Siemens CPU 317-2 PN/DP - Point-To-Point Connection; Data Consistency

Communication
3.2 Communication services
CPU 31xC and CPU 31x, Technical Data
Manual, 01/2006 Edition, A5E00105475-06
3-15
Reference
Further information
• on configuring in STEP 7 is found in the
Configuring Hardware and Connections in
STEP 7
manual
• of a basic nature is contained in the
Communication with SIMATIC Manual.
• about the TeleService adapter is available under article ID 20983182 on the Internet URL
http://support.automation.siemens.com.
• on SFCs, refer to
Instruction list .
For further information refer to
STEP 7 Online Help or System and Standard Functions
reference manual.
• on communication are found in the
Communication with SIMATIC Manual.
3.2.8 Point-to-point connection
Properties
PtP communication enables you to exchange data via serial port. PtP communication can be
used to interconnect automation devices, computers or communication-capable systems of
external suppliers. The function also allows adaptation to the protocol of the communication
partner.
Reference
Further Information
• on SFCs are found in the
Instruction list .
For detailed information, refer to the
STEP 7 Online Help , or to the System and Standard
Functions
Reference Manual.
• on communication are found in the
Communication with SIMATIC Manual.
3.2.9 Data consistency
Properties
A data area is consistent if it can be read or written to from the operating system as a
consistent block. Data exchanged collectively between the stations should belong together
and originate from a single processing cycle, that is, be consistent. If the user program
contains a programmed communication function, for example, access to shared data with X-
SEND/ XRCV, access to that data area can be coordinated by means of the "BUSY"
parameter itself.