Siemens SIMATIC S7-1500 System Manual page 292

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.
Interrupt
The operating system of the CPU distinguishes between various priority classes that control
the execution of the user program. These priority classes include, for example, 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, for
example in an 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.
Interrupt, update
When it receives an update interrupt, the operating system calls the update interrupt OB.
This may happen if you changed a parameter on a slot of a device.
SIMATIC Drive Controller
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