Rockwell Automation 1771ACN/B_1771ACNR/B,D17716.5.123 U.MNL CONTROLNET ADAPTER - Manual (Page 5)

Using This Manual P–3
Publication 1771-6.5.123 – May 1996
Use this term To describe
repeater two-port active physical-layer device that reconstructs and retransmits all traffic it
hears on one segment to another segment
remote I/O link a serial link for carrying I/O data between a PLC or SLC processor/scanner and
remote I/O adapters
RS-232-C port a serial port that complies with accepted industry standard for serial binary
communication circuits in a point-to-point link
scheduled transfers deterministic and repeatable transfers that are continuous and asynchronous to the
ladder-logic program scan
segment trunk-cable sections connected via taps with terminators at each end;
a segment does not include repeaters
serial port a port that transmits/receives data and control bits sequentially over a single
transmission line (see RS-232-C port)
standard–density i/o module a module that provides up to 8 input terminals or 8 output terminals
tap a component that connects products to the ControlNet trunk cable. A tap is required
for each node and for both sides of each repeater.
terminator a 75-ohm resistor (mounted in a BNC plug) placed on the ends of segments to prevent
reflections from occurring at the ends of cables.
trunk cable bus or central part of a cable system.
trunk-cable section length of trunk cable between any two taps
two–slot addressing a method of addressing where the processor can address its I/O in 2–slot I/O groups
unscheduled transfers non-deterministic data transfers through ladder-initiated communication or
programming devices
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