4-20 mA Current Output RTD Temperature Transmitter

Exceptional linearity & accuracy at high update rates. DIN Rail mounted, digitally programmable.
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4-20 mA Current Transmitter for RTD Temperature
Key Features
  • Factory calibrated for 100Ω platinum, 10Ω copper & 120Ω nickel RTDs
  • 2, 3 or 4-wire RTD connection with lead resistance compensation
  • Upscale or downscale open sensor indication
  • User selectable spans from entire RTD range down to 15.0°
  • Output update rate to 60/sec
  • Output resolution: 0.0015% of span (16 bits)
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		 196 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		 196 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		 196 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
Calibration, Pt 100 DIN
Calibration, Pt 100 ANSI
Configuration
Excitation current
Overall accuracy
Span tempco
Zero tempco
Sensor lead resistance
   tempco per conductor
Over-voltage protection
Open sensor indication		 IEC 751 (IPTS-68)
NIST Monograph 126
2, 3 or 4-wire connection
0.2 mA
±0.01 of full scale ±2 counts
±0.003% of reading/ºC
±0.03 deg/deg
2-wire, 10 mdeg/W/deg up to 10 W
3 & 4-wire, 10 mdeg/W/deg up to 100 W
125 Vac
0 mA or > 20mA output, selectable
Analog Output
Output Levels
Compliance, 4-20 mA
Compliance, 0-10V
Output Resolution
Output Accuracy
Output Isolation
Step response time		 4-20 mA and 0-10 Vdc (selectable)
10V ( 0-500Ω load )
2 mA ( 5 kΩ load )
16 bits (65,536 steps)
±0.02% of output span
250V rms working, 2.3 kV rms per 1 minute test
50 ms
Dual Relay Output (standard)
Relay Type
Load Rating		 Two solid state relays, SPST, normally open, Form A
130 mA at 140 Vac or 180 Vdc
Serial Communications (optional)
Signal Types
Data Rates
Output Isolation
Serial Protocols
Modbus Modes
Modbus Compliance
Digital Addressing
 RS232 or RS485 (half or full duplex)
300, 600, 1200, 2400, 4800, 9600, 19200 baud
250V rms working, 2.3 kV rms per 1 min test
Modbus RTU, Modbus ASCII, Laurel ASCII
RTU or ASCII
Modbus over Serial Line Specification V1.0 (2002)
247 Modbus addresses.
Up to 32 devices on an RS485 line w/o a repeater.
Power Input
Standard Power
Low Power Option
Power Frequency
Power Isolation
Power Consumption		 85-264 Vac or 90-300 Vdc (DC operation not UL approved)
10-48 Vdc or 12-32 Vac
DC or 47-63 Hz
250V rms working, 2.3 kV rms per 1 min test
2W typical, 3W with max excitation output
Mechanical
Dimensions
Mounting
Electrical Connections		 129 x 104 x 22.5 mm case
35 mm rail per DIN EN 50022
Plug-in screw-clamp connectors
Environmental
Operating Temperature
Storage Temperature
Relative Humidity
Cooling Required		 0°C to 55°C
-40°C to 85°C
95% at 40°C, non-condensing
Mount transmitters with ventilation holes at top and bottom.
Leave 6 mm (1/4") between transmitters, or force air with a fan.

 

Pinout

Laureate 4-20 mA RTD Temperature Transmitter

Pinout of RTD temperature transmitter

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).
4-wire hookup of RTD signal conditioner board
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.
3-wire hookup of RTD signal conditioner board 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.
2-wire hookup of RTD signal conditioner board 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.

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