Siemens Micromaster Profibus, Инструкция по эксплуатации

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PROFIBUS Optional Board Operating instructions
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PROFIBUS is an international, open field bus standard which is used widely in the
fields of production and process automation. The bus is guaranteed brand-neutral
and open by virtue of its compliance with international standards EN 50170 and
IEC 61158.
PROFIBUS-DP is a PROFIBUS communication profile optimized for high-speed,
time-critical data transmission at field level using low-cost connections.
PROFIBUS-DP is a suitable substitute for conventional, parallel 24 V signal
transmission systems in manufacturing, as well as for analog 4..20 mA signal
transmission systems in process automation.
PROFIBUS is a multi-master system, in other words, it is a bus on which several
automation, engineering or visualization systems can operate together with the
associated distributed field devices. In the context of PROFIBUS, master and slave
devices are defined as follows:
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Master devices control data traffic on the bus; they are also referred to as
"active" nodes. A master may transmit messages without prior receipt of an
external request provided that it has bus access authorization (token).
There are two classes of master:
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Class 1 master:
These are central automation stations (e.g. SIMATIC S5, S7 and
SIMADYN D) which exchange information with slaves in predefined
message cycles.
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Class 2 master:
These are programming, configuring or operator control and monitoring
systems that are used to configure or start up or monitor the plant in
operation.
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Slave devices are field devices such as drives (MICROMASTER4) , I/O
devices and valves. They never receive bus access authorization, i.e. they may
only acknowledge received messages or return information to a master on
request. Slave devices are also referred to as "passive" nodes.