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Max L_sdu Lengths

The maximum Lsdu lengths (a to d) shall be calculated by FMA7 related according

to user declarations and entered into the CRL. The values shall be in the range

of 0 to 242 bytes.

a) Maximum L_sdu length for high priority PDUs to be sent

It indicates the maximum length of a L_sdu with which a high priority LLI PDU

may be sent. The value 0 shall be specified here for communication relationships

which do not use high priority LLI user services.

b) Maximum L_sdu length for low priority PDUs to be sent

It indicates the maximum length of a L_sdu with which a low priority LLI PDU may

be sent.

c) Maximum L_sdu length for low priority PDUs to be received

It indicates the maximum length of a L_sdu with which a high priority LLI PDU

may be received. The value 0 shall be specified here for communication relation-

ships which do not use high priority LLI user services.

d) Maximum L_sdu length for low priority PDUs to be received

It indicates the maximum length of a L_sdu with which a low priority LLI PDU may

be received.

LLI Context

The LLI context contains the attributes of a communication relationship, which

shall be compatible with the corresponding attributes of the communication part-

ner.

+------+---------+---------+---------+---------+-----+

! TYPE ! max SCC ! max RCC ! max SAC ! max RAC ! ACI !

+------+---------+---------+---------+---------+-----+

Figure 30. LLI Context.

TYPE specifies the type of a communication relationship:

- MMAC : master-master connection for acyclic data transfer

- MSAC : master-slave connection for acyclic data transfer with

no slave initiative

- MSAC_SI : master-slave connection for acyclic data transfer with

slave initiative

- MSCY : master-slave connection for cyclic data transfer with

no slave initiative (see note in subclause 4.3.1.2)

- MSCY_SI : master-slave connection for cyclic data transfer with

slave initiative (see master master communication relationship)

- BRCT : Broadcast communication relationship

- MULT : Multicast communication relationship

Slave initiative (SI) means that the slave may initiate the LLI service "DTA".

max SCC (maximum value of Send Confirmed Request Counter)

On connections for acyclic data transfer at the master, this attribute specifies

the permitted maximum number of parallel confirmed LLI user services to the re-

mote communication partner (outstanding responses of the remote LLI). This cor-

responds to the necessary number of DTC requester state machines. In all other

cases max SCC has the value 0.

max RCC (maximum value of Receive Confirmed Request Counter)

At the master (master-master communication relationship) or at the slave this

attribute specifies for connections for acyclic data transfer the maximum per-

mitted number of parallel confirmed LLI user services of the remote communica-

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tion partner (outstanding responses of the LLI user). This corresponds to the

necessary number of DTC responder state machines. In all other cases max RCC has

the value 0.

max SAC (maximum value of Send Acknowledged Request Counter)

For all types of connections this attribute specifies the permitted maximum num-

ber of parallel unconfirmed LLI user services to the remote communication part-

ner (outstanding acknowledges of the remote LLI). This corresponds to the neces-

sary number of DTA requester state machines.

For slave stations with no initiative and for connectionless relationships max

SAC has the value 0.

max RAC (max. value of Receive Acknowledged Request Counter)

For all types of connections this attribute specifies the maximum permitted num-

ber of unconfirmed LLI user services of the remote communication partner (out-

standing free buffer). This corresponds to the necessary number of DTA acknowl-

edge state machines).

At the master of a master-slave communication relationship with no slave initia-

tive and for connectionless communication relationships max RAC has the value 0.

ACI (Acyclic Control Interval)

This attribute specifies the receive control interval time for the idle connec-

tion control on connections for acyclic data transfer (see subclause 4.3.4.3.2).

If the connection control shall not be activated, the value 0 shall be config-

ured here. For connections for cyclic data transfer and for all connectionless

communication relationships the value 0 shall be configured for ACI.

LLI-SAP

This attribute specifies the LLI SAP which is configured for this communication

relationship. If this attribute has the value 0, the assigned LLI user is FMS.

If this attribute has the value 1, the assigned LLI user is FMA7. The LLI users

are statically assigned to a LLI SAP (see section 2.1).

CCI (Cyclic Control Interval)

This attribute specifies the control interval time of the connection control on

connections for cyclic data transfer (see subclause 4.3.4.3.2).

If this control shall not be executed at a slave, the value 0 shall be config-

ured here.

This attribute is not necessary for connections for acyclic data transfer and

for all connectionless communication relationships.

Multiplier

For connections for cyclic data transfer at the master side, this attribute

specifies how often the remote address (Rem_add) and the associated remote LSAP

(DSAP) of this CREF shall be entered in the Poll List. The poll interval of

Layer 2 may be shortened by this means. It allows connections to be prioritized

over other connections for cyclic data transfer. The range of attribute values

comprises all values between 1 and 255.

The multiplier is not necessary for all other communication relationships.

Connection attribute

It contains further information about the connection type for connection-

oriented communication relationships (see connection attributes). The range of

values comprises the values "D", "I" and "O".

"D" : defined connection (master-master- or master-slave connection)

"I" : open connection at the requester (master-master connection)

"O" : open connection at the responder (master-master- or

master-slave connection)

This attribute is not necessary for connectionless communication relationships.

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Maximum length for low priority LLI user PDUs to be received

For connections for cyclic data transfer this attribute specifies the maximum

length of the low priority LLI user PDUs to be received in order to define the

size of the Image Data Memory (IDM). The attribute is not necessary for all

other communication relationships.

The structure of the dynamic part of the CRL (entries) is shown in the table be-

low:

+==+======+=========+======================+======+==//==+======+

! !MANDA-! !Status ! ! ! !

! !TORY ! ! ! ! ! !

! +------+ +----------------------+------+--//--!------+

! ! ! !Actual Remote Address ! ! ! !

! ! ! !Actual Remote LSAP ! ! ! !

! ! ! At- +----------------------+------+--//--+------+

! ! ! tributes!SCC ! ! ! !

! ! ! used +----------------------+------+--//--+------+

! ! C ! intern- !RCC ! ! ! !

!D ! O ! ally by +----------------------+------+--//--+------+

!Y ! N ! LLI !SAC ! ! ! !

!N ! D ! for +----------------------+------+--//--+------+

!A ! I ! Admin- !RAC ! ! ! !

!M ! T ! istra- +----------------------+------+--//--+------+

!I ! I ! tion !IMA ! ! ! !

!C ! O ! of the +---+------------------+------+--//--+------+

! ! N ! Communi-! I ! Request Invoke ID! ! ! !

! ! A ! cation ! D +------------------+------+--//--+------+

! ! L ! Rela- ! M ! LLI User PDU ! ! ! !

! ! ! tion- +---+------------------+------+--//--+------+

! ! ! ship ! Poll Entry Enabled ! ! ! !

! ! ! +----------------------+------+--//--+------+

! ! ! ! New ! ! ! !

! ! ! +----------------------+------+--//--+------+

! ! ! ! Old ! ! ! !

+==+======+=========+======================+======+==//==+======+

Figure 31. Structure of the LLI CRL (Entries), dynamic Part

Meaning of the attributes in the dynamic part of the LLI CRL:

The attributes in the dynamic part of the LLI CRL are administered only by the

LLI internally. They shall not be configured.

Status

This attribute contains the status of all state machines of the communication

relationship.

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+-------------------------------+-----------+-----------+---//

! CN Estab. / CN Release / Open ! DTC Req.1 ! DTC Req.2 !

+-------------------------------+-----------+-----------+---//

//---+-----------+-----------+-----------+---//

! DTC Req.m ! DTC Res.1 ! DTC Res.2 !

//---+-----------+-----------+-----------+---//

! DTC Res.n ! DTA Req.1 ! DTA Req.2 !

//---+-----------+-----------+-----------+---//

! DTA Req.o ! DTA Ack.1 ! DTA Ack.2 !

//---+-----------+-----------+-----------+---//

//---+-----------+----------+

! DTA Ack.p ! IDLE.req !

//---+-----------+----------+

Estab. = Establishment, m = max SCC, n = max RCC, o = max SAC,

p = max RAC

Figure 32. Structure of the Status Attribute for Connections(CN) for Acyclic

Data Transfer at the Master

For master-slave connections the status attributes DTC-Res.1 to m are omitted.

For master-slave connections with no slave initiative the status attributes DTA-

Ack.1 to p are omitted.

+-------------------------------+-----------+-----------+---//

! CN Estab. / CN Release / Open ! DTC Res.1 ! DTC Res.2 !

+-------------------------------+-----------+-----------+---//

//---+-----------+-----------+-----------+---//

! DTC Res.n ! DTA Req.1 ! DTA Req.2 !

//---+-----------+-----------+-----------+---//

! DTA Req.o ! DTA Ack.1 ! DTA Ack.2 !

//---+-----------+-----------+-----------+---//

//---+-----------+----------+

! DTA Ack.p ! IDLE.req !

//---+-----------+----------+

Estab. = Establishment, n = max RCC,o = max SAC, p = max RAC

Figure 33. Structure of the Status Attribute for Connections (CN) for Acyclic

Data Transfer at the Slave

For master-slave connections with no slave initiative the status attributes DTA-

Req.1 to o are omitted.

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+-------------------------------+----------+-----------+---//

! CN Estab. / CN Release / Open ! DTC Req. ! DTA Req.1 !

+-------------------------------+----------+-----------+---//

//---+-----------+-----------+-----------+--//---+-----------+

! DTA Req.o ! DTA Ack.1 ! DTA Ack.2 ! ! DTA Ack.p !

//---+-----------+-----------+-----------+--//---+-----------+

Estab. = Establishment, o = max SAC, p = max RAC

Figure 34. Structure of the Status Attribute for Connections for Cyclic Data

Transfer at the Requester (Master)

For master-slave connections with no slave initiative the status attributes DTA-

Ack.1 to p are omitted.

+-------------------------------+----------+-----------+---//

! CN Estab. / CN Release / Open ! DTC Res. ! DTA Req.1 !

+-------------------------------+----------+-----------+---//

//---+-----------+-----------+-----------+--//---+-----------+

! DTA Req.o ! DTA Ack.1 ! DTA Ack.2 ! ! DTA Ack.p !

//---+-----------+-----------+-----------+--//---+-----------+

Estab. = Establishment, o = max SAC, p = max RAC

Figure 35. Structure of the Status Attribute for Connections for Cyclic Data

Transfer at the Responder (Slave)

For master-slave connections with no slave initiative the status attributes DTA-

Req.1 to o are omitted.

Structure of the Status Attribute for a Broadcast / Multicast

Communication Relationship at the Requester:

+---------------+

! DTU Requester !

+---------------+

Structure of the Status Attribute for a Broadcast / Multicast

Communication Relationship at the Receiver:

+--------------+

! DTU Receiver !

+--------------+

Figure 36. Structure of the Status Attribute for a Connectionless Communication

Relationship

Actual Remote Address

For connections with the connection attribute "O" which are not in the state

"CLOSED" (see connection establishment and release), this attribute contains the

FDL address (Rem_add, range of values 0 to 126) of the communication partner

with has initiated the connection establishment for this CREF. In all other

cases this attribute is not necessary.

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Actual Remote LSAP

For connections with the connection attribute "O" which are not in the state

"CLOSED", this attribute contains the local LSAP (DSAP range of values 0, 2 to

62) of the communication partner which has initiated the connection establish-

ment for this CREF. In all other cases this attribute is not necessary.

SCC (Send Confirmed Request Counter)

For connections for acyclic data transfer at the master this attribute specifies

the number of DTC requester state machines which are currently in use (i.e. not

in the state "DTC-WAIT-FOR-REQ"). In all other cases SCC is not necessary.

RCC (Receive Confirmed Request Counter)

For connections for acyclic data transfer at the master (master-master communi-

cation relationships) or at the slave, this attribute specifies the number of

DTC responder state machines which are currently in use (i.e. not in the state

"DTC-WAIT-FOR-REQ-PDU"). In all other cases RCC is not necessary.

SAC (Send Acknowledged Request Counter)

For connections this attribute specifies the number of DTA requester state ma-

chines which are currently in use (i.e. not in the state "DTA-WAIT-FOR-REQ). For

slave stations with no initiative and for connectionless communication relation-

ships SAC is not necessary.

RAC (Receive Acknowledged Request Counter)

For connections this attribute specifies the number of DTA acknowledge state ma-

chines which are currently in use (i.e. not in the state "DTA-WAIT-FOR-REQ-

PDU"). For the master of a master-slave connection with no slave initiative and

for connectionless communication relationships RAC is not necessary.

IMA (Idle Machine Activated)

On connections for acyclic data transfer with connection control this attribute

specifies whether the Idle state machine is in use (i.e. not in the state "IDLE-

WAIT-FOR-REQ").

This attribute may take the following values:

false: Idle State machine is in the state "IDLE-WAIT-FOR-REQ".

true : Idle state machine is not in the state "IDLE-WAIT-FOR-REQ".

For all communication relationships which do not perform idle control this at-

tribute is not necessary.

IDM (Image Data Memory)

The image data memory is only used by the LLI on connections for cyclic data

transfer. For all other communication relationships this attribute is not neces-

sary.

Request Invoke ID

The LLI of the requester stores the Invoke ID of the LLI user request PDU here.

LLI user PDU

The LLI of the requester stores the LLI user response PDU here. The LLI of the

responder stores the LLI user request PDU here. The size of this attribute cor-

responds to the maximum LLI user PDU length for low priority messages to be re-

ceived, see static part of the CRL.

Poll Entry Enabled

The attribute Poll Entry Enabled (PEE) is used by the LLI at the master of a

master slave connection to administer the status of the Poll List entry of this

communication reference.

This attribute may take the following values:

false: The Poll List entry in Layer 2 is locked, i.e. the registered

station (Rem_add/DSAP) is not polled.

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true: The Poll List entry is unlocked, i.e. the registered

station (Rem_add/DSAP) is polled.

For all other communication relationships this attribute is not necessary.

New

This attribute is used by the LLI on master-slave connections for cyclic data

transfer at the slave to indicate the execution of a new request (receipt of a

DTC_REQ_PDU with new Invoke ID).

This attribute may take the following values:

true : A new request is being executed.

false: A current request is being executed cyclically.

Old

This attribute is used by the LLI on master-slave connections for cyclic data

transfer at the slave to indicate the execution of the current request after re-

ceipt of a new request (receipt of a DTC_REQ_PDU with new Invoke ID).

This attribute may take the following values:

true : An already active order is executed after receiving a new request.

false: A current request is being executed cyclically.

For all other communication relationships this attribute is not necessary.

6.2.6.2 Connection Attribute

For connection oriented communication relationships the LLI distinguishes three

types of values of the connection attribute:

"D" : Defined connection

For a defined connection the communication partner is uniquely defined by enter-

ing the remote address (Rem_add) and the assigned LSAP (DSAP) in the static part

of the CRL at the time of configuration. Thereby the access protection of

Layer 2 (see PROFIBUS Data Link Layer definition) is permitted in all three

phases of the communication relationship.

"O" : Open connection at the Responder

For open connections no communication partner is defined at the responder at the

time of configuration. In the static part of the CRL the value "ALL" is config-

ured for the remote address and the remote LSAP. So every requester which is

configured is permitted to request a connection establishment from the re-

sponder. If the LLI receives a request for connection establishment it takes the

values of the parameters Loc_add/SSAP from the indication primitive of Layer 2

and enters these into the attributes Actual Remote Address and Actual Remote

LSAP of the dynamic part of the LLI CRL. Then the access protection of Layer 2

is activated. Thereafter the connection behaves like a defined connection.

Upon release of the connection, it returns to the open state.

"I" : Open connection at the requester

If multiple master-master connections for acyclic data transfer use the same lo-

cal LSAP at different times, they are called "open connections at the re-

quester". At any time only one of these connections is permitted not to be in

the state "CLOSED". The activation of the local LSAP takes place first in the

connection establishment phase. Then this connection behaves like a defined con-

nection. The denomination "requester" or "responder" only refers to the connec-

tion establishment.

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6.2.6.3 Assignment of PDUs and Service Primitives to the Communication Reference

The LLI shall assign all PDUs which are received from Layer 2 and all service

primitives which are received from the LLI - LLI user interface to a communica-

tion reference which is registered in the LLI CRL.

The LLI shall assign a PDU which is received from Layer 2 to that CREF, for

which the value of the LLI SAP contained in the PDU and the values of the local

LSAP, the remote address and remote LSAP contained in the FDL primitive, are

equal to the values configured in the CRL. In addition for a CRL with the con-

nection attribute “I” a FMA service primitive shall be assigned to that CRL

whose state is currently not closed.

PDUs which cannot be assigned to a CREF shall be ignored by LLI.

The LLI assigns a service request, received from the LLI user, to the Layer 2

address (remote address, remote LSAP) contained in the LLI CRL entry.

The Layer 2 address is taken from the LLI CRL entry for which the values of CREF

and LLI SAP of the argument are equal to the values configured in the LLI CRL.

Service primitives at the LLI - LLI user interface which cannot be assigned to a

Layer 2 address shall be ignored by LLI and an error (LLI-Fault.ind) shall be

issued to FMA7.

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In order to allow a unique assignment the following conditions shall be ful-

filled by the configuration of the CRL:

Table 17. Assignment of Remote Address, Remote LSAP and Local LSAP to the CREF

+======+===========+==============+==============+==============+

! !Communica- ! Requester ! Responder/ ! Req. + Res./ !

! !tion Rela- ! ! Receiver ! Receiver !

!Group !tionship/ !Remote ! !Remote ! !Remote ! !

! !Connection !Address,!Local!Address,!Local!Address,!Local!

! !Attribute !Remote !LSAP !Remote !LSAP !Remote !LSAP !

! ! !LSAP ! !LSAP ! !LSAP ! !

+======+===========+========+=====+========+=====+========+=====+

! ! ! ! ! ! ! ! !

! !MMAC/D ! E ! E ! E ! E ! E ! E !

! ! ! ! ! ! ! ! !

! !-----------+--------+-----+--------+-----+--------+-----+

! ! ! ! ! ! !

! A !MMAC/I ! E ! M ! not allowed ! not allowed !

! ! ! ! ! ! !

! !-----------+--------+-----+--------+-----+--------------+

! ! ! ! ! ! !

! !MMAC/O ! not allowed ! M (All)! E ! not allowed !

! ! ! ! ! ! !

+======+===========+========+=====+========+=====+==============+

! !MSAC/D ! ! M ! ! ! !

! !MSAC_SI/D ! ! ! ! ! !

! !MSCY/D ! E !POLL ! M ! E ! not allowed !

! !MSCY_SI/D ! !LSAP ! ! ! !

! !-----------+--------+-----+--------+-----+--------------+

! !MSAC/I ! ! ! !

! !MSAC_SI/I ! ! ! !

! B !MSCY/I ! not allowed ! not allowed ! not allowed !

! !MSCY_SI/I ! ! ! !

! !-----------+--------------+--------+-----+--------------+

! !MSAC/O ! ! ! ! !

! !MSAC_SI/O ! ! ! ! !

! !MSCY/O ! not allowed ! M (All)! E ! not allowed !

! !MSCY_SI/O ! ! ! ! !

+======+===========+========+=====+========+=====+==============+

! ! ! ! ! ! ! !

! C ! BRCT ! M ! E ! E ! M ! not allowed !

! ! ! ! ! ! ! !

+======+===========+========+=====+========+=====+==============+

! ! ! ! ! ! ! !

! D ! MULT ! M ! E ! E ! M ! not allowed !

! ! ! ! ! ! ! !

+======+===========+========+=====+========+=====+==============+

! Explanations: !

! E : only allowed once Req. : Requester !

! M : allowed several times Res. : Responder !

+===============================================================+

The groups shall not use the same values for local LSAP and remote address / re-

mote LSAP respectively, with the exception of the remote address / remote LSAP:

All.

Every communication relationship entered in the LLI CRL shall specify a unique

Layer 2 address. Entries with the same Layer 2 address and different LLI SAPs

are not permitted.

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In the groups C and D the value All for the attributes remote address and/or re-

mote LSAP shall only be configured if there exists for the same local LSAP no

further CRL entry with a value unequal to All for this/these attributes.

6.2.6.4 Assignment of Types of Communication Relationships to the LLI User

Not all types of communication relationships are suitable for all LLI users in

the same way. Therefore, for the configuration of the CRL the following rules

shall apply:

Table 18. Assignment of Types of Communication Relationships to the LLI User

+====================+============+=======================+

! Type of Communica- ! permitted ! permissible values for!

! tion Relationship ! LLI User ! the Attribute LLI SAP !

+====================+============+=======================+

! MMAC ! FMS, FMA7 ! 0, 1 !

+--------------------+------------+-----------------------+

! MSAC ! FMS, FMA7 ! 0, 1 !

+--------------------+------------+-----------------------+

! MSAC_SI ! FMS ! 0 !

+--------------------+------------+-----------------------+

! MSCY ! FMS ! 0 !

+--------------------+------------+-----------------------+

! MSCY_SI ! FMS ! 0 !

+--------------------+------------+-----------------------+

! BRCT ! FMS ! 0 !

+--------------------+------------+-----------------------+

! MULT ! FMS ! 0 !

+--------------------+------------+-----------------------+

6.3 Connection-oriented Communication Relationships

For a connection-oriented communication relationship a logical one-to-one con-

nection exists between two communication partners. An application process ad-

dresses the connection using a local CREF. The connection shall be established

before it can be used for data transmission. If a connection is established and

is no longer needed for data transmission then it may be released. This connec-

tion-oriented method distinguishes between the three phases:

- connection establishment

- data transfer

- connection release.

The LLI makes the different functionalities of the connection-oriented communi-

cation relationships available to the LLI users. These functionalities need not

be used. LLI users may request them from the LLI as required.

6.3.1 Connection Types and Addressing

6.3.1.1 Master-Slave Communication Relationship

A connection is characterized by the mapping of the LLI user services onto Layer

2 services and their model behaviour within LLI. For a master - slave communica-

tion relationship the following kinds of connections are permitted:

- Connection for Cyclic Data Transfer with no Slave Initiative

- Connection for Cyclic Data Transfer with Slave Initiative

- Connection for Acyclic Data Transfer with no Slave Initiative

- Connection for Acyclic Data Transfer with Slave Initiative