Laurel Electronics provides digital panel meters / controllers, totalizers, counters, loop-powered meters, temperature meters, for all types of transducers or process indication & control.

True AC RMS Voltage or Current Modbus or Laurel ASCII Protocol Serial I/O Transmitter

Serial ASCII or Modbus Transmitter, AC RMS Voltage or Current Input

DIN Rail mounted, digitally programmable. Exceptional accuracy at high update rates.

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Features
Selectable Modbus or Laurel ASCII protocol.	Modbus RTU or ASCII modes, 2-wire connection, up to 247 digital addresses.
Output accuracy: ±0.01% of span for DC signals (±0.1% for AC rms).	Output update rate to 50 or 60/sec.
Easy setup using Laurel's PC-based Instrument Setup Software.	Optional isolated scalable analog output (4-20 mA or 0-10V).
Optional dual solid state relays for alarm or control.	Optional custom curve linearization (Extended main board).
0.2, 2, 20, 200, 300V & 600V input ranges	2, 20, 200 mA and 5A input ranges.
All ranges factory calibrated.	Output accuracy: ±0.01% of full scale input.
Peak capture.	AC coupled, frequencies from 10 Hz to 10 kHz.

Description

AC Ranges. The Laureate Serial I/O, AC RMS input transmitter provides six voltage ranges and four current ranges, all factory calibrated and jumper selectable. The 200.00 mV and 2.0000 V ranges provide a high input impedance of 22 Mohm to minimize the load on the voltage signal. A special 5.000A range allows the output of 5A current transformers to be applied directly to the transmitter, with no need for a stepdown transformer. The current readings can easily be scaled digitally as needed.

True RMS. Precision circuitry is used to determine the root-mean-square of complex waveforms from 10 Hz to 10 kHz. Spikes up to 2.4 times the maximum of each range are accurately measured. This provides a crest factor (Vp / Vrms) of 240 for a signal amplitude of 1% of full scale, decreasing to 2.4 at 100% of full scale. Laureate AC RMS input transmitters duplicate the performance and programmable features of their Laureate AC RMS digital panel meter counterparts.

High Accuracy

Maximum error as a function of frequency
and signal amplitude

The typical accuracy is 99.9% of full scale, decreasing to 99.8% for low frequency at high amplitude, or high frequency at low amplitude. The above graph shows that maximum error is 0.1% of full scale over all frequency ranges of interest to AC power measurement. Error increases to 0.2%, represented by the two shaded areas, at low frequency and high amplitude, or high frequency and low amplitude.

Crest factor increases in inverse proportion to signal amplitude. As shown on the same graph, the maximum crest factor (Vp / Vrms) is 2.4x at full-scale amplitude, increasing to 240 at 1% of full-scale amplitude.

The Laureate RMS meter utilizes the same high-speed analog-to-digital conversion method as all other Laureate panel meters. However, the meter settling time and control response to a step change in AC amplitude are limited by the RMS converter circuit to approximately 1 second.

Interface Options

Plug-in isolated analog output, dual setpoint controller, or RS-232/485 communications, can upgrade the Laureate from a simple monitor to system interface and control.

Built-in Flexibility & Safety

Laureates may be powered from 95-240 Vac ±10% or 90-300 Vdc, or optionally from 12-30 Vac or 10-48 Vdc. They are available with red or green LEDs. They are housed in a 1/8 DIN case that meets NEMA 4X (IP65) specifications from the front when panel mounted. Any setup functions and front panel keys may be locked out for simplified usage and security.

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General Specifications
AC Voltage Range	Resolution	Input Ohms	Typ Error at 25°C 10 Hz to 10 kHz
200.00 mV 2.000 V 20.000 V 200.00 V 600.0 V * 300.0 V	10 µV 100 µV 1 mV 10 mV 100 mV 100 mV	22 M 22 M 1 M 1 M 1 M 1 M	0.15% FS 0.15% FS 0.15% FS 0.15% FS 0.15% FS 0.15% FS
AC Current (1% to 100% of full scale)
AC Current Range	Resolution	Input Ohms	Typ Error at 25°C 10 Hz to 10 kHz
2.0000 mA 20.000 mA 200.00 mA 5.000 A	0.1 µA 1.0 µA 10 µA 1.0 mA	100 10 1 0.01	0.15% FS 0.15% FS 0.15% FS 0.25% FS

Display
Readout Range Indicators	5 LED digits, 7-segment, 14.2 mm (.56"), red or green -99999 to 99999 or -99990 to 99990 (count by 10 with rounding) 2 red LED lamps
Accuracy
Span Tempco Zero Tempco Crest Factor	0.005% of reading/°C 0.1 count/°C 2.4x at 100% of full scale
Response Time
RMS to DC A-to-D rate Output Update Display Update	1 s conversion settling time 60/s at 60 Hz, 50/s at 50 Hz 56/s at 60 Hz, 47/s at 50 Hz 3.5/s at 60 Hz, 3/s at 50 Hz
Maximum Signal
Max applied voltage Over-current protection	600 Vac for 20, 200, 600V ranges, 125 Vac other ranges 25x for 2 mA, 8x for 20 mA, 2.5x for 200 mA, 1x for 5 A
Power
Voltage, standard Voltage, optional Frequency Power Isolation	95-240 Vac ±10% or 90-300 Vdc 12-30 Vac or 10-48 Vdc DC or 47-63 Hz 250V rms working, 2.3 kV rms per 1 min test
Excitation Output (standard)
5 Vdc 10 Vdc 24 Vdc Output isolation	5 Vdc ±5%, 100 mA 10 Vdc ±5%, 120 mA 24 Vdc ±5%, 50 mA 50 Vdc to meter ground
Analog Output (optional)
Output levels Compliance Scaling Resolution Isolation	0-10V, 0-20 mA, 4-20 mA (jumper selectable) 2 mA at 10V (5 kOhm load), 12V at 20 mA (0-60 ohm load) Zero and full scale adjustable from -99999 to +99999 12 bits (0.025% of full scale) 250V rms working, 2.3 kV rms per 1 min test
Dual Contact Relay Outputs (optional)
Relay Type Load Rating Isolation	Form C 8A at 250 Vac or 24 Vdc 250V rms working, 2.3 kV rms per 1 min test
Dual Solid State Relay Outputs (optional)
Relay Type Load Rating Isolation	SPST, normally open, Form A 120 mA at 130 Vac or 170 Vdc, 28 ohms series resistance. 250V rms working, 2.3 kV rms per 1 min test
Serial Data I/O (optional)
Board Selections Protocols Data Rates Digital Addresses Isolation	RS232, RS485, Modbus RS485 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

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AC line monitoring using a LaurelAC RMS Voltmeter, AC RMS Ammeter, and AC Line Frequency 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. Motor generators and UPS systems will only operate reliably with the load for which they are rated. 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 AC power lines with great accuracy:

AC RMS Voltmeter. Full-scale ranges of interest are 200.00 V with 10 mV resolution and 600.0 V with 100 mV resolution. True RMS capability allows the display of RMS voltage for non-sinusoidal waveshapes, such as square waves from a UPS.
AC RMS Ammeter. A built-in 5 A range can be used to display currents up to 5.000 A with 10 mA resolution, or to 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 to 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 Meter. Two signals with identical periods are applied to Channels A and B of the Laureate phase angle meter. A display from -180º to +180º is obtained by timing the rising edge of one channel and the falling edge of the other channel. A 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.

Using Laurel Meters to Synchronize Two Motor Generators

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.

The two frequencies 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.

Phase angle can be measured using the Laureate Phase Meter.

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FLW, Inc - 3505 Cadillac Ave - Bldg E - Costa Mesa, CA. - 92626 - USA - Ph (714) 751 - 7512 - Fax (714) 751 - 0213