63230-300-212 Glossary
April 2001
195
© 2001 Schneider Electric All Rights Reserved
rms—rootm eansquare. Circuit monitors are true
rms sensing devices.See also
harmonics (rms
).
sag/swell—fluctuation (decreasing or
increasing)in voltage or current in the electrical
system being monitored.See also,
voltagesag
and
voltageswell
.
scale factor—multipliers that the cir cuit monitor
uses to makevalues fit into the register where
informationis stored.
SMS—see System Manager Software.
synchronizeddemand—demand intervals in
the circuitmonitor that can be synchronized with
another deviceusing an external pulse, a
command sent overcommunications, or the
circuit monitor’sinternal real-time clock.
System Manager Software( SMS)—software
designedby POWERLOGIC for use in evaluating
powermonitoring and control data.
system type—aunique code assigned to each
type of systemw iringconfiguration of the circuit
monitor.
thermaldemand—demand calculationbased on
thermal response.
TIF/IT—telephoneinfluence factor used to
assess theinterference of power distribution
circuits withaudio communications circuits.
TotalHarmonic Distortion (THD or thd)—
indicatesthe degree to which the voltage or
current signalis distorted in a circuit.
total power factor—
see powerfactor
.
transient—suddenchange in the steady-state
conditionof voltageor current.
troubleshooting—evaluatingand attempting to
correct problemswith the circuit monitor’s
operation.
true power factor—see
power factor
.
undervoltage—decreasein effective voltage to
less than 90% forlonger than one minute.
VAR—volt ampere reactive.
VFD—vacuum fluorescentdisplay.
voltageinterruption—compl ete loss of power
where no voltageremains in the circuit.
voltage sag—a brief decrease in effective
voltagelasting more than one minute.
voltage swell—increase in effective voltage for
up to one minute in duration.
voltage transfo rmer (VT)—see
potentialtransformer
.
voltage unbalance—percentagedifference
between eachphase voltage with respect to the
averageof all phase voltages.
waveform capture—c an be done for all current
and voltagechannels in the circuit monitor.