Спецификация протокола Profibus
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Requester Receiver 1
Master . Master/Slave
.
User!FMS LLI FDL BUS FDL LLI FMS!User
=====!====!==============!======.======!==============!====!=====
INFO.req ! ! ! !
<#5,Pri- ! ! ! !
ority> ! ! ! !
----> ! ! ! !
[INFO_REQ_! ! ! !
PDU] ! ! ! !DTU.ind
! ! ! !<#8,LLI
---->![DTU_REQ_PDU] !**INFO_REQ_ ! !SAP,Pri-
DTU.req ! ! PDU ! !ority,
<#5,LLI ! !*DTU_REQ_PDU ! !INFO_REQ_
SAP,Pri- !(FDL_DATA.req)![SDN_REQ_PDU]!(FDL_DATA.ind)!PDU>
ority, ! ]------->!--+--+------>!------------->!--->
INFO_ ! [<-------!--) ! ! ! INFO.ind
REQ_PDU> !(FDL_DATA.con)! ! ! ! <#8,Pri-
! ! ! ! ! ority>
! ! ! ------>
! ! !
! !
! ! Receiver 2
! ====================!====.=====
! ! !
! ! !
! ! !
+----->]! !
! ! !
! ! !
! ! !
! !
! ! Receiver n
! ====================!====.=====
! ! !DTU.ind
! ! !<#6,LLI
! ! !SAP,Pri-
! ! !ority,
! ! !INFO_REQ_
! !(FDL_DATA.ind)!PDU>
+------>!------------->!--->
! ! INFO.ind
! ! <#6,Pri-
! ority>
! ---->
!
Figure 92. Multicast Communication Relationship / Mapping of an unconfirmed FMS
Service for the Example of InformationReport Service / Receiver 2 is
not member of this Multicast Station Group
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6.5 LLI PDUs
LLI distinguishes between ten different PDU Types by unique function codes (FC).
The assignment of function codes to PDU types is shown in the table below.
Table 20. Coding of the LLI PDU Types
+======+=======================================================+
! FC ! LLI PDU Type !
+======+=======================================================+
! 0000 ! Associate Request PDU (ASS_REQ_PDU) !
+------+-------------------------------------------------------+
! 0001 ! Associate Response PDU (ASS_RES_PDU) !
+------+-------------------------------------------------------+
! 0010 ! Associate Negative Response PDU (ASS_NRS_PDU) !
+------+-------------------------------------------------------+
! 0011 ! Abort Request PDU (ABT_REQ_PDU) !
+------+-------------------------------------------------------+
! 0100 ! Data Transfer Confirmed Request PDU (DTC_REQ_PDU) !
+------+-------------------------------------------------------+
! 0101 ! Data Transfer Confirmed Response PDU (DTC_RES_PDU) !
+------+-------------------------------------------------------+
! 0110 ! Data Transfer Acknowledged Request PDU (DTA_REQ_PDU) !
+------+-------------------------------------------------------+
! 0111 ! Data Transfer Acknowledged Acknowledge PDU !
! ! (DTA_ACK_PDU) !
+------+-------------------------------------------------------+
! 1000 ! Data Transfer Unconfirmed Request PDU (DTU_REQ_PDU) !
+------+-------------------------------------------------------+
! 1001 ! Idle Request PDU (IDLE_REQ_PDU) !
+------+-------------------------------------------------------+
Every LLI PDU consists of a number of octets. The significance of each bit
within an octet is defined in the figure below.
Significance MSB LSB
+----+----+----+----+----+----+----+----+
! ! ! ! ! ! ! ! !
+----+----+----+----+----+----+----+----+
Bit Number: b8 b7 b6 b5 b4 b3 b2 b1
Figure 93. Significance of the bits within an octet
In the following PDU descriptions the octet 1 shall always be transmitted first.
The general structure of a LLI PDU is shown in the following figure.
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! Octet 1 !
!MSB LSB!
+---------+--------+--------+------+-----------+-----------!--//
! Length !Reserved!Reserved! LLI ! LLI ! Length !
!Extension! ! ! SAP ! Function ! Extension !
! Bit ! Bit ! Bit ! ! Code ! Octet !
+---------+--------+--------+------+-----------+-----------+--//
! 1 bit ! 1 bit ! 1 bit ! 1 bit! 4 bits ! 0/1 octet !
//--+----------------+----------------+
! ! !
! LLI Info ! LLI User PDU !
! ! !
//--+----------------+----------------+
! 0 to n octets ! 0 to m octets !
Figure 94. General Structure of a LLI PDU
Meaning of the fields of a LLI PDU:
Length Extension Bit
This field of length 1 bit shall indicate whether the fields Length Extension
Octet and LLI Info are present. If the field Length Extension Bit has the value
0, then the fields Length Extension Octet and LLI Info are absent. If the field
Length Extension Bit has the value 1, then the fields Length Extension Octet and
LLI Info are present.
Reserved Bit
These fields each of length 1 bit are reserved for future use.
LLI SAP
This field of length 1 bit shall specify the LLI SAP which is configured in the
CRL of the sending LLI for this communication relationship. The LLI SAP 0 is al-
ways assigned to the LLI user FMS. The LLI SAP 1 is always assigned to the LLI
user FMA7.
LLI Function Code
This field shall contain the function code of the LLI PDU.
Length Extension Octet
This field gives the length of the field LLI Info in octets. The Length Exten-
sion Octet and the field LLI Info are only present if the Length Extension Bit
has the value 1.
LLI Info
This field contains further LLI protocol information.
LLI User PDU
This field shall contain the PDU from the LLI user.
Octet Octet Octet Octet
! 1 ! 2 ! 3 to 11 ! 12 to z
+---+---+---+------+------+-------+----------+----------------+
! 1 ! 0 ! 0 ! LLI ! 0000 ! 9 ! LLI ! LLI User !
! ! ! ! SAP ! ! ! Context ! PDU !
+---+---+---+------+------+-------+----------!----------------+
1 1 1 1 4 1 9 n
bit bit bit bit bits octet octets octets
Figure 95. Structure of the ASS_REQ_PDU
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Octet Octet Octet Octet Octet Octet
3 4 5 6 7 8 to 11
+------+---------+---------+---------+---------+---------+
! Type ! MAX_SCC ! MAX_RCC ! MAX_SAC ! MAX_RAC ! ACI !
+------+---------+---------+---------+---------+---------+
1 octet 1 octet 1 octet 1 octet 1 octet 4 octets
ACI:
+---------+---------+----------+----------+
! Octet 8 ! Octet 9 ! Octet 10 ! Octet 11 !
+---------+---------+----------+----------+
MS byte LS byte
Figure 96. Structure of the Field LLI Context of the ASS_REQ_PDU
The field Type shall indicate the type of the communication relationship (see
LLI CRL definition) and may contain the following values:
Table 21. Coding for the Field Type
b8 b1 <- bit position
0 0 0 0 0 0 0 0 : MMAC
0 0 0 0 0 0 0 1 : MSAC
0 0 0 0 0 1 0 1 : MSAC_SI
0 0 0 0 0 0 1 1 : MSCY
0 0 0 0 0 1 1 1 : MSCY_SI
The fields "MAX_SCC", "MAX_RCC", "MAX_SAC" and "MAX_RAC" may take the values 0
to 255 and shall be coded as Unsigned8.
The value of ACI shall be multiplied by 10 ms to determine the control interval
for the Idle Control and shall be coded as Unsigned32.
(Range: 0 ms to (10 * (2**32 - 1)) ms).
Octet Octet
! 1 ! 2 to z !
+---+---+---+------+------+-----//------+
! 0 ! 0 ! 0 ! LLI ! 0001 ! LLI User !
! ! ! ! SAP ! ! PDU !
+---+---+---+------+------+-----//------+
1 1 1 1 4 n
bit bit bit bit bits octets
Figure 97. Structure of the ASS_RES_PDU
Octet Octet
! 1 ! 2 to z !
+---+---+---+------+------+-----//------+
! 0 ! 0 ! 0 ! LLI ! 0010 ! LLI User !
! ! ! ! SAP ! ! PDU !
+---+---+---+------+------+-----//------+
1 1 1 1 4 n
bit bit bit bit bits octets
Figure 98. Structure of the ASS_NRS_PDU
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Octet Octet Octet Octet Octet
! 1 ! 2 ! 3 ! 4 ! 5 to z !
+---+---+---+------+------+-------+-------+-------+-----------+
! 1 ! 0 ! 0 ! LLI ! 0011 ! 2 + n !Ident- !Reason !Additional !
! ! ! ! SAP ! ! !ifier ! Code ! Detail !
+---+---+---+------+------+-------+-------+-------+-----------+
1 1 1 1 4 1 1 1 0 to 16
bit bit bit bit bits octet octet octet octets
Figure 99. Structure of the ABT_REQ_PDU
Identifier
This field shall indicate the reason for the connection release and may contain
the following values:
Table 22. Coding for the Field Identifier
b8 b1 <- bit position
0 0 0 0 0 0 0 0 : User
0 0 0 0 0 0 0 1 : LLI User
0 0 0 0 0 0 1 0 : LLI
0 0 0 0 0 0 1 1 : Layer 2
Reason Code
This field shall indicate the reason for the connection release depending on the
identifier.
Table 23. Coding for the Field Reason Code
If the reason lies in Layer 2, then the field Reason Code shall contain the
L_status and may take the following values:
b8 b1 <- bit position
0 0 0 0 0 0 0 0 : RR
0 0 0 0 0 0 0 1 : LR
0 0 0 0 0 0 1 0 : NA
0 0 0 0 0 0 1 1 : RDL
0 0 0 0 0 1 0 0 : RDH
If the reason is located in LLI, then the field Reason Code may take the follow-
ing values:
b8 b1 <- bit position
0 0 0 0 0 0 0 0 : ABT_RC1
0 0 0 0 0 0 0 1 : ABT_RC2
0 0 0 0 0 0 1 0 : ABT_RC3
to to
0 0 0 0 1 0 1 1 : ABT_RC12
If the reason is located at the LLI user or at the user, then the field Reason
Code may take the following values:
b8 b1 <- bit position
0 0 0 0 0 0 0 0 : ABT_RC1
0 0 0 0 0 0 0 1 : ABT_RC2
0 0 0 0 0 0 1 0 : ABT_RC3
to to
1 1 1 1 1 1 1 1 : ABT_RC256
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Additional Detail
This field shall contain additional details about the connection release depend-
ing on the identifier and Reason Code.
If the reason is located in Layer 2, then the field Additional Detail is omit-
ted.
If the reason is located in LLI and the Reason Code indicates LLI-LLI context
test negative, then the field Additional Detail shall contain the LLI context of
the requester of the release (9 octets). For all other reason codes the field
Additional Detail shall be omitted.
If the reason is located at the LLI user then the field Additional Detail shall
contain the value (max. 16 octets) given by the LLI user.
If the reason is located at the user, then the field Additional Detail shall
contain the value (max. 16 octets) given by the LLI User.
Octet Octet
! 1 ! 2 to z !
+---+---+---+------+------+-----//------+
! 0 ! 0 ! 0 ! LLI ! 0100 ! LLI User !
! ! ! ! SAP ! ! PDU !
+---+---+---+------+------+-----//------+
1 1 1 1 4 n
bit bit bit bit bits octets
Figure 100. Structure of the DTC_REQ_PDU
Octet Octet
! 1 ! 2 to z !
+---+---+---+------+------+-----//------+
! 0 ! 0 ! 0 ! LLI ! 0101 ! LLI User !
! ! ! ! SAP ! ! PDU !
+---+---+---+------+------+-----//------+
1 1 1 1 4 n
bit bit bit bit bits octets
Figure 101. Structure of the DTC_RES_PDU
Octet Octet
! 1 ! 2 to z !
+---+---+---+------+------+-----//------+
! 0 ! 0 ! 0 ! LLI ! 0110 ! LLI User !
! ! ! ! SAP ! ! PDU !
+---+---+---+------+------+-----//------+
1 1 1 1 4 n
bit bit bit bit bits octets
Figure 102. Structure of the DTA_REQ_PDU
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Octet
! 1 !
+---+---+---+------+------+
! 0 ! 0 ! 0 ! LLI ! 0111 !
! ! ! ! SAP ! !
+---+---+---+------+------+
1 1 1 1 4
bit bit bit bit bits
Figure 103. Structure of the DTA_ACK_PDU
Octet Octet
! 1 ! 2 to z !
+---+---+---+------+------+-----//------+
! 0 ! 0 ! 0 ! LLI ! 1000 ! LLI User !
! ! ! ! SAP ! ! PDU !
+---+---+---+------+------+-----//------+
1 1 1 1 4 n
bit bit bit bit bits octets
Figure 104. Structure of the DTU_REQ_PDU
Octet
! 1 !
+---+---+---+------+------+
! 0 ! 0 ! 0 ! LLI ! 1001 !
! ! ! ! SAP ! !
+---+---+---+------+------+
1 1 1 1 4
bit bit bit bit bits
Figure 105. Structure of the IDLE_REQ_PDU
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6.6 Start of LLI
After power-on, or after the LLI is reset from the FMA7, the start of the LLI
begins. The starting phase is processed by the basic state machine of the LLI.
Only after attaining the READY state is the LLI ready for operation and may ac-
cept requests for connection establishment or connectionless communication serv-
ices (Broadcast / Multicast).
6.6.1 Conditions of Readiness for Operation
The following conditions shall be fulfilled for the successful termination of
the starting phase (State of the LLI Basic State Machine = READY):
- Static part of the LLI CRL is present.
- Sufficient resources are available for the dynamic part of the LLI CRL.
- Sufficient resources are available for the Poll List and the LSAP Configura-
tions.
- Sufficient resources are available for timers, buffers and state machines etc.
6.6.2 Predefinition of the dynamic part of the LLI CRL
In the starting phase the dynamic part of the LLI CRL is created and predefined
by the LLI. For a connection-oriented communication relationship the predefini-
tion is shown in the following figure. For a broadcast/multicast communication
relationship the predefinition is shown in the second next figure.
+==+======+=========+======================+====================+
! !MANDA-! !Status ! Closed !
! !TORY ! ! ! !
! +------+ +----------------------+--------------------+
! ! ! !Actual Remote Address ! - - !
! ! ! +----------------------+--------------------+
! ! ! !Actual Remote LSAP ! - - !
! ! ! At- +----------------------+--------------------+
! ! C ! tributes!SCC ! Null !
! ! O ! for +----------------------+--------------------+
!D ! N ! Admin- !RCC ! Null !
!Y ! D ! istra- +----------------------+--------------------+
!N ! I ! tion !SAC ! Null !
!A ! T ! of the +----------------------+--------------------+
!M ! I ! Communi-!RAC ! Null !
!I ! O ! cation +----------------------+--------------------+
!C ! N ! Rela- !IMA ! false !
! ! A ! tion- +---------+------------+--------------------+
! ! L ! ship !Image !Request ! - - !
! ! ! used !Data !Invoke ID ! !
! ! ! inter- !Memory +------------+--------------------+
! ! ! nally !(IDM) !FMS PDU ! - - !
! ! ! by LLI ! ! ! !
! ! ! +---------+------------+--------------------+
! ! ! ! Poll Entry Enabled ! false !
! ! ! +----------------------+--------------------+
! ! ! ! New ! - - !
! ! ! +----------------------+--------------------+
! ! ! ! Old ! - - !
+==+======+=========+======================+====================+
Figure 106. Predefinition of dynamic Part of the CRL for a Connection-oriented
Communication Relationship
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+==+===============+=======================+====================+
!D !MANDATORY !Status ! CONLS-REQUESTER/ !
! ! ! ! CONLS-RECEIVER !
+==+===============+=======================+====================+
Figure 107. Predefinition of dynamic Part of the CRL for a Broad/Multicast Com-
munication Relationship
6.6.3 Generation of the Poll List and Transfer to Layer 2
In the starting phase the LLI creates the Poll List (see PROFIBUS Data Link
Layer) depending on the master-slave communication relationships in the CRL. The
multiplier value in the CRL shall be considered thereby for multiple entries.
The Poll List is delivered to Layer 2 with a FDL_CYC_DATA_REPLY.req service
primitive. The necessary Service Access Point, the Poll List LSAP, shall be de-
fined in the header of the LLI CRL.
6.6.4 Activation of Service Access Points of Layer 2
The Service Access Points of Layer 2 shall be activated in the start-up phase by
LLI. The LLI of the master calls the service SAP Activate FMA1/2 for all LSAPs.
The LLI of the slave calls for all RSAPs the service RSAP Activate FMA1/2 and
for all LSAPs the service SAP Activate FMA1/2.
The following conditions apply in setting the LSAP parameters:
At the master
- For every master - master communication relationship for acyclic data transfer
with the connection attribute = "D or O" which is registered in the LLI CRL, a
LSAP with the following parameters shall be activated:
Access: Rem_add, if connection attribute = "D"
All, if connection attribute = "O"
Service: SDA, Role_in_service = Both
The values of the other parameters result from the entries of the master - ma-
ster communication relationships in the static part of the LLI CRL.
- For master - master communication relationships for acyclic data transfer with
the connection attribute = "I", the assigned LSAP of the Layer 2 shall not be
activated in the start-up phase of LLI.
- All master - slave communication relationships shall be registered in the Poll
List of Layer 2. The Poll List LSAP of Layer 2 shall be activated with the
following parameters:
Access: All
Service: CSRD, Role_in_service = Initiator
SRD, Role_in_service = Initiator, if for a connection the max PDU
length for high priority messages is configured to be larger than 0.
Confirm_mode: Data
The values of the other parameters result from the entries of the master -
slave communication relationships in the static part of the LLI CRL.
- For all broadcast or multicast communication relationships as a requester an
individual LSAP shall be activated with the following parameters:
Access: All
Service: SDN, Role_in_service = Initiator
The values of the other parameters results from the entries of the broadcast-
or multicast communication relationships in the static part of the LLI CRL.
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- For all broadcast communication relationships as a receiver the LSAP 63 shall
be activated with the following parameters:
Access: All
Service: SDN, Role_in_service = Responder
The values of the other parameters result from the entries of the broadcast
communication relationships in the static part of the LLI CRL.
- For every multicast communication relationship as a receiver the assigned
LSAP shall be activated with the following parameters:
Access: All
Service: SDN, Role_in_service = Responder
The values of the other parameters result from the entries of the multicast
communication relationships in the static part of the LLI CRL.
At the slave
- For every communication relationship of type MSAC or MSCY which is registered
in the CRL, the assigned RSAP shall be activated with the service RSAP Acti-
vate FMA1/2 with the following parameters:
Access: Rem_add, if connection attribute = "D"
All, if connection attribute = "O"
Indication_mode: Data
The values of the other parameters result from the entries of the master -
slave communication relationships in the static part of the LLI CRL.
- For all broadcast communication relationships as a receiver, the LSAP 63
shall be activated with the following parameters:
Access: All
Service: SDN, Role_in_service = Responder
The values of the other parameters result from the entries of the broadcast
communication relationships in the static part of the LLI CRL.
- For every multicast communication relationship as a receiver, the assigned
LSAP shall be activated with the following parameters:
Access: All
Service: SDN, Role_in_service = Responder
The values of the other parameters result from the entries of the multicast
communication relationships in the static part of the LLI CRL.
6.7 Formal Description of the LLI State Machines
The formal description of LLI is based upon a model. It describes the LLI proto-
col with the help of state machines (represented by state diagrams). The proto-
col sequences are described by different states (represented by ellipses with
the name of the state) and transitions between states (represented by lines with
arrows). State changes are caused by events (for example time out) combined with
conditions. The state changes in turn lead to actions or reactions.
Three different kinds of state machines are distinguished between:
a) the basic state machine of the LLI (start)
b) the CREF related state machines (connection establishment, open,
connection release, DTU)
c) the service related state machines (DTC, DTCC, DTA, IDLE)
The description of the state transitions is similar to the draft ISO 8802 Part
4. The elements used are the sequence (current state, event / condition => ac-
tion, next state) as well as constants, variables, service primitives, functions
and procedures.
The detailed description of the state transitions and actions is structured for
every state change as follows:
The first line defines the current state, the name of the transition and the
next state. Below, in the subsequent lines, shall follow: