Спецификация протокола Profibus

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and is decremented every bit time after each transmission of a frame. This

frame transmission is indicated by a Ph-DATA confirm primitive after transfer of

a Ph-DATA request primitive (class: END-OF-DATA-AND-ACTIVITY). If the timer

expires before a frame has been received, as indicated by a Ph-DATA indication

primitive (class: START-OF-ACTIVITY), an error has occurred. As a result of that

a retry or a new message cycle is initiated.

Time-out Timer: This timer serves to monitor the bus activity at master and

slave stations. After transfer of a Ph-DATA request primitive (class: END-OF-

DATA-AND-ACTIVITY) and return of a Ph-DATA confirm primitive or after receiving

a Ph-DATA indication primitive (class: END-OF-ACTIVITY or END-OF-DATA-AND-

ACTIVITY), the timer is loaded with a multiple of the Slot Time (cf subclause

9.1.7 of this part) and is decremented every bit time as long as no Ph-DATA

indication primitive (class: START-OF-ACTIVITY) has been received. If the timer

expires, a fatal error has occurred, which for the master station causes a

(re)initialization. The FMA1/2 User of the slave or master station respectively

receives a time-out notification (cf subclause 5.2.3.3 of Part 3).

Syn Interval Timer: Master and slave stations use this timer to monitor the

transmission medium for „permanent transmitters“. After every Ph-DATA indication

primitive (class: START-OF-ACTIVITY) the timer is loaded with the value T

SYNI

(cf subclause 9.1.7 of this part) and decremented every bit time, as long as no

Ph-DATA indication primitive (class: END-OF-ACTIVITY or END-OF-DATA-AND-

ACTIVITY) has been received. If the timer expires, an error of the transmission

medium has occurred. The FMA1/2 User receives a corresponding notification

(cf subclause 5.2.3.3 of Part 3).

GAP Update Timer: This timer operates in the same way as described in subclause

4.4 of Part 4.

The specifications stipulated in subclause 4.4 of Part 4 shall apply for the

optional counters.

8.5 Frame Structure

Each FDL frame (FDL PDU) consists of a Start Delimiter Data Link, an Information

Field and a Cyclic Redundancy Check (CRC). The Information Field is divided into

an Address Field and a Control Field. Additionally, a Data Field may exist. The

Information Field is Null in the Short-Acknowledgment.

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SDF DA/SA

FC DATA_UNIT CRC

Information Field Length = L

FDL Telegram

1,4 0,2 0,1 0 bis 246 2 Octets

Notation herein:

SDF

Start Delimiter Data Link, Length 1 or 4 octets

DA Destination Address - Information Field

SA Source Address - Information Field

FC Frame Control - Information Field

DATA_UNIT Data Field, Length (L-3), maximum 246 octets

CRC Cyclic Redundancy Check, Length 2 octets

Figure 6: FDL frame format

8.5.1 Frame Character

The Start Delimiter Data Link, the Information Field and the CRC consist of a

number of octets of 8 bit each. Each FDL octet is structured as follows:

b2 b3 b4 b5 b6 b7

MSB LSB

12 3 4 56 7 8

Transmitted

Bit Sequence

Information

sig. Bit

Figure 7: Octet Structure (cf Fig. 9 of Part 4, subclause 4.5.1)

8.6 Frame Formats

Based on the specifications of subclause 4.6 of Part 4 and its subclauses the

different frame formats are described according to the frame format explained in

subclause 9.5 of this part.

The figures contained in the following clauses do not show any sequences

(request --> acknowledgment or response) but frame formats of the same category

(Hd = 4; fixed length with/without data field and variable length), i.e. request

frames may be followed by different acknowledgment or response frames

(cf subclause 8.9 of this part).

The Start Delimiter Data Link may not be confused with the Start Delimiter SD

of the Physical Layer.

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8.6.1 Frames of fixed Length with no Data Field

SDL1 Information Field CRC

A)Request Frame

SDL1 Information Field CRC

B)Acknowledgement Frame

C)Short Acknowledgement Frame

SDL5 CRC

Notation herein:

SDL1 Start octet 1 (Start Delimiter 1 Data Link), Code: 10H

SDL5 Start octet 5 (Start Delimiter 5 Data Link), Code: E5H

CRC Cyclic Redundancy Check, 2 octets

L Information Field Length, fixed number of octets: L = 3

Information Field cf Part 4, subclause 4.6.1

Figure 8: Frames of fixed Length with no Data Field (cf Fig. 10 of Part 4)

Transmission Rules

Beside the transmission rules of the Ph Layer stipulated in IEC 1158-2,

clause 9, the receiver shall check the DA/SA- and CRC octets for each frame. If

the check produces a negative result the whole frame shall be discarded.

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9.6.2 Frames of fixed Length with Data Field

A)Send/Request Frame

B)Response Frame

SDL3 Information Field CRC

Notation herein:

SDL3 Start Delimiter 3 Data Link, Code: A2H

CRC Cyclic Redundancy Check, 2 octets

L Information Field Length, fixed number of octets: L = 11

Information Field cf Part 4, subclause 4.6.2

Figure 9: Frames of fixed Length with Data Field (cf Fig. 11 of Part 4)

Transmission Rules

The same transmission rules shall apply as for frames of fixed length with no

Data Field (cf subclause 9.6.1 of this part)

8.6.3 Frames with variable Data Field Length

A)Send/Request Frame

B)Response Frame

SDL2 Information Field CRC

LE LEr

SDL2

SDL2 CRC

LE LEr

SDL2 Information Field

Notation herein:

SDL2 Start Delimiter 2 Data Link, Code: 68H

LE Length, Value: 4 to 249

LEr Length (repeated)

CRC Cyclic Redundancy Check, 2 octets

L Information Field Length, variable number of octets: L = 4 to 249

Information Field cf Part 4, subclause 4.6.3

Figure 10: Frames with variable Data Field Length (cf Fig. 12 of part 4)

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Transmission Rules

The same transmission rules as for frames of fixed length with no data field

shall apply (cf subclause 9.6.1 of this part). In addition, the receiver shall

verify if LE and Ler coincide. The information octets shall be counted from the

Destination Address (DA) up to the Cycling Redundancy Check and shall be

compared with LE.

8.7 Token Frame

SDL4 DA CRCSA

Notation herein:

SDL4 Start Delimiter 4 Data Link, Code: DCH

DA Destination Address

SA Source Address

CRC Cyclic Redundancy Check, 2 octets

Figure 11: Token Frame (cf Fig. 13 of Part 4)

Transmission Rules

The same transmission rules as for frames of fixed length with no data shall

apply (cf subclause 9.6.1 of this part).

8.8 Length, Address, Control and Check Octet

8.8.1 Length Octet (LE)

The length octet described in subclause 4.7.1 of Part 4 shall apply.

8.8.2 Address Octet (DA/SA)

The address octet described in subclause 4.7.2 of Part 4 shall apply.

8.8.2.1 Link Service Access Point (LSAP)

The Link Service Access Point (LSAP) described in subclause 4.7.2.2 of Part 4

shall apply.

8.8.3 Control Octet (FC)

The control octet described in subclause 4.7.3 of Part 4 shall apply.

8.8.4 Check Octet (FCS)

In contrast to PROFIBUS Specification "Medium Access Methods" and "Transmission

Protocol" a Cyclic Redundancy Check (CRC) is stipulated for the frames to be

transmitted. The CRC is realized by calculating and appending a check field of

16 bit (2 octets). The calculation and analysis of the check field is realized

as follows:

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on the transmitting side

the message to be transmitted (without CRC), the polynomial necessary for

calculating the CRC and the composite message (including CRC) shall be

considered as vectors M(X), F(X) and D(X) of dimensions k, n-k and n

respectively.

The message vector M(X) shall be defined to be

M(X) = m

k-1

+ m

k-2

+ ... + m

k-1

+ m

(22)

and the check field F(X) shall be defined to be:

F(X) = f

n-k-1

+ ... + f

(23)

= f

+ ... + f

The composite vector D(X) for the complete message shall be constructed

from the message and the CRC vector and shall be defined to be:

D(X) = M(X)X

n-k

+ F(X) (24)

= m

n-1

n-2

+ ... +m

n-k

n-k-1

+ ... +f

= m

n-1

+ m

n-2

+ ... + m

+ ... +f

The check field is the remainder upon division of F(X) by the generator

polynomial G(X). The remainder is calculated as follows:

F(X) = L(X)(X

+1) + M(X)X

n-k

(mod G(X)) (25)

where G(X) is the generator polynomial defined as:

G(X) = X

n-k

+ g

n-k-1

+ ... + 1 (26)

= X

+ X

+ X + 1

and L(X) is the maximal weight polynomial (all 1s) defined as:

L(X) =

−

= X

n-k-1

+ X

n-k-2

+ ... + X + 1 (27)

= X

+ X

+ ... + X

+ X + 1

The Cyclic Redundancy Check defined by means of the generator polynomial

G(X) enables a Hamming Distance Hd = 4 for message lengths shorter than

344 octets and Hd = 5 for lengths shorter than 15 octets.

on the receiver side:

The received message consists of an octet sequence that is composed of the

actual message and the check field. It shall be considered as a vector

V(X) of dimension u :

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V(X) = v

u-1

+ v

u-2

+ ... + v

u-1

X + v

(28)

The remainder R(X) of V(X) is computed in the same way as for the

transmission side:

R(X) = L(X)X

+ V(X)X

n-k

(mod G(X)) (29)

= r

n-k-1

+ ... + r

If no error has occurred during message transmission, R(X) is equal to a

constant remainder polynomial given by:

(X) = L(X)X

n-k

(mod G(X)) (30)

= X

+ X

The initial value of the remainder that has to be computed at the receiver

side shall be the hexadecimal value 0FFFF.

8.8.5 Data Field (DATA_UNIT)

The data field described in subclause 4.7.5 of Part 4 shall apply.

8.9 Transmission Procedures

The transmission procedures described in subclause 4.8 of Part 4 shall apply.

9 PROFIBUS Layer 2 Interface

9.1 FDL User - FDL Interface

The FDL User - FDL Interface described in subclause 4.1 of Part 3 shall apply.

9.2 FMA1/2 User - FMA1/2 Interface

The FMA1/2 User - FMA1/2 Interface described in subclause 4.2 of Part 3 shall

apply.

10 Management (FMA1/2)

10.1 General Description of FMA1/2 Functions

The general description of FMA1/2 functions described in subclause 5.1 of Part 3

shall apply.

10.2 FDL - FMA1/2 Interface

The FDL - FMA1/2 Interface described in subclause 5.2 of Part 3 shall apply.

10.2.1 Overview of Services

The services described in subclause 5.2.1 of Part 3 shall apply.

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10.2.2 Overview of Interactions

The interactions described in subclause 5.2.2 of Part 3 shall apply.

10.2.3 Detailed Specification of Services and Interactions

The specification of services and interactions described in subclause 5.2.3 of

Part 3 shall apply.

10.2.3.1 Reset FDL

The service described in subclause 5.2.3.1 of Part 3 Reset FDL shall apply.

10.2.3.2 Set Value FDL, Read Value FDL

Due to the integration of IEC 1158-2, the specifications of the services Set

Value FDL and Read Value FDL, which are defined in the subclause 5.2.3.2 of Part

3, shall be extended with the following associated baud rate parameter

(cf tables 28 and 29 of Part 3):

- Baud_rate: 31.25 kbit/s

10.2.3.3 Fault FDL

The specifications of the service Fault FDL defined in subclause 5.2.3.3 of Part

3 shall apply.

10.3 PhL - FMA1/2 Interface

The interface described in subclause 5.3 of Part 3 shall apply to describe the

interface between PhL and FMA1/2.

10.3.1 Overview of Services

The Ph Layer, as described in IEC 1158-2, clause 6, provides the following

services to FAM1/2

- Reset PhL

- Set Value PhL

- Get Value PhL

- Event PhL

The services shall have the same meaning as described in subclause 5.3.1 of

Part 3. The Read Value PHY corresponds to the Get Value PhL.

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10.3.2 Overview of Interactions

The following service primitives shall apply at the PhL - FMA1/2 Interface:

Service Primitive permissible for the following

users

Reset PhL Ph-RESET request Master and Slave

Set Value PhL Ph-SETVALUE request Master and Slave

Ph-SETVALUE confirm Master and Slave

Get Value PhL Ph-GETVALUE request Master and Slave

Ph-GETVALUE confirm Master and Slave

Event PhL Ph-EVENT indication Master and Slave

Temporal Relationships of Service Primitives:

Master/Slave

Station 1

Master/Slave

Station n

FMA1/2 PhL

Ph-RESET req

Figure 12: Reset - PhL - Service

Master/Slave

Station 1

Master/Slave

Station n

FMA1/2 PhL

Ph-xxxxx req

Ph-xxxxx con

Figure 13: Set Value and Get Value PhL Service (cf Fig. 14 of Part 3)

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Master/Slave

Station 1

Master/Slave

Station n

FMA1/2 PhL

Ph-EVENT ind

Figure 14: Event PhL Service (cf Fig. 15 of Part 3)

10.3.3 Detailed Specification of Services and Interactions

10.3.3.1 Reset PhL

The service Reset PhL is

mandatory

The Ph-RESET request primitive is given to the PhL by the FMA1/2 to reset PhL.

The PhL executes this service as described in IEC 1158-2, clause 6. It shall be

noted that in contrast to PROFIBUS Management (FMA1/2), no confirmation is

returned by PhL (i.e. the FMA1/2 shall generate a confirmation for the FMA1/2-

User).

Parameters of the Primitives:

Ph-RESET request

- This primitive has no parameters.

10.3.3.2 Set Value PhL, Get Value PhL

Set Value PhL

The service Set Value PhL is

optional

The FMA1/2 passes a Ph-SETVALUE request primitive to a PhL to set a specified

variable to a desired value. The PhL will select the variable after receiving

the primitives and set it to this value. The FMA1/2 receives a confirmation

about this in a Ph-SETVALUE confirm primitive.

Parameters of the Primitives

Ph-SETVALUE request

(parameter name, new value)

- The parameter, parameter name, specifies the variables.

- The parameter, new value, specifies the new value of the variable (cf IEC

1158-2, clause 6):