Endress+Hauser S TMT142C Specifications

Technical Information

Omnigrad S TMT142C

Compact Thermometer Temperature transmitter for thermocouples, adjustable via HART protocol

Application

The temperature assembly TMT142C from the Omnigrad S family is a compact thermometer specifically designed to fulfill the requirements of different process industries such as the chemical, petrochemical and energy but even suitable to other general purpose applications. The thermometer assembly TMT142C consists of a thermocouple sensor insert (Type J or K) and an electronic two-wire temperature transmitter providing a 4 to 20 mA output, configurable via HART Thanks to the versatility of its product structure, the TMT142C is easily adaptable to various applications in many different industrial processes.

Your benefits

•HART® protocol for operating the device on site using handheld terminal (DXR375) or remotely via the PC

• Illuminated display, rotatable

• Operation, visualization and maintenance with PC, e.g. using FieldCare or ReadWin® 2000 operating software

• 2-wire transmitter, analog output 4 to 20 mA

• Undervoltage detection responds immediately, output of falsified measured values is prevented

• Highly accurate in entire operating temperature range

protocol.

• Sensor monitoring: Failure conditioning, corrosion detection to NAMUR NE 89; Failure conditioning in event of sensor break or sensor short-circuit, adjustable to NAMUR NE 43

• EMC to NAMUR NE 21, CE

• Sensor insets with thermocouple (Type J or K) made by mineraloxide cables, replaceable

• Thermocouple sensing element type J or K, accuracy class 1 or 2 (IEC 60584)

• Single or double TC element

• Aluminum or Stainless steel (optional) housing with ingress protection degree IP67 or NEMA 4x

• Calibration certificate can be ordered in the product structure

• Output simulation

• Min./max. process value recorded

• Customized measuring range setup or expanded SETUP, see questionnaire

• Approvals: ATEX (EEx ia, EEx d and Staub-Ex), CSA (IS, NI, XP and DIP)

0 1

TI129R/09/en 71022417

TMT142C

Function and system design

Measuring principle In the thermocouple thermometer the sensing element is created by the physical junction of two homogeneous

but different alloys (wires) isolated for the entire length, except in the junction point. The two wires are welded on one side, named ‘measuring or hot junction’, while the free wires side, named ‘reference or cold junction’ is connected to an electrical circuit measuring the electromotive force (mVolts) generated by the different thermoelectric characteristics of the two thermocouple wires when a temperature difference between the hot junction (T1) and the cold junction (T0) occurs. The function linking the electromotive force to the temperatures T1 and T0 depends on the materials utilized in the alloys. These functions are standardized curves, for different alloys couples, by the following international standards: IEC 60584 and ANSI MC96.1.

Measuring system

TMT142R, TMT142C

FieldCare,

RN221N

Commubox

ReadWin 2000

PMC731:PIC0001 Online

1>GroupSelect 2PV 0.7bar

HELP

DXR375

HART Communication

Example of an application of the compact thermometer

The Omnigrad S HART® TMT142C is a compact thermometer with a two-wire transmitter and an input for thermocouples (Type J or K) and an analog output. The LC display shows the current measured value digitally and as a bar graph with an indicator for limit value violation. The TMT142C can be operated via the HART protocol using a handheld terminal (DXR375) or PC (FieldCare or ReadWin

2000 operating software). The sensor construction is based on the IEC 60751 standard, giving high reliability and performance in all the typical industrial environment conditions. The TC sensing elements are created by two types of alloy couples: the type J (Fe-CuNi) or the type K (NiCrNi). The measuring ranges of this temperature sensing elements have different values depending on the couple types. The measuring probe (TC replaceable insert) is installed in a suitable thermowell. Thanks to the spring load construction method, the thermometer insert stays always in contact with the inner tip of the thermowell in order to guarantee the best heating transfer from the process to the sensing element. The transmitter housing is available either in coated aluminum or stainless steel (optional), with or without LC display. The fit between housing, thermowell and cable gland ensures a minimum IP65 (Ingress Protection) grade. The thermowell can be either welded or made from bar-stock material. The thermowells are available in different forms and with many process connections: threads, flanges or weld-in types (see the paragraph “Thermowell”).

Corrosion detection

Sensor connection line corrosion can corrupt the measured value. For this reason, the device gives you the opportunity to detect corrosion for thermocouples and resistance thermometers with a 4-wire connection before measured value corruption takes place.

2 Endress+Hauser

TMT142C

Input

Measured variable Temperature (temperature linear transmission behavior)

Measuring range The transmitter records different measuring ranges depending on the sensor connection and input signals (see

'Type of input').

Type of input

Input Designation Measuring range limits Min. span

Thermocouples (TC)

to NIST Monograph 175, IEC 584

Type J (Fe-CuNi) Type K (NiCr-Ni)

• Internal cold junction (Pt100)

• Accuracy of cold junction: ± 1 K

• Max. sensor resistance 10 kΩ (if sensor resistance is greater than 10 kΩ, error message as per NAMUR NE 89)

-210 to +1200 °C (-346 to 2192 °F)

-270 to +1372 °C (-454 to 2501 °F)

Response time Tests in water at 0.4 m/s (according to IEC 60751; 23 to 33°C step changes), without thermowell:

• t50: 2.5 s

• t90: 7 s

Self heating Negligible

Output

Output signal analog 4 to 20 mA, 20 to 4 mA

Signal on alarm • Underranging:

Linear drop to 3.8 mA

• Overranging: Linear rise to 20.5 mA

50 K 50 K

Load max. (V

Linearization/transmission

Temperature linear, resistance linear, voltage linear

power supply

- 11 V) / 0.022 A (current output)

behavior

Filter 1

order digital filter: 0 to 60 s

Galvanic isolation U = 2 kV AC (input/output)

Input current required ≤ 3.5 mA

Current limit ≤ 23 mA

Switch-on delay 4 s (during switch-on operation I

= 4 mA)

Endress+Hauser 3

Power supply

TMT142C

Electrical connection

Supply voltage U

= 11 to 40 V (8 to 40 V without display), reverse polarity protection

Warning! Power must be fed to the device from an 11 to 40 VDC power supply in accordance with NEC Class 02 (low voltage/current) with short-circuit power limit to 8 A/150 VA.

Cable entry see "Product structure"

Residual ripple Perm. residual ripple U

Sensor

≤ 3 V at Ub ≥ 13.5 V, f

= 1 kHz

max.

11...40 V

11...30 V Ex

4...20 mA

HART - Signal

Accuracy

Response time 1 s per channel

Reference operating conditions

Maximum measured error The accuracy values defined by the IEC 60584 standard, are as follows:

Calibration temperature: +25 °C ± 5 K (77 °F ± 9 °F)

Type Standard tolerance (IEC 60584) Reduced tolerance (IEC 60584)

Class Deviation Class Deviation

J (Fe-CuNi) 2 +/-2.5 °C (-40...333 °C)

+/-0.0075 |t| (333...750 °C)

K (NiCr-Ni) 2 +/-2.5°C (-40...333°C)

+/-0.0075 |t| (333...1200 °C)

(ItI=absolute temperature value in °C)

1 +/-1.5 °C (-40...375 °C)

+/-0.004 |t| (375...750 °C)

+/-0.004 |t| (375...1000 °C)

4 Endress+Hauser

TMT142C

Transmitter maximum measured error

Thermocouples (TC) K, J typ. 0.5 K typ. 0.25 K

1) % relates to the set span. Accuracy = digital + D/A accuracy

2) Only with the "Advanced Electronics" option

Physical input range of the sensors

-20 to 100 mV Thermocouples type: J, K

Designation

Repeatability 0.03% of the physical input range (15 Bit)

Resolution A/D conversion: 18 Bit

With the "Advanced Electronics" option:

0.015% of the physical input range (16 Bit)

Influence of supply voltage ≤ ±0.005%/V deviation from 24 V, related to the full scale value

Long-term stability ≤ 0.1 K/year or ≤ 0.05%/year

Data under reference conditions. % relates to the set span. The larger value applies.

Accuracy

digital D/A

0.02%

Endress+Hauser 5

+ 11 hidden pages