Rockwell Automation 1747-L40 SLC 500 Fixed Hardware Style User Manual
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Glossary
G–3
Minimum Watts — The amount of heat dissipation that can occur when
there is no field power present.
Multi–master network — A network in which more than one node has the
ability to initiate communications and initialize the link.
Network — A series of stations (nodes) connected by some type of
communication medium. A network may be made up of a single link or
multiple links.
Node — Also called a station. An address or software location on the
network.
Nominal Input Current — The current at nominal input voltage.
Off–State Current — For input circuits, the maximum amount of leakage
current allowed from an input device in its Off–state.
Off–State Leakage — For output circuits, the maximum amount of
(leakage) current that may flow when the output circuit is in its Off–state.
Off–State Voltage (max) — The maximum input voltage level detected as
an Off condition by the input module.
On–State Voltage Drop — The voltage developed across the output driver
circuit during the On state at maximum load current.
Operating Voltage — For inputs, the voltage range needed for the input to
be in the On state. For outputs, the allowable range of user–supplied voltage.
Output Device — A device, such as a pilot light or a motor starter coil, that
is energized by the programmable controller.
Points per Common — The number of input or output points connected to a
single return (common) or supply (vcc).
Protocol — The “language” or packaging of information that is transmitted
across a network.
(I/O) Rack — An I/O addressing unit that corresponds to 8 input
image–table words and 8 output image–table words. A rack can contain a
maximum of 8 I/O groups for up to 128 discrete I/O.
Remote I/O Network — A network where the communication between the
processor and the I/O is across a serial link.
Responder —A node on the DH–485 network that acts as a slave device. A
responder is not capable of initiating communications. It can only send
messages in response to a request from an initiator. The SLC 5/01 and 5/02
can also be responders.
RS–232 — An EIA standard that specifies electrical, mechanical, and
functional characteristics for serial binary communication circuits. A
single–ended serial communication interface.