User Manual

Easy to communicate between devices
7.6 PROFIBUS
Easy Book
142 Manual, 03/2014, A5E02486774-AF
Parameter
Definition
TSAP
1
and Subnet ID: ISO on TCP (RFC 1006) and S7 communication: Local and partner CPU
TSAPs in ASCII and hexadecimal formats
1
When configuring a connection with an S7-1200 CPU for ISO-on-
TCP, use only ASCII characters in the TSAP extension
for the passive communication partners.
Transport Service Access Points (TSAPs)
Using TSAPs, ISO on TCP protocol and S7 communication allows multiple connections to a
single IP address (up to 64K connections). TSAPs uniquely identify these communication
end point connections to an IP address.
In the "Address Details" section of the Connection Parameters dialog, you define the TSAPs
to be used. The TSAP of a connection in the CPU is entered in the "Local TSAP" field. The
TSAP assigned for the connection in your partner CPU is entered under the "Partner TSAP"
field.
Port Numbers
With TCP and UDP protocols, the connection parameter configuration of the Local (active)
connection CPU must specify the remote IP address and port number of the Partner
(passive) connection CPU.
In the "Address Details" section of the Connection Parameters dialog, you define the ports to
be used. The port of a connection in the CPU is entered in the "Local Port" field. The port
assigned for the connection in your partner CPU is entered under the "Partner Port" field.
7.6
PROFIBUS
A PROFIBUS system uses a bus master to poll slave devices distributed in a multi-drop
fashion on an RS485 serial bus. A PROFIBUS slave is any peripheral device (I/O
transducer, valve, motor drive, or other measuring device) which processes information and
sends its output to the master. The slave forms a passive station on the network since it
does not have bus access rights, and can only acknowledge received messages, or send
response messages to the master upon request. All PROFIBUS slaves have the same
priority, and all network communication originates from the master.
A PROFIBUS master forms an "active station" on the network. PROFIBUS DP defines two
classes of masters. A class 1 master (normally a central programmable controller (PLC) or a
PC running special software) handles the normal communication or exchange of data with
the slaves assigned to it. A class 2 master (usually a configuration device, such as a laptop
or programming console used for commissioning, maintenance, or diagnostics purposes) is
a special device primarily used for commissioning slaves and for diagnostic purposes.