Glossary
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PROFIBUS
Pro
cess
Fi
eld
Bus
is an open Fieldbus system used to network
PROFIBUS compatible devices. PROFIBUS works with three
different protocols: PROFIBUS-DP (Decentral Peripheral),
PROFIBUS-FMS (Fieldbus Message Specification), and
PROFIBUS-PA (Process Automation). PROFIBUS is standard-
ized in EN 50 170.
Protocol
A set of rules and regulations which control the flow of informa-
tion in a communication system. The term protocol can refer to
either hardware or software.
Receive
The Fieldbus device receives a telegram from the DP master
through the SPI 3.
Receive channel
Data channel for data which the SPI 3 receives.
Remote peripheral
I/O device which is not directly integrated in the PLC CPU, but
is accessed remotely via the bus.
Response monitoring
If a slave is not accessed within the response monitoring time-
out, it switches automatically to a safe status by setting all out-
puts to 0. The response monitoring timeout is specified during
parameter setting.
Response timeout
The duration of time within which the partner device must re-
spond. The response timeout must be configured the same for
both partner devices.
Segment
Section of the bus cable between two terminating resistors. A
bus segment can support up to 32 bus stations, and several bus
segments can be connected together with RS 485 repeaters.
Send
The DP master sends a telegram to a Fieldbus device through
the SPI 3.
Send channel
Data channel for data which is sent to the SPI 3.
Slave
Bus station which is only allowed to exchange data with a mas-
ter, and only on request of the master.
