Interrupts - Siemens Simatic S7-300 Technical Data Manual

6.6.4

Interrupts

Interrupt inputs
All digital inputs of the on-board I/O of CPUs 31xC can be used as interrupt inputs.
You can specify interrupt behavior for each individual input in your parameter declaration.
Options are:
• no interrupt
• Interrupt at the positive edge
• Interrupt at the negative edge
• Interrupt at the positive and negative edge
Start information for OB40
The table below shows the relevant temporary variables (TEMP) of OB40 for the interrupt
inputs of 31xC CPUs. A description of process interrupt OB 40 is found in the Reference
Manual
Table 6-11
Byte
6/7
8 on
CPU 31xC and CPU 31x, Technical data
Manual, Edition 08/2004, A5E00105475-05
Note
Every channel will hold one event if the rate of incoming interrupts exceeds the handling
capacity of OB40. Further events (interrupts) will be lost, without diagnostics or explicit
message.
System and Standard Functions
Start information for OB40, relating to the interrupt inputs of the integrated I/O
Variables
OB40_MDL_ADDR
OB40_POINT_ADDR
6.6 Technical data of the integrated I/O
.
Data type
WORD B#16#7C
DWORD see the figure
below
Technical data of CPU 31xC
Description
Address of the interrupt-
triggering module (here: default
addresses of the digital inputs)
Displaying the interrupt-
triggering integrated inputs
6-45