Start Information For Ob 40 For The Interrupt Inputs Of The Integrated I/Os - Siemens SIMATIC S7-300 Series Reference Manual

CPUs
"Interrupt Inputs" of the CPU 314 IFM
If you want to assign interrupt functions to the digital inputs 126.0 to 126.4,
configure your CPU parameters in STEP 7 accordingly.
Note the following points:
These digital inputs have a very low signal delay. At this interrupt input, the module
recognizes pulses with a length as of approx. 10 to 50 ms. Always use shielded
cable to connect active interrupt inputs in order to avoid interrupts triggered by line
interference.
Note The minimum pulse width of an interrupt trigger pulse is 50 ms.
Start information for OB40
Table 1-10 shows the temporary (TEMP) variables of OB40 relevant for the
"Interrupt inputs" of the CPU 314 IFM. Refer to theSystem and Standard functions
reference manual for details on the process interrupt OB.
Table 1-11 Start Information for OB 40 for the Interrupt Inputs of the Integrated I/Os
Byte Variable
6/7 OB40_MDL_ADDR
8 on OB40_POINT_ADDR
1-44
Data Type
WORD B#16#7C
DWORD See Figure 1-9
PLC S7-300, CPU Specifications CPU 312 IFM to CPU 318-2 DP
Description
Address of the interrupt triggering
module (in this case, the CPU)
Signaling of the interrupt triggering
integrated inputs
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