Rockwell Automation 1785-Lx0C15 ControlNet PLC-5 Programmable Controllers User Manual - Manual (Page 11)

1785-UM022C-EN-P - February 2008
Preface-3
repeater two-port active physical-layer device that reconstructs and retransmits all traffic that it
hears on one ControlNet segment to another segment
Requested Packet Interval
(RPI) the maximum time allowed for the ControlNet network to update requested data. The RPI is
user-selectable on a per connection basis. For more information, see page 2-2.
scheduled maximum node
(SMAX) the maximum ControlNet node number that can transmit and receive scheduled data
scheduled transfers deterministic and repeatable transfers that are continuous and asynchronous to the ladder-
logic program scan
scheduled connection types rack connection - scheduled connection made from the PLC-5C to I/O adapters to some or
all of the discrete I/O on the adapter
module connection - scheduled connection made from the PLC-5C to I/O adapters to
individual modules
segment trunkline section of ControlNet network with terminators at each end; a segment does not
include repeaters; segments connected by repeaters make up a link
tap component that connects products to the ControlNet trunk cable; a tap is required for each
node and for each side of a repeater
terminator 75W resistor—mounted in a BNC plug—placed on each end of a ControlNet segment to
prevent reflections from occurring at the ends of the cable
trunk cable bus or central part of the ControlNet cable system
trunk-cable section length of trunk cable between any two ControlNet taps
unscheduled maximum node
(UMAX) the maximum ControlNet node number that can transmit and receive unscheduled data
unscheduled transfers non-deterministic data transfers through ladder-initiated communication or programming
devices
Term Description