Siemens SIMATIC ET 200S Operating Instructions Manual page 157

Power buses (P1/ P2)
Two internal buses (P1 and P2) that supply the electronic modules with voltage. The power
buses are fed by the power module and connected by means of the terminal modules.
Power modules
Power modules monitor the supply voltage for all the electronic modules in the potential
group. The supply voltage is fed in by means of the TM-P terminal module.
Prewiring
The wiring of the terminal modules before the electronic modules are inserted.
Process image
The process image is a component of the system memory of the DP master. The signal
states of the input modules are transferred to the process-image input area at the beginning
of the cyclic program. At the end of the cyclic program, the values of the process-image
output area are transferred to the DP slave as the signal states.
PROFIBUS
PROcess FIeld BUS, German process field bus standard specified in IEC 61784-1:2002 Ed1
CP 3/1. It defines functional, electrical, and mechanical properties for a bit-serial field bus
system.
PROFIBUS is available with the protocols DP (which stands for distributed peripherals, that
is, distributed or remote IO), FMS (which stands for field bus message specification), PA (=
process automation), or TF (= technological functions).
PROFIBUS address
Each bus node must receive a PROFIBUS address to identify it uniquely on the PROFIBUS.
The PC/programming device has the PROFIBUS address "0".
The PROFIBUS addresses 1 to 125 are permitted for the ET 200S distributed IO system.
PROFINET
Within the context of Totally Integrated Automation (TIA), PROFINET is the systematic
development of the following systems:
● PROFIBUS DP, the established field bus and
● Industrial Ethernet, the communication bus for the cell level
Experiences from both systems have been and are being integrated in PROFINET.
PROFINET as the Ethernet-based automation standard of PROFIBUS International (formerly
PROFIBUS Nutzerorganisation e.V.) defines a cross-vendor communication, automation,
and engineering model.
ET 200S
Operating Instructions, 08/2008, A5E00515771-06
Glossary
157