Thermocouple & RTD Temperature 4-20 mA Current Transmitter

  • Input for thermocouple types J, K, T, E, N, R, S.
  • 2, 3 or 4-wire RTD connection with lead resistance compensation.
  • User selectable spans from entire TC or RTD range down to 15.0°.
  • All ranges factory calibrated.
  • Output resolution: 0.025% of span (12 bits).
  • DIN rail mount package only 22.5 mm thick.
  • Detachable screw-clamp connectors.
  • Optional dual solid state relays for alarm or control.
  • Input for 100 ohm platinum RTDs with DIN and ANSI curves.
  • Upscale or downscale open sensor indication.
  • 2, 20, 200 mA and 5A DC current ranges.
  • Isolated 4-20 mA or 0-10V isolated transmitter outputs, selectable.
  • Output update rate: to 60/sec.
  • Powered by AC or DC.
  • Easy setup using Laurel's PC-based Instrument Setup Software.
Laureate™ 4-20 mA transmitters with the temperature signal conditioner board provide a linearized, highly accurate, stable and repeatable transmitter output for multiple thermocouple types and 100 Ohm platinum RTDs. The meter accepts the outputs of types J, K, T, E, N, R and S thermocouples, plus 100 ohm platinum RTD’s with DIN alpha of 0.00385 and ANSI alpha of 0.003925. The thermocouple or RTD and temperature range, specified in °C or °F, are user-selectable. The temperature range can be as wide as the entire span of the thermocouple or RTD type, or as narrow as 150 counts (such as 15.0°), limited only by considerations of electrical noise and digital filtering time constants.

Cold junction compensation automatically corrects for temperature variations at the thermocouple reference junction at the transmitters. 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. For 3- and 4-wire connections, the transmitter automatically compensates for lead resistance of the sensor.

 All ranges for all temperature sensor types are digitally calibrated at the factory. This eliminates the need for field calibration or drift caused by potentiometers found in non-microcomputer based devices.

All Laureate analog input meters and transmitters allow exceptionally fast read rates. Concurrent Slope (Pat 5,262,780) is a method of analog-to-digital conversion that allows up to 60 conversions per second while integrating the input over a full power cycle. Fast read rates provide true readings and fast response for PID control applications and for peak capture.

The transmitters are housed in a DIN rail case that is only 22.5 mm (0.89") thick. Signal connections are via detachable screw-clamp plugs.

In addition to the 4-20 mA output that would typically be used for signal transmission in an industrial environment, a 0-10V analog output is selectable. Either selection provides 12-bit (0.025%) resolution of output span and is ultra-linear, with the analog output tracking the reading that would be transmitted digitally.

Output isolation from signal and power grounds is provided by a separate on-board transmitter power supply, thereby eliminating potential problems caused by ground loops. The supply can an drive 20 mA into a 500 ohm (or lower) load for 10V compliance, or 10V into 5K ohm (or higher) load for 2 mA compliance.

Transmitter programming is via a three-terminal RS-232 port using Laurel's PC-based Instrument Setup Software. This software can be downloaded from this website at no charge. The required transmitter-to-PC interface cable is available from Laurel (P/N CBL03).


TC Type Range Conformity Error
J -210°C to +760°C
-347°F to +1400°F
K -244°C to +1372°C
-408°F to +2501°F
T 0°C to +400°C
-257°C to 0°C
+32°F to 752°F
-430°F to +32°F
E -240°C to +1000°C
-400°F to +1830°F
N -245°C to +1300°C
-410°F to +2370°F
R -45°C to +1768°C
-49°F to +3214°F
S -46°C to +1768°C
-51°F to +3213°F
Applicable to all thermocouple types
Calibration NIST Monograph 125 (IPTS-68)
Input resistance 1 Gohm
Input current 100 pA
Max lead resistance 1 Gohm max for rated accuracy
Span tempco ±0.003% of reading/ºC
Reference junction tempco ±0.02 deg/deg
Span tempco ±0.003% of reading/ºC
Over-voltage protection 125 Vac
NMR at 50/60 Hz 80 dB plus selectable digital filter from 80 ms to 9.6 s time constant
CMR, DC-60 Hz 120 dB with 500 W imbalance
CMV, DC-60 Hz 250 Vac from power and earth grounds
Open sensor indication 0 mA or > 20mA output, selectable
Pt 100 RTD Input
RTD Alpha Range Conformity Error
-202°C to +850°C
-331°F to +1562°F
-202°C to +631°C
-331°F to +1168°F
Applicable to all RTD types
Calibration, DIN IEC 751 (IPTS-68)
Calibration ANSI NIST Monograph 126
Configuration 2, 3 or 4-wire connection
Excitation current 0.2 mA
Span tempco ±0.003% of reading/ºC
Zero tempco ±0.03 deg/deg
Sensor lead resistance 2-wire, 10 mdeg/W/deg up to 10 W
tempco per conductor 3 & 4-wire, 10 mdeg/W/deg up to 100 W
Over-voltage protection 125 Vac
Open sensor indication 0 mA or > 20mA output, selectable
Thermocouple & RTD
Analog Output
Output Levels 4-20 mA or  0-10 Vdc (selectable)
Compliance, 4-20 mA 10V ( 0-500 ohm load )
Compliance, 0-10V 2 mA ( 5 kOhm load )
Output Resolution 12 bits (4,096 steps)
Output Accuracy ±0.05% of output span
Output Isolation 250V rms working, 2.3 kV rms per 1 minute test
Update Rate, Max 50/sec at 50 Hz, 60/sec at 60 Hz.
Dual Relay Output (optional)
Relay Type Two solid state relays, SPST, normally open, Form A
Load rating 120 mA at 130 Vac or 170 Vdc, 28 ohms series resistance.
Power Input
Standard power 95-240V AC ±10% or 90-300V DC
Low power option 12-30V AC or 10-48V DC
Frequency DC or 47-63 Hz
Power Isolation 250V rms working, 2.3 kV rms per 1 min test.
Case Dimensions 120 x 101 x 22.5 mm
Case Mounting 35 mm rail per DIN EN 50022
Electrical Connections Detachable screw terminal connectors
Operating Temperature 0°C to 70°C
Storage Temperature -40°C to 85°C
Relative Humidity 95% at 40°C, non-condensing
Pinout Laureate 4-20 mA Thermocouple Transmitter
(shown with optional dual relay output)
Thermocouple Transmitter Connection
RTD Connections with Excitation & Lead Compensation
The Laureate temperature transmitter allows 2-, 3- and 4-wire RTD hookup to the J5 connector. The transmitter applies an excitation current of 0.2 mA, which it monitors to make ratiometric corrections for excitation supply variations.
In 2-wire hookup, the transmitter senses the voltage drop across the 100 ohm RTD and both lead wires. The effect of the lead wires can be measured and subtracted by shorting out the RTD during transmitter setup.
In 3- and 4-wire hookup, the transmitter senses the voltage drop across the 100 ohm RTD and both lead wires as well as the voltage drop across the RTD and one lead wire. This allows the transmitter to determine the effect of one lead wire and mathematically subtract the effect of both lead wires.
Operation as a Fast ON/OFF Controller or Supervisory Monitor
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.

Multiple setpoint operating modes are individually selectable for each relay, as explained in the dual-setpoint controller page. Relay duty cycles and chatter can be minimized with programmable hysteresis and time delays. 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. The relay modes have to be non-latching, since 4-20 mA temperature transmitters do not offer external reset.

Strain Gauge Transmitter

Externally Powered 4-Wire Process Transmitter

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