Siemens S7-300 appendix Interrupts, Interrupt inputs, Start information for OB40

Technical data of CPU 31xC 6.6 Technical data of the integrated I/O

6.6.4Interrupts

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

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.

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 System and Standard Functions.

Table 6-11 Start information for OB40, relating to the interrupt inputs of the integrated I/O

Byte	Variables	Data type		Description
6/7	OB40_MDL_ADDR	WORD	B#16#7C	Address of the interrupt-
				triggering module (here: default
				addresses of the digital inputs)
8 on	OB40_POINT_ADDR	DWORD	see the figure	Displaying the interrupt-
			below	triggering integrated inputs

CPU 31xC and CPU 31x, Technical data	6-45
Manual, Edition 08/2004, A5E00105475-05