Rockwell Automation 1747-L40 SLC 500 Fixed Hardware Style - Manual (Page 213)

Glossary
G–4
RTB —Removable Terminal Block.
Signal Delay — For inputs, the response time required to transmit the circuit
status from the field wiring to the digital logic. For outputs, the time
required to transmit the circuit status from digital logic to the output wiring.
Sinking — A term used to describe current flow between an I/O device and
SLC I/O circuit — typically, a sinking device or circuit provides a path to
ground, low, or negative side of power supply.
Sinking/Sourcing — Describes a current signal flow relationship between
field input and output devices in a control system and their power supply.
Sourcing I/O modules supply (or source) current to sinking field devices.
Sinking I/O modules receive (or sink) current from sourcing field devices.
Sourcing — A term used to describe current flow between an I/O device
and SLC I/O circuit — typically, a sourcing device or circuit provides a path
to the source, high, or positive side of power supply.
Surge Current Per Point — The maximum amplitude and duration (pulse)
of current allowed for a given period of time and temperature.
Surge Suppressor — A device used to absorb voltage transients created by
energizing an inductive load to reduce electrical noise or to protect the output
circuit. For example, an R–C network, MOV (metal oxide varistor) or diode.
Token — The logical right to initiate communications. In a multi–master
network a single token is passed between initiators to make sure two nodes
do not transmit at the same time.
UVPROM — An Ultra–Violet light erasable Programmable Read Only
Memory module used to back up, store, or transfer SLC 500 programs. The
SLC 5/01 and 5/02 can only read from a UVPROM. An external PROM
programmer is used to program (write to) the device.
Voltage Category — The nominal voltage used to describe the module.
Watts Per Point — The maximum heat dissipation that can occur in each
field wiring point when energized.