Siemens Simatic S7-400 - Manual (Page 614)

Glossary
Glossary-8
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
Ground, to
To ground means to connect an electrically conductive part via a grounding
system to the grounding electrode (one or more conductive parts having a very
good contact to ground).
Hardware interrupt
A hardware interrupt is triggered by interrupt-triggering modules in response to a
particular event in the process (limit value violation; the module has completed
the cyclic change of its channels).
The hardware interrupt is reported to the CPU. In accordance with the priority of
this interrupt, the
³
organization block assigned to it is processed.
Input delay
Parameter in STEP 7 for digital input modules. The input delay is used to
suppress injected interference. Interfering pulses from 0 ms to the set input delay
are suppressed.
The set input delay is subject to a tolerance that can be obtained from the
technical specifications of the module. A high input delay suppresses long
interfering pulses, whereas a low input delay suppresses short ones.
The permissible input delay depends on the length of the cable between the
encoder and the module. For example, a high input delay has to be set for long
unshielded supply conductors to the encoder (longer than 100m).
Integration time
The integration time is the inverse value of the ³ interference frequency
suppression in ms.
Interface, multipoint
³ MPI
Interference frequency suppression
Parameter in STEP 7 for analog input modules. The frequency of the AC network
can interfere with the measured value, especially with measurements in low
voltage ranges and with thermocouples. This parameter is used by the user to
specify the prevailing line frequency on his system.
Interrupt
The SIMATIC S7 is familiar with 28 different run-time level, which govern running
of the user program. These run-time levels include interrupts such as hardware
interrupts, among other things. When an interrupt occurs, the operating system
automatically calls an assigned organization block in which the user can program
the reaction he wants (for example, in an FB).