Technical data

10.1 Basics of Data Transmission with Cyclic I/Os (ZP)
When you have specified a SIMATIC S5 PLC with a CP 5430 TF as being
an active station, you can program data transmission with "cyclic I/Os" for
this PLC and exchange (poll) data with PROFIBUS-compatible field devices.
The communication between the SIMATIC S5 PLC and field device
functions according to the master slave method.
This section describes the functions of the cyclic I/Os from the point of view
of the CPU control program
In data transmission with cyclic I/Os the data exchange takes place via the
I/Os of the SIMATIC PLC, as follows
Communication using cyclic I/Os is only permitted using the base interface
number (base SSNR).
➣ The data for transmission are assigned to the output area of the I/Os in
the control program.
➣ The received data are stored in the input area of the I/Os.
➣ Transmitted and received data can be processed with STEP 5
operations.
–
Data for transmission via the output area
–
Received data via the input area
All I/O bytes via which you want to transmit and all I/O bytes via which you
want to receive must be designated as cyclic I/Os. To do this, you program
I/O areas using COM 5430 TF (refer to section 10.2).
B8976060/02 Communication with Cyclic I/Os
10 - 3 Volume 1