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4-20 mA Current Output
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Standard Features
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Description The Laureate 4-20 mA RTD temperature transmitter provides a linearized, highly accurate, stable and repeatable transmitter output for 100 ohm platinum, 10 ohm copper and 120 ohm nickel RTDs. Pt 100 platinum RTDs can have a DIN alpha of 0.00385 or ANSI alpha of 0.00392. The RTD type and temperature range, specified in °C or °F, are user-selectable. The temperature range can be as wide as the entire span of the RTD type or as narrow as 150 counts (such as 15.0°), limited only by considerations of electrical noise and digital filtering time constants.
Fast read rate at up to 50 or 60 conversions per second while integrating the signal over a full power line cycle is provided by Concurrent Slope (Pat 5,262,780) analog-to-digital conversion. High read rate is ideal for peak or valley capture and for real-time computer interface and control. Three analog transmitter settings are jumper selectable: 4-20 mA, 0-20 mA or 0-10V. All selections provide 16-bit (0.0015%) resolution of output span and 0.02% output accuracy. The output tracks the reading from -99,999 to +99,999 counts that would be transmitted digitally. For DC signals, this reading has a rated accuracy of ±0.01% of full scale input and can be scaled in software. Output isolation from signal and power grounds eliminates potential ground loop problems. The supply can drive 20 mA into a 500 ohm (or lower) load for 10V compliance, or 10V into a 5K ohm (or higher) load for 2 mA compliance. Standard features of Laureate temperature transmitters include:
Easy Transmitter programming is via Laurel's Instrument Setup Software, which runs on a PC under MS Windows. This software can be downloaded from this website at no charge. The required transmitter-to-PC interface cable is available from Laurel (P/N CBL04). |
Digital
calibration of all
RTD ranges is performed the factory, with calibration data stored
in EEPROM on the signal conditioner board. This allows signal
conditioner boards and ranges to be changed in the field with no need for
recalibration. Open sensor indication is standard and may be set up to indicate either upscale or
downscale. RTD excitation is provided by the transmitter. RTD connections can be of the 2-, 3-
or 4-wire type. With 3- and 4-wire connections, the transmitter automatically compensates for
lead resistance of the sensor.
Specifications
Laureate 4-20 mA RTD Temperature Transmitter
| RTD Metal |
Alpha |
R
at 0°C |
R at top of range |
Excitation Current |
Range |
Conformity Error |
| Platinum |
0.003850 (DIN) |
100Ω |
390.48Ω at 850°C |
256 μA | -200°C to
+850°C -328°F to +1562°F |
±0.03°C ±0.05°F |
| Platinum |
0.003902 (ANSI) |
100Ω |
394.36Ω at 850°C |
256 μA | -200°C to
+850°C -328°F to +1168°F |
±0.04°C ±0.07°F |
| Nickel | 0.00672 | 120Ω |
380.31Ω at 260°C |
256 μA | -80°C
to +260°C -112°F to +500°F |
±0.05°C ±0.09°F |
| Copper | 0.00427 | 9.035Ω |
19.116Ω at 260°C |
5.0 mA | -97°C
to +260°C -143°F to +500°F |
±0.05°C ±0.09°F |
| RTD Input | |
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Calibration, Pt
100 DIN |
IEC 751 (IPTS-68) |
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Analog Output (standard) |
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Output Levels |
4-20 mA, 0-20 mA, 0-10 Vdc (jumper selectable) |
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Dual Relay Output (standard) |
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Relay Type |
Two solid state relays, SPST, normally open,
Form A |
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Serial Communications (standard) |
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Signal Types |
RS232 (default) or RS485, 2 or 4-wire (user
selectable) |
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Power Input |
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Standard Power |
85-264 Vac or 90-300 Vdc (DC operation not UL
approved) |
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Mechanical |
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Dimensions |
120 x 101 x 22.5 mm |
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Environmental |
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Operating Temperature |
0°C to 55°C |
Pinouts
Laureate 4-20 mA RTD Temperature Transmitter
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RTD hookup can be via 2, 3 or 4 wires to the J5 connector. The transmitter applies an excitation current of 196 μA (Pt 100 and Ni 120) or 5 mA (Cu 10). | |
| In 4-wire hookup, different pairs of leads are used to apply the excitation current and sense the voltage drop across the RTD, so that the IR drop across the excitation leads is not a factor. | ||
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In 3-wire hookup, the transmitter 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 transmitter 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 transmitter 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. |
Operation as a
Fast ON/OFF Controller
or Supervisory Monitor
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With the optional dual solid state relay output
option, which has a typical response
time of only 17 ms, Laureate temperature meters
and transmitters can
serve as extremely fast and accurate ON/OFF controllers
for closed-loop temperature control.
They can also serve as
supervisory process monitors and provide alarms or shutoffs when processes exceed normal
limits.
Ordering
Guide
Laureate 4-20 mA RTD Temperature Transmitter
Click on the radio buttons to build a model number with pricing (shown below the Ordering Guide).
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