Siemens SIMATIC S7-1500 System Manual page 221

Glossary
Parameter assignment
Parameter assignment is the transfer of parameters from the IO controller / DP master to the
IO device / DP slave.
PELV
Protective Extra Low Voltage = grounded extra low voltage with safe isolation
Pre-wiring
Wiring of the electrical system on the front connector before the front connector is used on
the I/O module.
Process image (I/O)
The CPU transfers the values from the input and output modules in this memory area. At the
start of the cyclic program the signal states of the input modules are transmitted to the
process image of the inputs. At the end of the cyclic program the process image of the
outputs is transmitted as signal state to the output modules.
PROFIBUS
PROcess FIeld BUS, process and fieldbus standard that is specified in IEC 61784-1:2010
Ed3 CP 3/1. It specifies functional, electrical and mechanical characteristics for a bit-serial
field bus system.
PROFIBUS supports the protocols DP (= Distributed I/O), FMS (= Fieldbus Message
Specification), PA (= Process Automation), or TF (= Technological Functions).
PROFIBUS master
When masters are in possession of the token, they can send data to other devices and
request data from them (= active device).
PROFINET
PROcess FIeld NETwork, open industrial Ethernet standard which further develops
PROFIBUS and industrial Ethernet. A cross-manufacturer communication, automation, and
engineering model defined by PROFIBUS International e.V. as an automation standard.
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S7-1500 Automation System
System Manual, 02/2014, A5E03461182-AB