iTemp TMT71

Summary

Product identification

• Product Name: iTEMP TMT71
• Product Type: Temperature transmitter
• Document ID: TI01393T/09/EN/04.22-00
• Document Date: 2022-03-18

Application

The iTEMP TMT71 is a universal temperature transmitter designed for converting various input signals into a scalable, analog 4 to 20 mA output signal. It is characterized by its reliability, long-term stability, high precision, and advanced diagnostic functions, making it suitable for critical processes requiring a high level of safety and risk reduction.

• Universal Input: Supports resistance thermometers (RTD), thermocouples (TC), resistance transmitters (Ω), and voltage transmitters (mV).
• Installation Options:
  • In a terminal head, form B (flat face).
  • Optional: In a field housing for Ex d applications.
  • Optional: For DIN rail mounting.

Benefits

• Safe operation in hazardous areas with international approvals.
• Reliable operation due to sensor and device monitoring.
• Diagnostics information according to NAMUR NE107.
• Optional attachable measured value display TID10.
• Integrated Bluetooth® interface for wireless display and configuration via Endress+Hauser SmartBlue app.
• Optional fast, tool-free wiring with push-in terminal technology.

Function and system design

The device electronically records and converts industrial temperature measurement signals. It is a 2-wire device with one measuring input and one analog output. It can transmit converted signals from RTDs, TCs, resistance, and voltage inputs as a 4 to 20 mA current signal.

Measuring principle

Electronic recording and conversion of various input signals in industrial temperature measurement.

Measuring system

• 1 x RTD/TC input.

Diagnostics

• Cable open-circuit, short-circuit of sensor wires.
• Incorrect wiring.
• Internal device errors.
• Overrange/underrange detection.
• Device temperature overrange/underrange detection.
• Corrosion detection as per NAMUR NE89.
• Low voltage detection: If supply voltage drops below a required value, the analog output drops to < 3.6 mA for approximately 5 seconds.
• Diagnostics simulation for testing higher-level systems.

Input

Resistance thermometer (RTD)

• Connection type: 2-wire, 3-wire, or 4-wire.
• Sensor current: ≤ 0.3 mA.
• Wire resistance compensation: Possible for 2-wire circuits (0 to 30 Ω).
• Sensor wire resistance: Up to max. 50 Ω per wire for 3-wire and 4-wire connections.

Resistance transmitter

Thermocouples

Voltage transmitter (mV)

• Range: –20 to 100 mV
• Min. span: 5 mV

Output

• Output signal: 4 to 20 mA, 20 to 4 mA (invertible).
• Galvanic isolation: U = 2 kV AC for 1 minute (input/output).
• 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.
• Linearization/transmission behavior: Temperature-linear, resistance-linear, voltage-linear.
• Mains filter: 50/60 Hz.
• Filter: 1st order digital filter: 0 to 120 s.

Electrical

• Power supply:
  • Head transmitter: 10 V ≤ Vcc ≤ 36 V.
  • DIN rail device: 11 V ≤ Vcc ≤ 36 V.
  • Protected against polarity reversal.
  • Values for hazardous areas are in separate Ex documentation.
• Current consumption:
  • 3.6 to 23 mA.
  • Minimum current consumption: 3.5 mA.
  • Current limit: ≤ 23 mA.
• Switch-on delay: ≤ 7 s until the first measured value signal is present at the current output. During switch-on delay, Ia ≤ 3.8 mA.
• Overvoltage category: II.
• Pollution degree: 2.

Mechanical / hydraulic

Installation

• Mounting location options:
  • Terminal head Form B (flat face) as per DIN EN 50446.
  • Separated from process in a field housing (wall or pipe mounting).
  • With DIN rail clip on a DIN rail as per IEC 60715 (TH35).
  • DIN rail device for mounting on a TH35 mounting rail as per EN 60715.
• Orientation: When using DIN rail devices with thermocouple/mV measurement, increased deviation may occur depending on installation and ambient conditions.

Dimensions

• Head transmitter:
  • Housing diameter: 44 mm (1.73 in).
  • Housing height (with screw terminals): 30 mm (1.18 in).
  • Housing height (with push-in terminals): Varies.
• DIN rail device:
  • Width: 12.5 mm (0.49 in).
  • Height (with screw terminals): 114 mm (4.49 in).
  • Height (with push-in terminals): 111.5 mm (4.39 in).
  • Length: 116 mm (4.57 in).
• Field housing (TA30A):
  • Dimensions: 107.5 (4.23 in) x 68.5 (2.7 in) x 28 (1.1 in).
  • Weight: 330 g (11.64 oz).
• Field housing (TA30A with display window):
  • Dimensions: 107.5 (4.23 in) x 91.6 (3.61 in) x 28 (1.1 in).
  • Weight: 420 g (14.81 oz).
• Field housing (TA30H):
  • Dimensions: 125 (4.92 in) x 89.5 (3.52 in) x 28 (1.1 in).
  • Weight (Aluminum): approx. 640 g (22.6 oz).
  • Weight (Stainless steel): approx. 2400 g (84.7 oz).
• Field housing (TA30H with display window):
  • Dimensions: 125 (4.92 in) x 115 (4.53 in) x 28 (1.1 in).
  • Weight (Aluminum): approx. 860 g (30.33 oz).
  • Weight (Stainless steel): approx. 2900 g (102.3 oz).
• Field housing (TA30D):
  • Dimensions: 107.5 (4.23 in) x 110 (4.3 in) x 28 (1.1 in).
  • Weight: 390 g (13.75 oz).

Weight

• Head transmitter: approx. 40 to 50 g (1.4 to 1.8 oz).
• DIN rail device: approx. 100 g (3.53 oz).
• Field housing: See specifications above.

Materials

All materials are RoHS-compliant.

• Housing: Polycarbonate (PC).
• Terminals:
  • Screw terminals: Nickel-plated brass, gold-plated or tin-plated contacts.
  • Push-in terminals: Tin-plated brass, contact springs 1.4310, 301 (AISI).
• Potting compound:
  • Head transmitter: QSIL 553.
  • DIN rail housing: Silgel612EH.
• Field housing: Aluminum, polyester powder coated or Stainless steel 316L.

Degree of protection

• Head transmitter with screw terminals: IP 00.
• Head transmitter with push-in terminals: IP 30.
• Installed in field housing TA30A, TA30D, TA30H: IP 66/68 (NEMA Type 4x encl.).
• DIN rail device: IP 20.

Shock and vibration resistance

• Vibration resistance:
  • Head transmitter: 2 to 100 Hz at 4g (increased vibration stress).
  • DIN rail device: 2 to 100 Hz at 0.7g (general vibration stress).
• Shock resistance: As per KTA 3505.

Environment

• Ambient temperature range: –40 to +85 °C (–40 to +185 °F). For hazardous areas, see Ex documentation.
• Storage temperature:
  • Head transmitter: –50 to +100 °C (–58 to +212 °F).
  • DIN rail device: –40 to +100 °C (–40 to +212 °F).
• Altitude: Up to 4000 m (4374.5 yards).
• Humidity:
  • Max. rel. humidity: 95% as per IEC 60068-2-30.
  • Condensation: Permitted for head transmitter, not permitted for DIN rail transmitter.
• Climate class:
  • Head transmitter: C1 as per IEC 60654-1.
  • DIN rail device: B2 as per IEC 60654-1.

Operability

• Local operation:
  • Head transmitter: No display or operating elements. Optional attachable display TID10 can be used.
  • DIN rail device: Power LED and Status LED. Service interface for configuration tool.
• Wireless operation: Optional Bluetooth® interface for configuration via SmartBlue app.
  • Range: 10 m (33 ft) in terminal head/field housing with display, or DIN rail housing; 5 m (16.4 ft) in terminal head/field housing without display window.
  • Security: Encrypted communication and password protection.
  • Bluetooth® can be deactivated.
  • Simultaneous use of Bluetooth® and attachable display is not possible.

Certificates and approvals

• CE mark: Complies with EC directives.
• EAC mark: Complies with EEU guidelines.
• Ex approval: Information available upon request.
• CSA C/US: Meets requirements for Process Control Equipment.
• Marine approvals: Available upon request (e.g., DNVGL).
• Radio approval:
  • Europe: RED 2014/53/EU.
  • USA: FCC 15.247.
  • Canada: Industry Canada licence-exempt RSS standard(s).

Reliability

• MTTF:
  • Without Bluetooth®: 168 years.
  • With Bluetooth®: 123 years.

Performance characteristics

Response time

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

Measured error

• Maximum measured error: <1% of measuring range (EMC).
• Reference operating conditions: Calibration temperature +25 °C ±3 K, supply voltage 24 V DC, 4-wire circuit for resistance adjustment.
• Measured error data: Corresponds to ±2 σ (Gaussian distribution), includes non-linearities and repeatability.

Long-term drift

See the official PDF for exact tabulated values.

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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)

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