Thermocouple Transmitter, 4-20 mA & Serial Data Outputs

Exceptional linearity & accuracy at high update rates. DIN Rail mounted, digitally programmable.

4-20 mA and Serial Data Output Thermocouple Transmitter

Features

  • 4-20 mA, 0-20 mA, 0-10V or -10V to +10V transmitter output, 16 bits, isolated
  • RS232 or RS485 serial data output, Modbus or TDM ASCII protocol, isolated
  • Dual 120 mA solid state relays for alarm or control, isolated
  • Factory calibrated for thermocouple types J, K, T, E, N, R, S in one range
  • User selectable input span from entire thermocouple range down to 15.0°
  • Output update rate to 60/sec
  • Analog output resolution 0.0015% of span (16 bits), accuracy ±0.02% of span
  • Universal 85-264 Vac / 90-300 Vdc or 10-48 Vdc / 12-32 Vac power
  • DIN rail mount housing only 22.5 mm wide, detachable screw-clamp connectors
Description

The thermocouple transmitter provides a linearized, highly accurate, stable and repeatable transmitter output for thermocouple types J, K, T, E, N, R or S. The thermocouple 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 thermocouple type, or as narrow as 150 counts (such as 15.0°), limited only by considerations of electrical noise and digital filtering time constants.

Thermocouple signal conditioner board

Digital calibration of all thermocouple 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. Cold junction compensation automatically corrects for temperature variations at the thermocouple reference junction at the transmitter. Open sensor indication is standard and may be set up to indicate either upscale or downscale.

Fast read rate at up to 50 or 60 conversions per second while integrating the signal over a full power line cycle is ideal for peak or valley capture and for real-time computer interface and control.

Standard features of transmitters include:

  • 4-20 mA, 0-20 mA, 0-10V or -10V to +10V analog transmitter output, isolated, jumper-selectable and user scalable. All selections provide 16-bit (0.0015%) resolution of output span and 0.02% output accuracy of a reading from -99,999 to +99,999 counts that is also transmitted digitally. Output isolation from signal and power grounds eliminates potential ground loops.
  • Serial communications output, RS232 or RS485 (half or full duplex), jumper selectable. Three protocols are user selectable: Modbus RTU, Modbus ASCII, or TDM ASCII. Modbus operation is fully compliant with Modbus Over Serial Line Specification V1.0 (2002). The TDM ASCII protocol is simpler than the Modbus protocol and is recommended when all devices are s.
  • Dual solid state relays, isolated, for alarm or control. Rated 120 mA at 140 Vac or 180 Vdc.
  • Universal 85-264 Vac power. Low-voltage 10-48 Vdc or 12-32 Vac power is optional.

Easy Transmitter programming is via TDM'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 TDM (P/N CBL04).

Specifications
TC Types Range Conformity Error
J -210°C to +760°C (-347°F to +1400°F) ±0.09°C (±0.16°F)
K -244°C to +1372°C (-408°F to +2501°F) ±0.1°C (±0.17°F)
T 0°C to +400°C (32°F to 752°F)
-257°C to 0°C (-430°F to +32°F)
±0.03°C (±0.05°F)
±0.2°C (±0.36°F)
E -240°C to +1000°C (-400°F to +1830°F) ±0.18°C (±0.32°F)
N -245°C to +1300°C (-410°F to +2370°F) ±0.10°C (±0.17°F)
R -45°C to +1768°C (-49°F to +3214°F) ±0.17°C (±0.31°F)
S -46°C to +1768°C (-51°F to +3213°F) ±0.12°C (±0.22°F)
Analog Input
Calibration NIST Monograph 125 (IPTS-68)
Input resistance 1 GΩ
Input current 100 pA
Max lead resistance 1 kΩ max for rated accuracy
Overall accuracy ±0.01 of full scale ±2 counts
Span tempco ±0.003% of reading/°C
Ref junction tempco ±0.02 deg/deg
Overvoltage protection 125 Vac
NMR at 50/60 Hz 80 dB plus selectable filter from 80 ms to 9.6 s time constant
CMR, DC-60 Hz 120 dB with 500Ω imbalance
CMV, DC-60 Hz 250 Vac from power and earth grounds
Open sensor indication 0 mA or > 20 mA output, selectable
Analog Output (standard)
Output Levels 4-20 mA, 0-20 mA, 0-10 Vdc, -10 to +10Vdc (user selectable)
Compliance at 20 mA 10V (0-500Ω load)
Compliance at 10V 2 mA (5 kΩ or higher load)
Output Resolution 16 bits (65,536 steps)
Output Accuracy 0.02% of output span plus conversion accuracy
Output Isolation 250V rms working, 2.3 kV rms per 1 minute test
Step response time 50 ms
Serial Data Output (standard)
Signal Types RS232 or RS485 (half or full duplex), jumper selectable
Data Rates 300, 600, 1200, 2400, 4800, 9600, 19200 baud
Output Isolation 250V rms working, 2.3 kV rms per 1 min test
Serial Protocols Modbus RTU, Modbus ASCII, TDM ASCII
Modbus Compliance Modbus over Serial Line Specification V1.0 (2002)
Ethernet Connector RJ45 jack for 10/100 Base-T Ethernet cable
RS232/485 Connector Screw terminals for easy daisy chaining
Digital Addresses 247 for Modbus, 31 for TDM ASCII
Dual Relay Output (standard)
Relay Type Two solid state relays, SPST, normally open, Form A
Load Rating 120 mA at 140 Vac or 180 Vdc
Power Input
Standard Power 85-264 Vac or 90-300 Vdc
Low Power Option 10-48 Vdc or 12-32 Vac
Power Frequency DC or 47-63 Hz
Power Isolation 250V rms working, 2.3 kV rms per 1 min test
Power Consumption 2W typical
Mechanical
Dimensions 129 x 104 x 22.5 mm case
Mounting 35 mm rail per DIN EN 50022
Electrical Connections Plug-in screw-clamp connectors
Environmental
Operating Temperature 0°C to 55°C
Storage Temperature -40°C to 85°C
Relative Humidity 95% at 40°C, non-condensing
Cooling Required Mount transmitters with ventilation holes at top and bottom. Leave 6 mm (1/4") between transmitters, or force air with a fan.
Pinout
 LT transmitter pinout

Operation as a Fast ON/OFF Controller or Supervisory Monitor

Temperature controller operation of  temperature meters and transmitters

With the optional dual solid state relay output option, which has a typical response time of only 17 ms, 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.

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