The Laureate™ RTD meter is factory calibrated for four Resistance Temperature Detector (RTD) types: 100-ohm platinum (Pt100) with DIN alpha of 0.00385, 100-ohm platinum (Pt100) with ANSI alpha of 0.003902, 10-ohm copper with alpha of 0.00427, and 120-ohm nickel with alpha of 0.00672. The entire span of each RTD type is presented in a single range. The RTD type, unit of measure (°C or °F) and resolution (1°, 0.1° or 0.01°) are selectable from the front panel or via the meter's serial interface. Display in Kelvin or Rankin is selected by offsetting the Celsius or Fahrenheit ranges. Typical accuracy is better than ±0.1°C (±0.2°F).
RTD connections can be via 2, 3 or 4 wires. With 3 or 4-wire connections, the meter automatically compensates for changes in lead resistance to the sensor. With 2-wire connection, the meter can measure and then subtract the lead wire resistance.
All ranges for all RTD types are digitally calibrated at the factory, with calibration factors stored in an EEPROM on the signal conditioner board. This allows temperatures sensors and signal conditioner boards to be changed in the field without recalibrating the meter.
High read rates at up to 60 or 50 conversions per second while integrating the signal over a full power cycle are provided by Concurrent Slope (US Pat 5,262,780) analog-to-digital conversion. High read rates are ideal for peak or valley capture, real-time computer interface, and control. Peak and valley values are standard. These may be displayed via a front panel pushbutton command or a control signal at the rear connector, or be transmitted as serial data.
Digital filtering is selectable for electrically noisy environments or resolution to 0.01°, including a batch averaging filter and an adaptive moving average filter which provides a choice of 8 time constants from 80 ms to 9.6 s. When a significant change in signal level occurs, that filter adapts by briefly switching to the shortest time to follow the change, then reverts back to the selected time constant. In a selectable Auto filter mode, the filter time constant is automatically selected based on detected signal noise.
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.
RTD hookup can be via 2, 3 or 4 wires to the J5 connector. The meter applies an excitation current of 256 µA (Pt100 and Ni120) or 5 mA (Cu10).
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In 4-wire hookup, different pairs of leads are used to apply the excitation current and sense the voltage drop across the RTD for ratiometric operation, so that the IR drop across the excitation leads is not a factor. |
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In 3-wire hookup, the meter senses the combined voltage drop across the RTD plus two excitation leads. It also senses the voltage drop across one excitation lead, and then subtracts twice this voltage from the combined total. This technique effectively subtracts all lead resistance and compensates for ambient temperature changes if the two excitation leads are identical. |
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In 2-wire hookup, the meter senses the combined voltage drop across the RTD and both lead wires. The voltage drop across the lead wires can be measured by shorting out the RTD during meter setup, and this voltage is then automatically subtracted from the combined total. However, changing resistance of the lead wires due to ambient temperature changes will not be compensated. |
RTD Metal |
Alpha | R at 0°C |
R at top of range |
Excitation Current* |
Range | Max Error |
Platinum Pt100 |
0.003850 (DIN) |
100Ω | 390.48Ω at 850°C |
196 µA | -202°C to +850°C -331°F to +1562°F |
±0.03°C ±0.01% of rdg ±0.05°F ±0.01% of rdg |
Platinum Pt100 |
0.003902 (ANSI) |
100Ω | 394.36Ω at 850°C |
196 µA | -202°C to +631°C -331°F to +1168°F |
±0.04°C ±0.01% of rdg ±0.07°F ±0.01% of rdg |
Nickel Ni120 |
0.00672 | 120Ω | 380.31Ω at 260°C |
196 µA | -80°C to +260°C -112°F to +500°F |
±0.05°C ±0.01% of rdg ±0.09°F ±0.01% of rdg |
Copper Cu10 |
0.00427 | 9.035Ω | 19.116Ω at 260°C |
5.0 mA | -100°C to +260°C -148°F to +500°F |
±0.05°C ±0.01% of rdg ±0.09°F ±0.01% of rdg |
Display | |
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Readout | 5 LED digits, 7-segment, 14.2 mm (.56") |
Color | Red or green LED |
Indicators | Minus sign, 2 red LED lamps |
Accuracy | |
Calibration, Pt 100 DIN | Per IEC 751 (ITS-90) |
Calibration, Pt 100 ANSI | NIST Monograph 126 |
Calibration, Ni 120 | DIN 43760 |
Max error at 25°C, Pt100 | ±0.04°C (±0.07°F) ±0.01% of reading |
Span tempco | ±0.003% of reading/°C |
Zero tempco | ±0.03 deg/deg |
Provision for user calibration | Multiplier of RTD resistance plus offset in degrees |
Electrical | |
Connection | 2, 3 or 4-wire |
Overvoltage protection | 125 Vac |
Open sensor indication | Flashes full-scale |
Sensor lead resistance | 2-wire, 10 mdeg/Ω/deg up to 10Ω |
Tempco per conductor | 3 & 4-wire, 10 mdeg/Ω/deg up to 100Ω |
A-to-D Conversion | |
Technique | Concurrent Slope™ (Pat 5,262,780) |
A-to-D rate | 60/s at 60 Hz, 50/s at 50 Hz |
Output update rate | 56/s at 60 Hz, 47/s at 50 Hz |
Display update rate | 3.5/s at 60 Hz, 3/s at 50 Hz |
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 (typ. base meter) | 1.2W @ 120Vac, 1.5W @ 240Vac, 1.3W @ 10Vdc, 1.4W @ 20Vdc, 1.55W @ 30Vdc, 1.8W @ 40Vdc, 2.15W @ 48Vdc |
Power Isolation | 250V rms working, 2.3 kV rms per 1 min test |
Ratiometric operation | Automatically compensates for changes in excitation level. |
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 |
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 |
With the optional analog output board, Laureate RTD temperature meters can serve as superb, isolated 4-20 mA transmitters. The analog output is scaled to the display, which is linearized to °C or °F and is exceptionally accurate. The analog output further tracks the high read rate of the meter, at up to 60 readings per second at 60 Hz power. Fast update rates are beneficial in many closed-loop and PID control applications.
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By using the optional dual contact relay or dual solid state relay output options, Laureate temperature meters can monitor processes and provide alarms or shutoffs when these processes exceed normal limits. A band deviation operating mode can be selected for each relay, where an alarm is generated whenever the reading is a selected number of counts above or below the setpoint. Relay operation can be selected as latching or non-latching. When an alarm or shutdown condition is reached, a latched output will remain in the alarm condition until it is reset by a front panel pushbutton, via the serial interface, or via the rear connector.