Flowserve MX/QX Profibus DP/PA Field Unit - Manual (Page 86)

PB DPV1 / PA Field Unit Installation and Maintenance FCD LMENIM2336-03 – 12/12
86
PROFIBUS is a data communication network which interconnects PROFIBUS-compatible automa-
tion systems and field devices on the cell and field levels of an automation environment. PROFIBUS
networks can use the communications protocols “DP” (Decentralized Periphery), “FMS” (Fieldbus
Message Specification – not supported by the MX/QX device), and “PA” (Process Automation).
QX QX Flowserve Limitorque abbreviation for Quarter-turn Electronic Actuator.
Repeater An electronic device that allows the RS-485 (PROFIBUS) copper wire transmission media
to be extended over larger distances.
RS-485 An EIA standard for half duplex, serial data transmission use in multipoint, or parallel,
communication systems.
Serial Data Transmission The transmission of digital data bits sequentially over a transmission
medium. Compare to parallel data transmission.
Segment A section of the PROFIBUS network that has stations attached. There are limitations to
the length of the segments based on baud rate and station loading.
Segment Coupler A device that is used to attach PA devices to a PROFIBUS network.
Slave The MX/QX PB is a passive slave device. It receives commands from the master and sends
process data and diagnostic information to the master when requested by the master.
Termination The ends of each copper segment of PROFIBUS must be terminated, that is, placing a
termination resistor between the two conductors that match the characteristic impedance of the wire
to dissipate the signal and prevent reflections.
Token A bit pattern that is passed between active stations that gives that station (such as a
PROFIBUS master) the explicit right to access the network. In the case of a PROFIBUS master, the
station will service its set of slaves.
Topology The physical description of the arrangement of stations on a network. Topologies include
point-to-point, bus, tree, and ring.
Transducer Block A software block that controls access to the I/O devices through a device-inde-
pendent interface defined for use by function blocks.
Twisted Pair A serial, digital data communications medium incorporating two wires twisted
together to minimize interference from nearby noise sources.