Siemens simatic c7-621 Hardware Installation Manual page 127

FM An FM (function module) is a module that relieves the CPU of the S7-300
and S7-400 programmable controllers of time-critical or memory-intensive
process signal handling tasks. FMs generally use the internal bus for
high-speed data exchange with the CPU. Examples of FM applications
include counting, positioning, closed-loop control.
Functional Ground Grounding to ensure the intended purpose of the electrical devices.
Functional grounding has the effect of short-circuiting interference voltages
that would otherwise have unacceptable effects on the devices.
Ground
Conductive ground whose electrical potential at every point can be taken as
zero.
In the area of grounding electrodes, ground can have a potential different to
zero. This is frequently referred to as "reference ground".
Grounding
To connect an electrically conductive part with the grounding electrode (one
or more conductive parts that have very good contact to ground) via a
grounding point.
H
Hardware Interrupt
A hardware interrupt is triggered by interrupt-triggering modules as the result
of certain events in the process. The hardware interrupt is signaled to the C7
CPU. Depending on the priority of the interrupt, the corresponding
organization block is then executed.
I
Information
The STEP 7 info functions allow you to display status information on the
Function
programming device via the connected C7 during the different phases of
startup and during operation of a programmable controller.
Interface, –> MPI
Multipoint
Interrupt The –> operating system of the C7 CPU recognizes 10 different priority
classes that control execution of the user program. Interrupts such as
hardware interrupts belong to these priority classes. When an interrupt
occurs, the operating system automatically calls an assigned organization
block in which the user can program the desired response (for example, in an
FB).
C7-621 / C7-621 AS-i Control Systems
C79000-G7076-C621-01
Glossary
Glossary-5