Siemens SIMATIC S7-1500 System Manual page 260

Glossary
Identification data
Information that is saved in modules, and that supports the user in reviewing the system
configuration and locating hardware changes.
Instance data block
Each call of a function block in the STEP 7 user program is assigned a data block, which is
automatically generated. Values of the input, output and in/out parameters, as well as local
block data, are stored in the instance data block.
Interface module
Module in the distributed I/O system. The interface module connects the distributed I/O
system to the CPU (IO controller) via a fieldbus, and prepares the data for and from I/O
modules.
Interrupt
The operating system of the CPU distinguishes between various priority classes that control
the execution of the user program. These priority classes include interrupts, such as
hardware interrupts. When an interrupt occurs, the operating system automatically calls an
assigned organization block. The user can program the desired reaction in the organization
block (e.g. in a FB).
Interrupt, cyclic
The CPU generates a cyclic interrupt periodically within a parameterizable time grid and then
processes the corresponding organization block.
Interrupt, hardware
A hardware interrupt is triggered by interrupt-triggering modules due to a certain event in the
process. The hardware interrupt is signaled to the CPU. The CPU then processes the
assigned organization block according to the priority of this interrupt.
Interrupt, time-delay
The time-delay interrupt is one of the program execution priority classes of SIMATIC S7. It is
generated after expiration of a timer started in the user program. The CPU then processes
the corresponding organization block.
Interrupt, time-of-day
The time-of-day interrupt is one of the program execution priority classes of SIMATIC S7.. It
is generated based on a defined date (or daily) and time (e.g. 9:50 or every hour, every
minute). The CPU then processes the corresponding organization block.
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Automation system
System Manual, 09/2016, A5E03461182-AD