Laureate™ True RMS AC Voltage & Current Meter with 1 Cycle Update at 50/60 Hz

200 mV - 600 V and 2 mA - 5 A full-scale ranges
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AC-Meter
Features
  • 0.2, 2, 20, 200 & 600V AC or AC+DC voltage ranges with 132% overrange
  • 2, 20, 200 mA & 5A AC or AC+DC current ranges with 132% overrange
  • True AC RMS measurement with crest factor of 3.0 at full scale
  • Fast response: reading in 0-16.7 ms after each signal cycle to full accuracy
  • Accurate to 0.1% of full scale, 0.1% to 100% of FS, 10 Hz to 10 kHz
  • Universal 85-264 Vac / 90-300 Vdc or 10-48 Vdc / 12-32 Vac power
  • Wide choice of options:
    - 2 or 4 relays, mechanical or solid state (isolated)
    - Analog output, 4-20 mA, 0-10V, or -10V to +10V (isolated)
    - Serial data I/O: Ethernet, USB, RS485, RS232 (isolated)
    - Custom curve linearization, rate from consecutive readings
Description
True RMS digital panel meter by Laurel Electronics

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.
  • Accuracy is 0.1% of full scale for signals from DC to 10 kHz and signal amplitudes down to 0.1% of full scale. 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. ETL certification is for a maximum voltage of 300 Vrms.

PowerAC 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.

Power 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 filtering is selectable for noisy signals.

Designed for system use. Optional plug-in boards for communications and control include Ethernet and other serial communication boards, dual or quad relay boards, and an isolated analog output board. Laureates 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. All power and signal connections are via UL / VDE / CSA rated screw clamp plugs.

Specifications Back to top
AC Voltage (0.1% to 100% of full scale range)
AC Voltage FS Range AC Voltage to Overrange Flash Resolution Input Resistance Error at 25°C
200.00 mV
2.0000 V
20.000 V
200.00 V
264.00 mV
2.640 V
26.400 V
264.00 V
10 µV
100 µV
1 mV
10 mV
1 MΩ
1 MΩ
1 MΩ
1 MΩ
± 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 (0.1% to 100% of full scale range)
AC Current FS Range AC Current to OverrangeFlash Resolution Input Resistance Error at 25°C ± 2 cts
2.0000 mA
20.000 mA
200.00 mA
2.6400 mA
26.400 mA
264.00 mA
0.1 µA
1.0 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 ETL certified to 300V. For purposes of accuracy calculation, the 600V range is 2000V (20,000 counts), and the 5A range is 20A (20,000 counts).
Both AC Voltage & Current
Display
Readout
Range
Display Update Rate
Indicators
Crest factor Vp / Vrms
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 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
Power
Voltage, standard
Voltage, optional
Frequency
Power Isolation
85-264 Vac or 90-300 Vdc (DC operation not ETL certified)
12-32 Vac or 10-48 Vdc
DC or 47-63 Hz
250V rms working, 2.3 kV rms per 1 min test
Analog Output (optional)
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 kΩ load)
12V at 20 mA ( < 600Ω 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
Relay Outputs (optional)
Relay Types

Current Ratings

Output common
Isolation
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
120 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
Serial Data I/O (optional)
Board Selections

Protocols
Data Rates
Digital Addresses
Isolation
Ethernet, Ethernet-to-RS485 server, USB, USB-to-RS485 server, RS485 (dual RJ11), RS485 Modbus (dual RJ45), RS232.
Modbus RTU, Modbus ASCII, Laurel ASCII protocol
300 to 19200 baud
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
Applications Back to top
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.
  • Phase angle can be measured using the Laureate Phase Meter.


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 1ֲ÷, 0.1ֲ÷ or 0.01ֲ÷ is selectable. Accuracy is .01% up to 100 Hz, .1% at 1 kHz, and 1% at 10 kHz.
Ordering Guide Back to top
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). Prices are in US dollars and do not include shipping or duty charges (export sales).

Configured model number L10000RMV1
Configured price per model $270
Quantity 1
Extended price $270
Quantity
Main Board
L1 Standard Main Board, Green LEDs
L2 Standard Main Board, Red LEDs
L3 Extended DPM, green LEDs
L4 Standard Extended DPM, red LEDs
$230
$230
$260
$260
Power
0 Isolated 85-264 Vac or 90-300 Vdc
1 Isolated 12-32 Vac or 10-48 Vdc
$0
$30
Relay
Output
(isolated)
0 None
1 Two 8A Contact Relays
2 Two 120 mA Solid State Relays
3 Four 8A Contact Relays
4 Four120 mA Solid State Relays
$0
$80
$55
$100
$75
Analog
Output
(isolated)
0 None
1 Isolated 4-20 mA, 0-20 mA, 0-10 V, -10 to +10V
$0
$90
Digital
Interface
(isolated)
0 None
1 RS232
2 RS485(dual RJ11 connectors)
4 RS485 Modbus (dual RJ45 connectors)
5 USB
6 USB-to-RS485 device server
7 Ethernet
8 Ethernet-to-RS485 device server
$0
$60
$80
$90
$60
$100
$120
$150
Signal
Input
(isolated)
  True AC RMS Volts
RMV1 200.00 mV
RMV2  2.0000 V
RMV3 20.000 V
RMV4 200.00 V
RMV5 600.0 V (range ETL certified to 300V)
RMV6 250.0 V
 
$40
  True AC RMS Amps
RMA1 2.0000 mA
RMA2 20.000 mA
RMA3 200.00 mA
RMA4 5.000 A
 
$40
Add-on
Options
CBL01  RS232 cable, RJ11 to DB9, 7 ft. Connects RS232 ports of meter
and PC.
CBL02 USB to RS232 adapter cable. Combination of CBL02 and CBL01
connects meter RS232 port to PC USB port. Combination of CBL02 and
CBL04 connects transmitter RS232 terminals to PC USB port.
CBL03-1 6-wire data cable, RJ11 to RJ11, 1 ft. Used to daisy chain meters
via RS485.
CBL03-7 6-wire data cable, RJ11 to RJ11, 7 ft. Used to daisy chain meters
via RS485.
CBL05 USB cable, A-B. Connects USB ports of meter and PC.
CBL06  USB to RS485 adapter cable, half duplex, RJ11 to USB. Connects
meter RS485 port to PC USB port.
NL  Meter Lens with Button Pads but no Laurels Logo
BL  Meter Lens without Button Pads or Laurels Logo
IPC Splash-proof Cover
BOX1 NEMA-4 Enclosure
BOX2 NEMA-4 Enclosure plus IPC
$19
$39
$8
$8
$15
$39
$5
$5
$40
$140
$180
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