Interrupts Of The Digital Modules - Siemens SIMATIC S7-400 Reference Manual

4.5

Interrupts of the digital modules

Introduction
This section describes the interrupt behavior of the digital modules. There are two types of
interrupt:
● Diagnostic interrupt
● Hardware interrupt
Note that not all digital modules have interrupt capability or they are only capable of a subset
of the interrupts described here. For information on the digital modules that support interrupts,
refer to their specifications.
For detailed information on the OBs and SFCs mentioned below, refer to the
Help .
Enabling interrupts
The interrupts are not preset - in other words, they are inhibited without appropriate parameter
assignment. Interrupts are enabled in
Special feature: The module is inserted in ER-1/ER-2
Note
If you use the digital module in ER-1/ER-2, you must set the parameters for enabling all the
interrupts to "No" because the interrupt lines are not available in ER-1/ER-2.
Diagnostic interrupt
When diagnostic interrupts are enabled, incoming error events (initial occurrence) and
outgoing error events (error is cleared) are reported by means of an interrupt.
The CPU interrupts user program execution, and executes diagnostic interrupt OB82.
In the user program, you can call SFC 51 or SFC 59 in OB 82 to obtain more detailed diagnostic
information from the module.
The diagnostic information is consistent until such time as OB 82 is exited. When OB 82 is
exited, the diagnostic interrupt is acknowledged on the module.
Hardware interrupt
A digital input module can trigger a hardware interrupt for each channel at a rising or falling
edge, or both, of a signal status change.
You perform parameter assignment for each channel separately. The parameters can be
changed at any time (in RUN mode in the user program.)
S7-400 Automation System Module Data
Reference Manual, Ausgabe 11/2016, A5E00850736-08
4.5 Interrupts of the digital modules
STEP 7 .
Digital modules
STEP 7 Online
93