Siemens Simatic CFU, Commissioning Manual, Page: 211 / 220

Prewiring
Wiring the electrics on a mounting rail before the I/O modules are connected.
Principle of frequency measurement
Frequency measurement is carried out by counting the number of pulses (only positive edges)
per period. A time measurement between two edges is not supported.
Frequency [Hz] = Number of positive edges at the digital input/Measuring window [sec]
Process image (I/O)
The CPU transfers the values from the input and output modules to this memory area. At the
start of the cyclic program, the signal states of the input modules are transmitted to the process
image input. At the end of the cyclic program, the process image output is transmitted as signal
state to the output modules.
Product version (ES) = Functional status (FS)
The product version or functional status provides information on the hardware version of the
module.
PROFIBUS
PROcess FIeld BUS, process and fieldbus standard that is specified in IEC 61158 Type 3. It
specifies functional, electrical and mechanical properties for a bit-serial fieldbus system.
PROFIBUS is available with the following protocols: DP (= Distributed Periphery), FMS (=
Fieldbus Message Specification), PA (= Process Automation) or TF (= Technological
Functions).
PROFINET
PROcess FIeld NETwork, open Industrial Ethernet Standard, which continues PROFIBUS and
Industrial Ethernet. A cross-manufacturer communication, automation and engineering model
by PROFIBUS International e.V., defined as an automation standard.
PROFINET IO controller
Device used to address connected I/O devices (e.g. distributed I/O systems). This means: The
IO controller exchanges input and output signals with assigned I/O devices. The IO controller
often corresponds to the CPU in which the automation program is running.
PROFINET IO
Communication concept for the realization of modular, distributed applications within the scope
of PROFINET.
Glossary
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