Siemens Simatic S7-1500 Function Manual page 74

Firmware of the CPU
In SIMATIC, a distinction is made between the firmware of the CPU and user programs.
The firmware is a software embedded in electronic devices, which means it is permanently
connected with the hardware functionally. It is usually saved in a flash memory, such as
EPROM, EEPROM or ROM, and cannot be replaced by the user or only with special means
or functions.
User program: see glossary entry "User program"
H-Sync Forwarding
H-Sync Forwarding enables a PROFINET device with MRP to forward synchronization data
(synchronization frames) only within the PROFINET ring.
Through H-Sync Forwarding, the synchronization data is also forwarded during
reconfiguration of the PROFINET ring. This reduces the cycle time utilization.
H-Sync Forwarding is recommended for PROFINET devices that you use in the PROFINET
ring of redundant S7-1500R systems.
H-Sync Forwarding is not relevant for redundant S7-1500H systems.
I/O module
Device of the distributed I/O that is used as interface between the controller and the process.
Interrupt
The CPU's operating system 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 required response is programmed 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, diagnostics
Diagnostics-capable modules signal detected system errors to the CPU using diagnostic
interrupts.
Interrupt, hardware
A hardware interrupt is triggered by interrupt-triggering modules due to a certain event in the
process. The hardware interrupt is reported to the CPU. The CPU then processes the
assigned organization block according to the priority of this interrupt.
Cycle and response times
Function Manual, 10/2018, A5E03461504-AD
Glossary
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