300TX High Accuracy Thermocouple or Pt100 Temperature Transmitter

The 300TX is a 4-20mA temperature transmitter which can be housed in a probe terminal head suitable for a DIN standard block. With ranges for thermocouple and Pt100 sensors, the units offer an exceptionally wide range of span adjustment which reduces the need for stockholding different temperature ranges. A novel feature is the non-interactive span and zero potentiometer action which is time saving and convenient when calibrating or re-scaling.

• 4-20mA, 2 wire loop
• Low cost
• High accuracy
• In-head mounting, DIN standard fixing
• Pt100 or thermocouples type J, K
• High reliability
• Non-interactive span & zero pots for calibration
• Permits virtually unlimited length of cable run in low-cost copper
• More expensive thermocouple extension cable not required
• Rugged construction
• Effective input ‘noise ‘rejection
• CE compliant
• RoHS compliant

Specification:

Ranges Thermocouple to IEC 584

Type J 0-300°C
Type K 0-200°C
Type K 0-1100°C

PT100 to IEC751, 3 wire

0 to 100°C
0 to 200°C
(Junctions/ sensors must be insulated from sheath)

Output

4-20mA loop powered, max 30mA.
Directly proportional to mV input for thermocouples. Directly proportional to temperature for Pt100.

Loop supply

12-36V dc; reverse connection protected.

Accuracy

Thermocouple ranges ±0.2% of span (linear to mV input)
Pt100 ranges ±0.1% of span (linear to temperature input)

Zero drift

±0.02% of span per °C

Span drift

±0.02% of span per °C

Supply voltage effect

±0.03% change of span over 12 to 36 voltage change

Cold junction

Better than 2°C over ambient

compensation

temperature range of 0 to 50°C; rejection ratio better than 25:1

Sensor open circuit detection & indication

Upscale; output current between 23 and 27 mA. Separate, independent alarms should be used if required for process safety.

Load capability

(Vs –12)/0.02 Ohm; Vs = 12 to 36Vdc

Ambient operating Temperature

0 to 70 °C

Storage temperature

-20 to 100 °C

Zero adjustment potentiometer 
±20% of span, 25 turns Span adjustment potentiometer down to 50% of span for thermocouple input and 30% of Span for PRT100 input, 25 turns. The transmitter can be easily ranged and calibrated by means of the multi-turn zero and span adjusters in conjunction with either a mV source or standard resistance input. For example, a type K-thermocouple which has a working temperature range of 0 to 1100°C can be easily calibrated to operate between 0 to 600°C, where 4mA and 20mA represent 0 and 600°C respectively.

Mechanical

Head mounting, dia.42mm, height 32mm, 2 mounting holes 32mm between centres