Omega Products TX253 User Manual

Thermocouple and

(1.3)

(0.8)

21345

(0.2)

(1.3)

(1.7)

RTD (Pt100) Transmitters

TX250 Series

Starts at

119

⻬ Thermocouple and RTD

Models Available

⻬ Adjustable Span ⻬ Non-Isolated

4 to 20 mAdc Output

⻬ Miniature Size ⻬ Fits in NB1

Protection Head

⻬ High Accuracy ⻬ High RFI Immunity ⻬ Dip-Switch Multi-range ⻬ Low Cost

TX250 Series Thermocouple Input

The TX250 Series are non-isolated 2-wire transmitters which convert the T/C thermoelectric voltage into a standardized load-independent, 4 to 20 mA, process current.

The TX250 Series are housed in metal enclosures and fit into NB1 connection heads. The transmitter’s enclosure provides excellent RFI immunity.

The transmitter calibration is set by 6 dip-switches located behind the top cover. There are 3 basic models which cover the various T/C Types. TX251 is for T/C Types K, T and J; TX252 is for Type E and TX253 is for Type R and S.

Dip-switch arrays select the T/C Type, and set the “Zero” course level and the “Span” course range.

Zero and Span trimmers provide the fine tuning calibration. To scale the units in the field, calibration equipment is required.

TX254 RTD Input

The TX254 is a non-isolated 2-wire transmitter which converts the measuring signal of a 3-wire 100 Ω Pt RTD into a standardized load-independent, 4 to 20 mA, current which is linearly proportional to the measured temperature.

TX254, $119, shown

actual size.

The TX254 transmitter is provided with excellent lead resistance compensation and Pt-100 linearization conforming to BS1904 and DIN 43760 characteristics (a = 0.00385).The transmitter calibration is set by 6 dip-switches located behind the top cover.

3 dip-switches set the lower measured course temperature and the other 3 dip-switches set the measured course temperature span.

Zero and Span trimmers provide the fine tuning calibration. To scale the units in the field, calibration equipment is required.

General Specifications

Output Current:

4 to 20 mA, 28 mA limited Supply Voltage: 10 to 36 Vdc (24 Vdc recommended)

Supply Variation Effect:

<0.001%/1V change

Accuracy: Better than 0.1% of span Load Resistance:

Rmax (Ω) = (Vsupply - 10)/0.02

Temperature Stability:

<0.01% of span/1°C

Operating Temperature:

-20 to 70°C (-4 to 158°F)

Humidity: 5 to 95% RH, non-condensed Housing: Diecast zinc alloy Mounting Holes: 5 mm ID

suitable for 8-32 screw Dimensions: 33 H x 44 mm Dia. (1.3 x 1.7") including the terminal block

Weight: 50 g (1.5 oz)

TX250 Thermocouple Input Specifications

Input:

TX251: Thermocouple Type K, T, J TX252: Thermocouple Type E TX253: Thermocouple Type R, S

Calibration: 2 “Zero” DIP switches,

3 “Span” DIP switches and 2 finetuning trimmers

N-43

TX251, $119, shown

actual size.

Cold Junction Error:

±0.9°C (±1.6°F) typical (3°C [5.4°F] for R and S) for 0 to 60°C (32 to 140°F)

Linearity (refer to mV input):

<0.08% of span

Note: Transmitters are linear to the mV input from the thermocouple, not to temperature.

TX250 RTD Input Specifications

Input: 3-wire Pt-100 according

to BS 1904 and DIN 43760 characteristics

Input Span Range: 30 to 800°C Input Zero Range: -50 to 200°C

Dimensions: mm (in)

–

–+–

Input

T/C

Output

4 to 20 mA

10 to 36 Vdc

Negative Lead

Positive Lead

LOAD

1 2 3 4 5

Calibration: 3 “Zero” DIP switches,

–

Input

RTD

Output

4 to 20 mA

10 to 36 Vdc

Pt100

LOAD

1 2 3 4 5

3 “Span” DIP switches and 2 finetuning trimmers

Sensor Lead Resistance:

50 Ω maximum (2 ways)

Lead Compensation Error:

<0.05°C/10Ω lead resistance

Sensor Excitation: <1 mA Linearity: Better than 0.08% of span

To Order (Specify Model Number)

Non-Isolated Transmitter Unscaled Model Number Price Description

TX251 $119 Transmitter for J, K, T Type thermocouples TX252 119 Transmitter for E Type thermocouples TX253 119 Transmitter for R, S Type thermocouples TX254 119 Transmitter for 3-wire 100 Ω Platinum RTDs TX-SCALED 55 Scaling charge (specify input type and range) PSR-24S 60 Regulated power supply, 24 Vdc, 400 mA, screw terminal PSR-24L 60 Regulated power supply, 24 Vdc, 400 mA, UL, stripped leads PSR-24L-230 60 Regulated power supply, 24 Vdc, 400 mA, stripped leads, 230 Vac input, CE PSU-93 40 Unregulated power supply, 16 to 23 Vdc, 300 mA max, screw terminal

To order transmitter with probe as part of a head and well assembly please consult Temperature Application Engineering. Note: The TX250 series requires thermocouple or RTD input simulation to scale the output for a particular temperature range.

To order unit scaled by OMEGA order TX-SCALED, $55, and specify (1) input type, (2) low end of range, (3) high end of range (specify C or F).

Ordering Examples: TX251, transmitter, TX-SCALED, scaling charge, calibrated for Type K thermocouple with range of 0 to 800°C, $119 + 55 = $174. TX254, transmitter, $119.

Transmitter

TX250 Series transmitters, shown with industrial thermocouple head. See page A-131.

inside!

Connection Diagram: TX251, TX252, TX253

Connection Diagram: TX254

Range and Span Table

Model No. Input Type Span Range* Minimum Span Zero Offset Range

-100 to 750°C 85°C -100 to 50°C

-148 to 1380°F 155°F

TX251 -100 to 1350°C 105°C -100 to 100°C

-148 to 2440°F 190°F

-100 to 400°C 100°C -100 to 100°C

-148 to 750°F 180°F

-100 to 1000°C 75°C -100 to 30°C

TX252 -148 to 1832°F 135°F

0 to 1750°C 600°C 0 to 750°C

TX253

32 to 3180°F 1080°F

0 to 1750°C 600°C 0 to 750°C

32 to 3180°F 1080°F

TX254

Notes: (1) Thermocouple models output proportional to mV output of thermocouple. Not linearized to temperature. (2) Non-isolated unit for use with ungrounded probes.

Note: Factory setting; TX251 Type K 0 to 1000°C, TX252 Type E 0 to 1000°C,

TX253 Type R 0 to 1700°C, TX254 0 to 100°C.

RTD -50 to 750°C 30°C -50 to 200°C

100 Ω Pt -58 to 1380°F

54°F