Siemens SINEC L2 User Manual

System Description S5-95U, SINEC L2
Target Rotation Time
A token cycle takes a certain amount of time. You must set the maximum permissible token cycle
time as target rotation time (target rotation time in DB1, TRT parameter).
Even the transmission of large amounts of data must conform to the target rotation time set in DB1.
In order to conform to this time, the SINEC L2 uses the following principle.
Time Management of the Network
Each active station measures the time in which it was not in the possession of the token. This time
is the station’s “real” rotation time, i.e., the time used up by the other stations. The station
compares this measured time with the previously set target rotation time.
The processing of the frame to be transmitted depends on the results of this comparison and on the
priority of the message frames as follows:
The preset priority of the message frames is low for the standard connection ( chapter 4), PLC-to-
PLC connection ( chapter 6) and cyclic I/O ( chapter 7). Only for layer 2 access can you decide
whether the message frame is to be given high or low priority.
Possible results of the comparison between the rotation time measured (the "real" rotation time)
and the target rotation time:
1) The "real" rotation time is shorter than the target rotation time.
Result: All send and receive jobs in the queue are executed until the target rotation time has
been reached or the jobs in the queue have been processed; first the message frames
with high priority, then the message frames with low priority.
2) The "real" rotation time is longer than the target rotation time.
Result: Only one more message frame with high priority is transmitted. The message frames
with low priority are not transmitted until the "real" rotation time is shorter than the
target rotation time in the following token cycles.
This is shown in Figures 1-4 and 1-5.
1-6 EWA 4NEB 812 6112-02

Siemens SINEC L2 Specifications

General

Power Supply	24 V DC
Operating Temperature	-40 to +70 °C
Product Family	SINEC
Protection Class	IP30
Product Type	Switch
Dimensions	Varies depending on the specific model
Network Standards	IEEE 802.3, IEEE 802.1Q, IEEE 802.1p

Summary

1 System Description

1.2 The SINEC L2 Local Area Network

1.3 Procedure for Accessing the SINEC L2 Network

1.4 Assigning Parameters for the L2 Interface of the S5-95U

Details parameter assignment in DB1 for the L2 interface, including basic parameters and data transmission parameters.

2 Installation Guidelines

2.1 Basic Configuration

Illustrates main components of SINEC L2 in RS 485 and S5-95U installation technology.

2.2 Installing a SINEC L2 Bus Segment

Explains how to install a SINEC L2 bus segment, including mounting the bus cable on the connector.

2.3 Linking Bus Segments with the L2 Repeater

3 Start-Up, Tests, and Diagnostics

3.2 START-UP Sequence

Details the sequence of operations during startup, including power recovery and cold restart routines.

3.3 Starting Up a System

Provides safety suggestions, minimum hardware requirements, and startup diagnostics procedures.

3.4 FMA Services

4 Data Transmission Using a Standard Connection

4.2 Assigning Parameters in DB1 of the S5-95U for Data Exchange with Standard Connections

Details parameter assignment in DB1 for standard connections, including mailbox and coordination byte locations.

4.5 Programming Example for Data Transmission via a Standard Connection

5 Integral Standard Function Blocks L2-SEND and L2-RECEIVE

5.1 Parameters for L2-SEND and L2-RECEIVE

Lists and explains parameters for L2-SEND/L2-RECEIVE, including job number allocation and data source/destination.

5.2 Direct and Indirect Parameter Settings for the L2 Function Blocks

6 Data Transmission Using PLC-to-PLC Connections

6.2 Assigning Parameters in DB1 of the S5-95U for Data Exchange with PLC-to-PLC Connections

Details parameter assignment in DB1 for PLC-to-PLC connections, including station identification and status byte locations.

6.3 Programming Example for Data Transmission via PLC-to-PLC Connections Using Standard Function Blocks

7 Data Transmission Using Cyclic I/O

7.2 Assigning Parameters in DB1 of the S5-95U for Data Exchange with Cyclic I/O

Covers parameter assignment in DB1 for cyclic I/O, including ZP areas, status bytes, and ZP master/slave connection.

7.4 Programming Example for Data Transmission via Cyclic I/O

8 Data Transmission by Accessing Layer 2 Services

8.3 Assigning the S5-95U Parameters for Data Communications

Details parameter assignment in DB1 for layer 2 accesses, including status byte locations and job number definitions.

8.4 FBs for Managing All Layer 2 Services

9 Programmer Functions Over the SINEC L2 Network

9.2 Selecting the L2 Interface

Guides on selecting the SINEC L2 interface using the programmer's 'INTERFACE SELECTION' function.

9.3 Entering Defaults

9.4 Editing a Path

Details how to edit a path to reach a station on the SINEC L2 LAN using the 'BUS DIALLING' utility.

9.5 Setting the L2 Basic Parameters on the Programmer

Describes how to set L2 basic parameters on the programmer via the 'SYSID CP L2 (LOCAL)' screen.

9.6 Activating an Edited Path