Siemens SIMATIC S5 Manual page 63

IP 265
6 Control of the IP 265 by the
CPU User Program
6.1 Control of IP 265 Program Execution
Program execution in the IP 265 is controlled by the CPU user program. The IP 265-related part of
the CPU user program communicates with the IP 265 via the PIQ and PII of the CPU:
• In the process image of the outputs (PIQ), the CPU user program stores commands (control
word) intended for the controller of the IP 265.
• In the process image of the inputs (PII), the CPU user program reads out the status of the
IP 265 (status word).
• In normal operation of the IP 265, parameters can be exchanged between the CPU user
program and the IP 265 user program via the PII and the PIQ for the following purposes:
- Transfer of the results of logic operations from the CPU to the IP 265 and vice versa (results
of logical operations in the user program)
- Loading time values and counts of the CPU into the IP 265
- Reading counts from the IP 265 into the CPU
Note
The transfer of the parameters requires additional program capacity of the IP 265.
The CPU user program may only write input parameters into the PIQ if the IP 265 is not controlled
by COM 265 and is therefore "enabled" for communication with the CPU. This state is indicated by
the control bit in the status word ( Section 4.3.2).
To ensure correct IP 265 program scanning, the following note is of particular importance for control
of the IP 265 by the CPU user program:
Note
Before every transfer of new input parameters to the IP 265, the status word of the
IP 265 must be evaluated in the CPU user program.
The representation in Figure 6-1 shows the control of the IP 265 by the CPU user program. Normal
operation is represented, i.e. a memory submodule with tested IP 265 user program is plugged into
the IP 265.
EWA 4NEB 812 6130-02a
Control of the IP 265 by the CPU User Program
6-1