iTemp TMT142B

Summary

Product identification

The Endress+Hauser iTEMP TMT142B is a temperature field transmitter with HART® protocol and Bluetooth® capabilities.

Application

• Converts various input signals (RTD, TC, resistance, voltage) into a scalable, analog 4 to 20 mA output signal.
• Features reliability, long-term stability, high precision, and advanced diagnostic functions.
• Suitable for demanding environmental conditions with an optional stainless steel housing.
• Can be installed as an intrinsically safe apparatus in hazardous areas.

Input

Measured variable

• Temperature (temperature-linear transmission behavior)
• Resistance
• Voltage

Measuring range

The device supports a variety of resistance thermometers (RTD), thermocouples (TC), resistance transmitters (Ω), and voltage transmitters (mV) with specified measuring range limits and minimum spans. See the official PDF for exact tabulated values.

• Resistance thermometer (RTD): Supports various standards including IEC 60751, JIS C1604, DIN 43760, GOST 6651, and OIML R84. Ranges vary by type (e.g., Pt100, Pt1000, Ni100, Cu50) from –200 °C to +1100 °C (–328 to +2012 °F).
  • Connection types: 2-wire, 3-wire, or 4-wire.
  • Sensor current: ≤ 0.3 mA.
  • Wire resistance compensation: possible for 2-wire (0 to 30 Ω), up to max. 50 Ω per wire for 3-wire and 4-wire.
• Resistance transmitter:
  • 10 to 400 Ω (min. span 10 Ω)
  • 10 to 2000 Ω (min. span 10 Ω)
• Thermocouples (TC): Supports types A, B, C, D, E, J, K, L, N, R, S, T, U as per various standards (IEC 60584, ASTM E230, DIN 43710, GOST R8.585). Ranges vary from –270 °C to +2500 °C (–454 to +4532 °F). Minimum span typically 50 K (90 °F).
• Voltage transmitter (mV): –20 to 100 mV (min. span 5 mV).

Output

Output signal

• Analog output: 4 to 20 mA, 20 to 4 mA (invertible).
• Signal encoding: FSK ±0.5 mA via current signal.
• Data transmission rate: 1200 baud.
• Galvanic isolation: U = 2 kV AC for 1 minute (input/output).

Failure information

Failure information as per NAMUR NE43:

• Underranging: Linear decrease from 4.0 to 3.8 mA.
• Overranging: Linear increase from 20.0 to 20.5 mA.
• Failure (e.g., sensor failure, short-circuit): ≤ 3.6 mA ("low") or ≥ 21 mA ("high"), selectable. "High" alarm can be set between 21.5 mA and 23 mA.

Load

Maximum load Rb max. = (Ub max. - 11 V) / 0.023 A.

Linearization/transmission behavior

• Temperature-linear
• Resistance-linear
• Voltage-linear

Network frequency filter

• 50/60 Hz

Filter

• 1st order digital filter: 0 to 120 s.

Protocol-specific data

• HART® specification: 7
• Device address in multi-drop mode: 0 to 63.
• HART® load: min. 250 Ω.

Write protection for device parameters

• Hardware: via DIP switch.
• Software: user role-based concept with password assignment.

Switch-on delay

• ≤ 2 s until HART® communication starts.
• ≤ 7 s until the first valid measured value is present at the current output.
• During switch-on delay: Ia ≤ 3.8 mA.

Power supply

• Non-hazardous areas: 11 to 36 VDC (standard), protected against polarity reversal.
• Hazardous areas: See Ex documentation.
• The device must be powered by a unit operating with a limited energy circuit according to UL/EN/IEC 61010-1.

Current consumption

• 3.6 to 23 mA.
• Minimum current consumption: ≤ 3.5 mA.
• Multidrop mode: 4 mA.
• Current limit: ≤ 23 mA.

Terminals

• Max. wire cross-section: 2.5 mm² (12 AWG) plus ferrule.

Overvoltage protection

• Optional surge arrester available.
• Connection data: Maximum continuous voltage (rated voltage) UC = 36 VDC.
• Surge current resistance: Lightning surge current D1 (10/350 µs) Iimp = 1 kA (per wire); Nominal discharge current C1/C2 (8/20 µs) In = 5 kA (per wire) or 10 kA (total).
• Series resistance per wire: 1.8 Ω, tolerance ±5 %.

Performance characteristics

Response time

• RTD and resistance transmitter (Ω measurement): ≤ 1 s.
• Thermocouples (TC) and voltage transmitters (mV): ≤ 1 s.
• Reference temperature: ≤ 1 s.

Reference operating conditions

• Calibration temperature: +25 °C ±3 K (+77 °F ±5.4 °F).
• Supply voltage: 24 V DC.
• 4-wire circuit for resistance adjustment.

Maximum measured error

Errors are specified according to DIN EN 60770 under reference conditions and represent ±2 s (Gaussian distribution). See the official PDF for exact tabulated values for various sensor types and ranges.

• Resistance thermometers (RTD) and resistance transmitters: Errors are detailed for digital values (via HART®) and analog output (D/A conversion), including sensor-specific formulas.
• Thermocouples (TC) and voltage transmitters: Errors are detailed for digital values (via HART®) and analog output (D/A conversion), including sensor-specific formulas.

Sensor adjustment

Sensor-transmitter-matching

• Callendar-Van Dusen coefficients: For Pt100 resistance thermometers, using coefficients A, B, and C to match the sensor and transmitter for improved accuracy.
• Linearization for copper/nickel resistance thermometers: Using polynomial equations with coefficients A and B specific to the sensor's calibration data.
• 1-point adjustment: Shifts the sensor value (offset).

Current output adjustment

• Correction of the 4 and/or 20 mA current output value.

Operating influences

Influences of ambient temperature and supply voltage on measured error are detailed for both RTD/resistance transmitters and TC/voltage transmitters. See the official PDF for exact tabulated values.

Installation

Mounting location

• Directly to sensor or remote mounting using brackets.
• Display can be mounted in four positions.

Environment

Ambient temperature

• –40 to +85 °C (–40 to +185 °F) (for hazardous areas, see Ex documentation).
• Without display: –40 to +85 °C (–40 to +185 °F).
• With display: –40 to +80 °C (–40 to +176 °F).
• With overvoltage protection module: –40 to +85 °C (–40 to +185 °F).
• Display legibility may be affected at temperatures below –30 °C (–22 °F).

Storage temperature

• Without display: –50 to +100 °C (–58 to +212 °F).
• With display: –40 to +80 °C (–40 to +176 °F).
• With overvoltage protection module: –50 to +100 °C (–58 to +212 °F).

Humidity

• Permitted: 0 to 95 %.

Climate class

• As per IEC 60654-1, Class Dx.

Degree of protection

• Die-cast aluminum or stainless steel housing: IP66/67, Type 4X.

Shock and vibration resistance

• Caution: Vibrations must not exceed specifications. Resonance may occur with L-shaped mounting brackets.

Electromagnetic compatibility (EMC)

• CE compliance: Meets IEC/EN 61326 series and NAMUR Recommendation EMC (NE21).
• Maximum measured error: <1% of measuring range.
• Interference immunity: As per IEC/EN 61326 series, industrial requirements.
• Interference emission: As per IEC/EN 61326 series, Class B equipment.
• Shielded sensor cables are recommended for lengths ≥ 30 m (98.4 ft).

Overvoltage category

• II

Degree of contamination

• 2

Mechanical construction

Design, dimensions

• Die-cast aluminum or optional stainless steel (316L) housing.
• Electronics module and connection compartment.
• Display attachable in 90° stages.

Weight

• Aluminum housing (with display): approx. 1.4 kg (3 lb).
• Stainless steel housing (with display): approx. 4.2 kg (9.3 lb).

Materials

• Housing: Die-cast aluminum (AlSi10Mg/AlSi12 with powder coating) or 316L stainless steel (1.4404).
• Sensor terminals: Nickel-plated brass (gold flashed).
• Nameplate: Aluminum (anodized).

Cable entries

• Available in 3x thread ½" NPT, 3x thread M20, or 3x thread G½".

Operability

Operating concept

• Configuration programs via HART® protocol.
• Miniature switch (DIP switch) for hardware settings.

Local operation

• LC display (backlit, attachable in 90° stages).
• Displays measured value, units (°C, °F, K, %), status, and symbols.
• No operating elements directly on the display; located on the electronics module.

Remote operation

• Configuration via HART® communication using specialized software.

Bluetooth® wireless technology

• Optional interface for operation and configuration using the SmartBlue app.
• Range: 25 m (82 ft) (with display window), 10 m (33 ft) (without display window) under reference conditions.
• Communication is encrypted with password protection.
• Can be deactivated.

Certificates and approvals

• CE mark: Confirms compliance with EC directives.
• EAC mark: Confirms compliance with EEU guidelines.
• Ex approvals: Information available from sales center; separate Ex documentation required for explosion protection data.
• CSA C/US: Complies with relevant CSA standards.
• HART® certification: Registered by FieldComm Group, meets HART® Communication Protocol Specifications, Revision 7.

MTTF

• Without Bluetooth®: 152 years.
• With Bluetooth®: 114 years. (According to Siemens SN-29500 at 40 °C (104 °F)).

Ordering information

Detailed ordering information and product configuration available via the Endress+Hauser website and Product Configurator.

Accessories

Various device-specific and communication-specific accessories are available. These include dummy plugs, cable glands, pipe mounting brackets, overvoltage protection modules, Commuboxes, and the Field Xpert SMT70 tablet PC.

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Disclaimer: This extraction may miss figures, footnotes, or revisions. Contractual data must match the OEM PDF revision used on the project.

Official datasheet (PDF)

Lenntech datasheet mirror