.1.6 FDL Initialization .................................................895
8.1.7 Timer Operation ....................................................895
8.2 Cycle and System Reaction Times ....................................899
8.2.1 Token Cycle Time ...................................................899
8.2.2 Message Cycle Time .................................................900
8.2.3 System Reaction Times ..............................................900
8.3 Error Control Procedures ...........................................900
8.4 Timers and Counters ...............................................900
8.5 Frame Structure ....................................................901
8.5.1 Frame Character ....................................................902
8.6 Frame Formats ......................................................902
8.6.1 Frames of fixed Length with no Data Field ..........................903
9.6.2 Frames of fixed Length with Data Field .............................904
8.6.3 Frames with variable Data Field Length .............................904
8.7 Token Frame ........................................................905
8.8 Length, Address, Control and Check Octet ...........................905
8.8.1 Length Octet (LE) ..................................................905
8.8.2 Address Octet (DA/SA) ..............................................905
8.8.2.1 Link Service Access Point (LSAP) ...................................905
8.8.3 Control Octet (FC) .................................................905
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Copyright by PNO 1997 - all rights reserved
8.8.4 Check Octet (FCS).................................................. 905
8.8.5 Data Field (DATA_UNIT)............................................. 907
8.9 Transmission Procedures............................................ 907
9 PROFIBUS Layer 2 Interface......................................... 907
9.1 FDL User - FDL Interface........................................... 907
9.2 FMA1/2 User - FMA1/2 Interface..................................... 907
10 Management (FMA1/2)................................................ 907
10.1 General Description of FMA1/2 Functions............................ 907
10.2 FDL - FMA1/2 Interface............................................. 907
10.2.1 Overview of Services............................................... 907
10.2.2 Overview of Interactions........................................... 908
10.2.3 Detailed Specification of Services and Interactions................ 908
10.2.3.1 Reset FDL.......................................................... 908
10.2.3.2 Set Value FDL, Read Value FDL...................................... 908
10.2.3.3 Fault FDL.......................................................... 908
10.3 PhL - FMA1/2 Interface............................................. 908
10.3.1 Overview of Services............................................... 908
10.3.2 Overview of Interactions........................................... 909
10.3.3 Detailed Specification of Services and Interactions................ 910
10.3.3.1 Reset PhL.......................................................... 910
10.3.3.2 Set Value PhL, Get Value PhL....................................... 910
10.3.3.3 Event PhL.......................................................... 912
10.4 Coding of the FDL and PhL Variables................................ 912
10.4.1 Coding of the FDL-Variables........................................ 912
11.4.2 Coding of the Variables............................................ 912
10.4.3 List of Object Attributes.......................................... 914
Appendix A (informative) .................................................... 915
Examples of Realizations .................................................... 915
A.1 Repeater........................................................... 915
A.2 Structures of PROFIBUS Controllers................................. 915
A.3 System with several Bus Lines to one Control Station............... 915
A.4 Redundant Control Station.......................................... 915
A.5 Bus Analysis / Diagnostic Unit (Bus Monitor)....................... 915
A.6 Intrinsically safe Fieldbus with Power Supply...................... 915
A.7 Message Rate, System Reaction Time and Token Rotation Time......... 916
Page 888
PROFIBUS-Specification-Normative-Parts-9:1997
Copyright by PNO 1997 - all rights reserved
1 Introduction
This part describes, as already announced in the PROFIBUS Specification, Part 2
Data Transmission, a further data transmission technique, consisting of the
transmission medium (Physical Medium) and the accompanying Physical Layer. The
connecting Data Link Layer and the management of the Physical Layer comply to
the PROFIBUS Specification, except for the changes and additions described in
this part.
FMS
(PROFIBUS Spec., Part 5 and 6)
DP
(PROFIBUS Spec., Part 8)
Data-Link-Layer (FDL)
References to PROFIBUS Specification Part 3 and 4
FDL-Phy-Interface
(PROFIBUS Spec., Part 2)
FDL-PhL-Interface
Phy - Layer
RS 485
(PROFIBUS Spec., Part 2)
Phy - Layer
References to IEC 1158-2
FMS : Fieldbus Message Specification
DP : Decentralized Periphery
FDL : Fieldbus Data Link Layer
Figure 1: Relationship of this part to the other parts
The interfaces to the Application Layer (FDL and FMA1/2) are specified as in
PROFIBUS Specification Layer 2 Interface.
The logical interface used between PhL and FDL is as defined in PROFIBUS
Specification "Data Transmission". The protocol for the bus line, access and
transmission complies to PROFIBUS Specification "Medium Access Methods" and
"Transmission Protocol".
The data transmission is defined according to IEC 1158-2 which enables in
addition the intrinsic safe variant in the protection class "Intrinsic Safe" and
power supply over the bus.
Regarding the Medium Attachment Unit (MAU), the following transmission rate
defined in IEC 1158-2, clause 11, is used:
- 31.25 kbit/s, voltage mode and wire medium.
The management assigned to the Application Layer and described in Part 7 shall
take the Physical Layer variables of IEC 1158-2 and their associated ranges of
values into account (see subclause 10.4 of this part).
Applications in process automation (e.g. process industries) require a simple
transmission medium (2 wire cable) in different topologies, such as line and
tree. Furthermore, low power and low cost bus connections with real time
behavior, i.e. with guaranteed response time, are necessary. Severe
electromagnetic interference and explosive atmospheres may have to be dealt
with.
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This specification shall contribute to the low cost interconnection of digital
field devices from different vendors in a distributed fieldbus system as well as
towards ensuring reliable communication.
2 Field of Application
This specification defines functional, electrical and mechanical features of a
serial fieldbus system for applications in process automation (e.g. process
industries). The data transmission defined in this specification is the Physical
Layer ’version 1’ (31.25 kbit/s, voltage mode, wire medium) of IEC 1158-2.
3 Normative References
This specification makes dated and undated references to specifications in other
publications. These normative references are located at the respective points in
the text and the publications are named accordingly. In case of fixed
references, later changes or revised versions of these publications only belong
to this specification if they are worked in through changes or revised versions.
For undated references the last edition is valid.
ISO 7498 : 1984 Information processing systems; Open Systems Intercon-
nection; Basic Reference Model
IEC 1158-2 :1993 Fieldbus standard for use in industrial control systems
- Part 2: Physical Layer specification and service
definition
DIN EN 50020 Electrical apparatus for potentially explosive atmos-
pheres - intrinsic safety "i"
4 General
4.1 Definitions
The definitions of the PROFIBUS Specification and of IEC 1158-2 apply.
4.2 Abbreviations
Note that the Physical Layer is no longer abbreviated as ”PHY”, but as ”PhL” in
accordance with IEC 1158-2. ”Ph-” is used as the prefix for service primitives.
Abbreviations used :
CRC Cyclic Redundancy Check
DCE Data Communication Equipment
DTE Data Terminal Equipment
MAU Medium Attachment Unit
MDS Medium Dependent Sublayer
PhICI Physical Layer Interface Control Information
Ph- Physical-
PhL Physical Layer
PhID Physical Layer Interface Data
PhIDU Physical Layer Interface Data Unit
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PhPCI Physical Layer Protocol Control Information
SDF Start Delimiter Data Link
SDL 1 Start Delimiter 1 Data Link
SDL 2 Start Delimiter 2 Data Link
SDL 3 Start Delimiter 3 Data Link
SDL 4 Start Delimiter 4 Data Link
SDL 5 Start Delimiter 5 Data Link
T
PTG
Post-transmission gap time
Refer also to IEC 1158-2 clause 4 as well as PROFIBUS Specification, Part 2,
subclause 3.1.2.
4.3 Basic Properties
The same basic features shall apply as described in PROFIBUS Specification,
Part 2, subclause 3.2.
5 Characteristic Features
Beside the requirements of the application field explained in subclause 3.3 of
PROFIBUS Specification, Part 2, this specification has to enable intrinsically
safe data transmission and power supply over the bus. This results in the
characteristic features described as follows:
Network topology: Linear bus, terminated at both ends, with or
without stubs and branches (tree)
Medium, distances,
number of stations: according to IEC 1158-2, subclause 11.2.2, rules 1
to 3, the following values shall apply:
- non-intrinsically safe fieldbus with and without
power supply: 2 to 32 devices
- intrinsically safe fieldbus with power supply:
limitations on the number of stations is the
result of the limited electrical power that
intrinsically safe circuits are able to transfer.
- The distance between two stations, when the
maximum number of stations is connected, is at
most 1.9 km including the stubs.
Transmission speed: 31.25 kbit/s for distances up to 1,900 m
Redundancy: with second medium
Transmission
characteristics: Half duplex, synchronous, self-clocking,
Manchester-Biphase-L-Coding
Addressing, station types,
bus access, data transfer
services, frame length,
data integrity: according to PROFIBUS Specification, Part 2,
subclause 3.3