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.
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, WiFi and 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.
AC Voltage FS Range |
AC Voltage to Overrange Flash |
Resolution | Input Resistance |
Error at 25°C ** |
---|---|---|---|---|
200.00 mV | 264.00 mV | 10 µV | 1 MΩ |
± 0.03% of FS ± 2 cts, 0-100% of FS |
2.0000 V | 2.640 V | 100 µV | ||
20.000 V | 26.400 V | 1 mV | ||
200.00 V | 264.00 V | 10 mV | ||
600.0 V* | 650 V | 0.1 V | ± 0.8 V | |
300.0 V | 650 V | 0.1 V | ± 0.8 V |
DC Current Range | AC Current to Overrange Flash |
Resolution | Input Resistance | Error at 25°C ** |
---|---|---|---|---|
2.0000 mA | 264.00 µA | 0.1 µA | 100 Ω | ± 0.03% of FS ± 2 cts, 0-100% of FS |
20.000 mA | 26.400 mA | 1.0 µA | 10 Ω | |
200.00 mA | 264.00 mA | 10 µA | 1 Ω | |
5.000 A | 5.4 A | 1 mA | 0.01Ω | ± 20 mA |
* | For purposes of accuracy calculation, the 600V range is 2000V (20,000 counts), and the 5A range is 20A (20,000 counts). |
Display | |
---|---|
Readout | 5 LED digits, 7-segment, 14.2 mm (.56"), red or green |
Range | -99999 to 99999 or -99990 to 99990 (count by 10) |
Display Update Rate | 3.75/s at 60 Hz power, 3.1/s at 50 Hz power |
Indicators | 1 LED lamp per relay setpoint |
Crest factor Vp / Vrms | 3.00 at full scale range |
Output Update Rate | |
A-to-D rate | 60/s at 60 Hz power, 50/s at 50 Hz power |
Signals > 50/60 Hz | 60/s at 60 Hz power, 50/s at 50 Hz power |
Signals 3 Hz to 50/60 Hz | Same as signal frequency |
Signals DC to 3 Hz | 3 per second |
Maximum Signal | |
Max applied voltage | 600 Vac for 2, 20, 200, 600V ranges, 35 Vac for 0.2V range |
Current protection | 25x for 2 mA, 8x for 20 mA, 2.5x for 200 mA, 1x for 5A |
Power Supply Boards (one required) | |
Voltage, standard | 85-264 Vac or 90-300 Vdc |
Voltage, optional | 12-32 Vac or 10-48 Vdc |
Frequency | DC or 47-63 Hz |
Power consumption (typical, base meter) | 1.2W @ 120 Vac, 1.5W @ 240 Vac, 1.3W @ 10 Vdc, 1.4W @ 20 Vdc, 1.55W @ 30 Vdc, 1.8W @ 40 Vdc, 2.15W @ 48 Vdc |
Power Isolation | 250V rms working, 2.3 kV rms per 1 min test |
Analog Output Board (one optional) | |
Output levels | 4-20 mA, 0-20 mA, 0-10V, -10 to +10V (jumper selectable) |
Current compliance | 2 mA at 10V ( > 5 kΩ load) |
Voltage compliance | 12V at 20 mA (< 600 Ω load) |
Scaling | Zero and full scale adjustable from -99999 to +99999 |
Resolution | 16 bits (0.0015% of full scale) |
Step function response | 80 ms to 99% of final value (typ) |
Isolation | 250V rms working, 2.3 kV rms per 1 min test |
Relay Output Boards (one optional) | |
Dual magnetic relays | 2 Form C, 8A at 250 Vac or 24 Vdc, 0.3A at 250 Vdc, resistive load |
Quad magnetic relays | 4 Form A (NO), 8A at 250 Vac or 24 Vdc, 0.3A at 250 Vdc, resistive load |
Dual solid state relays | 2 Form A (NO), 120 mA at 140 Vac or 180 Vdc, resistive load |
Quad solid state relays | 4 Form A (NO), 120 mA at 140 Vac or 180 Vdc, resistive load |
Relay commons | Isolated commons for dual relays or each pair of quad relays |
Relay isolation | 250V rms working, 2.3 kV rms per 1 minute test |
Step function response | 30 ms (typ) for contact relays, 25 ms (typ) for solid state relays |
Relay latching modes | Latching or non-latching |
Relay active modes | Active on or off, active high or low |
Hysteresis modes | QA passband mode, split hysteresis, span hysteresis |
Communication Boards (one optional) | |
Board selections | RS232, RS485 with dual RJ11 connectors, RS485 with dual RJ45 connectors, USB, Ethernet, USB-to-RS485 gateway, Ethernet-to-RS485 gateway, WiFi with built-in antenna plus USB & RS485, WiFi with external antenna plus USB & RS485 |
Protocols | Laurel Custom ASCII (serial), Modbus RTU (serial), Modbus TCP (Ethernet or WiFi) |
Digital addresses | 247 (Modbus), 31 (Laurel ASCII), |
Isolation | 250V rms working, 2.3 kV rms per 1 min test |
Signal Connections | |
Environmental | |
Operating temperature | 0°C to 55°C standard, -40°C to 70°C with -X option |
Storage temperature. | -40°C to 85°C |
Relative humidity | 95% at 40°C, non-condensing |
Protection | NEMA-4X (IP-65) when panel mounted |
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.
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: