True AC RMS measurement with crest
factor of 3.0 at FS
Fast response: reading 0-16.7 ms
after completion of each
input signal cycle.
0.1% accuracy, 0% to 100%
of span, 10 Hz to 10 kHz
Reads AC only or AC plus DC
0.2, 2, 20, 200 & 600V voltage ranges
with 132% overrange
2, 20, 200 mA & 5A current ranges
with 132% overrange
All ranges factory calibrated
Display flashes at 132% overrange
Scalable to 5 digits for external current shunts or
5A current transformers
Selectable peak or valley display
85-264 Vac universal AC power
Green or red display
NEMA 4X, 1/8 DIN case
Certified to UL 61010C-1 (UL mark), EN 61010-1 (CE mark)
RoHS compliant
Priced competitively with less
capable AC meters Options:
Low voltage power: 10-48 Vdc or 12-32
Vac
2 or 4 output relays, contact or
solid state
Isolated analog output: 4-20 mA, 0-20 mA, 0-10V, 10 to +10V
Serial communications: RS232, RS485, Modbus RS485,
USB, USB-to-RS485 converter
Description
The
Laureate True RMS meter is a 60,000 count digital panel meter with
exceptional performance at half the price of a bench top meter. It can
measure true RMS voltage or current of AC signals where there is considerable distortion of the
waveform, such as rectifier outputs or waveforms chopped by an SCR, TRIAC or transistor
circuit, as illustrated.
True RMS readings
in 0-16 ms after completion of one input signal cycle allow
anomalies to be detected and alarmed before they become expensive problems.
Fast on/off control and
alarm can be achieved with optional dual or quad relays, either contact or
solid state. The meter can also capture peak and valley readings that occur
at the nominal rate of 50/60 Hz.
Accurate
is 0.1% of full scale for signals from DC to 10 kHz and
signal amplitudes down to 0. The
crest factor (Vp / Vrms) is 3.0 at full-scale Vrms of 20,000
counts and a Vp of 60,000 counts. The meter starts to flash overrange at 132%
of full scale Vrms , at which point the available
crest factor is 60,000 / 26,400 = 2.27. Meaningful readings with rated
resolution continue to be obtained up to 212% of full scale Vrms
(42,433 counts) for sinusoidal signals, at which point the available crest
factor is 1.414. For safety reasons, the maximum RMS input signal
should never exceed 600V or 5A. UL certification is for a maximum voltage
of 300 Vrms.
AC or DC coupling is jumper selectable
on the signal conditioner board. AC coupling
accommodates signals from 10 Hz to 10 kHz and is suitable for
applications such as measuring AC ripple on a DC power supply. DC coupling
accommodates signals from 0 to 10 kHz. Multiple integral cycles are
averaged for signals above 50/60 Hz. A single cycle is captured for signals
from 3 Hz to 50/60 Hz. Below 3 Hz and at DC, the capture rate is 3/sec.
Use with current
Transformers. High common mode rejection allows stable
readings with current shunts located on the high side of the line. Five amp input
capability allows the output of 5A current transformers to be applied directly to the
meter, with no need for a stepdown transformer. The meter reading can easily be scaled
for the current transformer ratio. Digital scaling and calibration eliminate
zero and span drift associated with potentiometers in non-microcomputer based meters.
Digital filtering is selectable for noisy signals.
Designed for flexibility. An isolated
sensor excitation output is standard. Optional plug-in boards for
communications and control include an analog output
board, dual or quad relay boards,
and serial communications boards. Laureate meters may be powered from
85-264 Vac or optionally
from 12-32 Vac or 10-48 Vdc. The display is available
with red or green LEDs. The 1/8 DIN case meets NEMA 4X (IP65) specifications from the front
when panel mounted. Any setup functions and front panel keys can be
locked out for simplified usage and security.
± 0.1% of FS,
0-100% of FS,
10 Hz to 10 kHz (AC coupling)
or DC to 10 kHz (DC coupling)
600.0 V *
650 V
100 mV
1 MΩ
± 2V
AC Current (0 to 100% of full scale range)
AC Current
FS Range
AC Current to
OverrangeFlash
Resolution
Input
Resistance
Error
at 25°C
2.0000
mA
20.000 mA
200.00 mA
2.6400
mA
26.400 mA
264.00 mA
0.1
µA
1 µA
10 µA
100
Ω
10 Ω
1 Ω
± 0.1% of FS,
0-100% of FS,
10 Hz to 10 kHz (AC coupling)
or DC to 10 kHz (DC coupling)
5.000 A
5.4 A
1 mA
0.01
Ω
±
20 mA
* The 600V range is UL certified to 264V.
For purposes of accuracy calculation, the 600V range is 2000V
(20,000 counts), and the 5A range is 20A (20,000 counts).
5 LED digits, 7-segment, 14.2 mm (.56"), red
or green
-99999 to 99999 or -99990 to 99990
(count by 10)
3.75/s at 60 Hz power, 3.1/s at 50 Hz power
1 LED lamp per relay setpoint
3.00 at full scale range
2.27 at 132% of FS range (display flashes)
1.414 at 212% of FS range (maximum sinusoidal signal)
Output Update
Rate
A-to-D rate
Signals > 50/60 Hz
Signals 3 Hz to 50/60 Hz
Signals DC to 3 Hz
60/s at 60 Hz
power, 50/s at 50 Hz power
60/s at 60 Hz power, 50/s at 50 Hz power
Signal frequency
3 per second
Maximum Signal
Max applied
voltage
Current
protection
600 Vac for 2, 20, 200, 600V ranges, 50 Vac for
0.2V range
25x for 2 mA, 8x for 20 mA, 2.5x for 200 mA, 1x for 5A
Output Levels
Current compliance
Voltage compliance
Scaling
Resolution
Isolation
4-20 mA, 0-20 mA, 0-10V,
-10 to +10V (jumper selectable)
2 mA at 10V ( > 5 kOhm load)
12V at 20 mA ( < 600 Ohm load)
Zero and full scale adjustable from -99999 to +99999
16 bits (0.0015% of full scale)
250V rms working, 2.3 kV rms per 1 min test
2 Form C contact relays or 4 Form A contact
relays (NO) 2 or 4 Form A, AC/DC solid state relays (NO) 8A at 250 Vac
or 24 Vdc for contact relays 130 mA at 140 Vac or 180 Vdc for solid state
relays
Isolated commons for dual relays or each pair of quad relays 250V rms working, 2.3 kV rms per 1 min test
Board Selections
Protocols
Data Rates
Digital Addresses
Isolation
RS232, RS485, Modbus RS485, USB, USB-to-RS485
converter
Modbus RTU, Modbus ASCII, simpler Laurel ASCII
300 to 19200 bps
247 (Modbus), 31 (Laurel ASCII),
250V rms working, 2.3 kV rms per 1 min test
Signal Connections
Environmental
Operating
Temperature
Storage Temperature
Relative Humidity
Protection
0°C to
60°C
-40°C to 85°C
95% at 40°C, non-condensing
NEMA-4X (IP-65) when panel mounted
Using Laureate
Meters and Counters to Instrument an AC Line
Why Measure AC Power?
Many AC loads, such as
electrical motors, will only operate reliably if the AC line voltage and frequency are
within specified tolerances; otherwise permanent damage to expensive plant equipment may
occur.
Drops in line voltage or frequency may indicate an excessive load
and the possibility of equipment damage. Laureate meters and counters are low-cost
means to instrument and alarm AC power lines with great accuracy:
AC RMS Voltmeter
and Ammeter, as documented in this page. True RMS capability allows the display of RMS voltage for non-sinusoidal waveshapes, such as
square waves from a UPS. A built-in 5 A range
can be used to display currents up to 5.000 A with 1 mA resolution or accept the
output of 5 A current transformers. The 200.00 mV range can be used with external current
shunts. With either transformers or shunts, scaling of the input current is easily
accomplished via the meter's front panel pushbutton switches.
Frequency Meter.
Inverse period is
used to determine AC line frequency to six-figure accuracy (60.0000 or 50.0000) in a few
line cycles plus 30 ms.
Phase Angle &
Power Factor Meter. Two
signals with identical periods are applied to Channels A and B. A phase
angle resolution of 1º, 0.1º or 0.01º is
selectable. Accuracy is .01% up to 100 Hz, .1% at 1 kHz, and 1% at 10 kHz.
Application Example Using
Laureate Meters to Synchronize Two Motor Generators
Successful synchronization of two motor
generators requires that the voltage outputs of the generators be close to each other,
that the two frequencies be identical, and that the voltage waveshapes be in phase.
The two voltages can be
measured by two Laureate AC RMS Voltmeters, which offer 200.00 V and
600.0 V ranges. Or a
single meter can be multiplexed by using an external toggle switch.
Two frequencies A &
B can be
measured to six-figure accuracy by a single
Laureate Dual Channel Counter, where each
channel monitors a generator. The two AC neutrals must be tied to meter ground. Pressing a
front-panel key toggles the reading between the channels. The meter
can also display frequency A - frequency B, or frequency A / frequency B
without toggling.
Ordering
Guide Laureate™ True AC RMS Voltage & Current Panel Meters Click
on the radio buttons to build a model number with pricing (shown below the
Ordering Guide).