Appendix 7 Terminology
A
25
Appendix
LAN
LAN is the abbreviation of Local Area Network. The LAN was developed as a network for
transferring data through a PC within a local area, such as an office, factory, or school.
This device comes equipped with the LAN adapter Ethernet 10/100Base-T.Use a twisted-
pair cable to connect this device to the hub (central computer) of your LAN. The maximum
length of the cable connecting the terminal and the hub is 100 m. Communications using
TCP/IP as the LAN interface protocol are supported.
RS-232C
The RS-232C is a serial interface established by the EIA (Electronics Industries Associa-
tion), and conforms to the specifications for DTE (data terminal equipment) and DCE (data
circuit terminating equipment) interface conditions.
Using the signal line part of the RS-232C specifications with this unit allows you to use an
external printer or GPS box.
SD memory card
A type of flash memory card.
TIME PLOT interval
The recording interval. This setting applies to TIMEPLOT and SD memory card recording.
USB-F
(USB function)
An interface for exchanging data with a host controller (typically a computer) connected
with a USB cable. For this reason, communication between functions is not possible.
Event
Power supply quality parameters are necessary in order to investigate and analyze power
supply issues. These parameters include disturbances such as transients, dips, swells,
interruptions, flicker, and frequency fluctuations. As a rule, the term “event" refers to the
state detected based on thresholds for which abnormal values and abnormal waveforms
for these parameters have been set. Events also include timer and repeat event settings,
which are unrelated to power supply quality parameters.
Inter-harmonics
All frequencies that are not a whole-number multiple of the fundamental frequency. Inter-
harmonics include intermediate frequencies and inter-order harmonics, and the term refers
to RMS values for the spectral components of electrical signals with frequencies between
two contiguous harmonic frequencies.
(Inter-harmonics of the order 3.5 assume a drive of 90 Hz or similar rather than a frequency
synchronized to the fundamental wave of an inverter or other device. However, inter-har-
monics do not generally occur in high-voltage circuits under present-day conditions. Most
inter-harmonics are currently thought to be caused by the circuit load.)
External event function
Functionality for generating events by detecting a signal input to the instrument's external
event input terminal and recording measured values and event waveforms at the time of
detection. In this way, events are generated based on an alarm signal from a device other
than the PW3198. By inputting an operating signal from an external device, an operation
start or stop trigger can be applied in order to record waveforms with the PW3198.
Coordinated universal
time (UTC)
The official time used worldwide. Although UTC is almost identical to Greenwich Mean
Time (GMT), which is based on astronomical observations, UTC is determined by measur-
ing 1 SI second using an atomic clock. Regular adjustments ensure that GMT and UTC dif-
fer by no more than 1 second.
Out of crest factor
The crest factor expresses the size of the dynamic range of input on the measurement
device and can be defined with the following expression.
Crest factor = crest value (peak value)/RMS value
For example, when measuring a distorted wave with a small RMS and a large peak on a
measurement device with a small crest factor, because the peak of the distorted wave
exceeds the detection range of the input circuit, an RMS or harmonic measurement error
occurs.
When you increase the measurement range, the peak does not exceed the input circuit’s
detection range, but because the resolution of the RMS decreases, measurement errors
may occur.
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100
50 2
50
0
-50
-100
[A]
Measurement is not possible
Measurement is
not possible
A measurement device with a small crest factor
(When the crest factor is 2 for a 50 A range)
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