Temperature Transmitter - JDTH

Temperature Transmitter

Application

It is usually connected with display meter, recording meter and computer, etc. to directly measure temperature of liquid, vapor, gas and solid surface ranging from 0 c to 1800 c with output of 4~20mA.

Features

1. Double wire system output of 4~20mA,good anti-interference performance;

2. Spare cost on compensational wire and temperature transmitter installation;

3. Wide measuring range;

4. Automatic compensation at cold end ,non-linear rectifying circuit.

Operation Theory

Pryoelectric potential change tested with the thermocouple (thermal resistance) results in imbalance signal through electrical bridge of temperature transmitter. The signal transforms into D.C. 4~20mA signal after being amplified and is transmitted to working meter, then working meter shows relevant temperature value.

Main Technical Parameters

Executive Standard

IEC 584 IEC 751 JB/T7391-1994

Output Signal:

4~20mA Loading Resistance: 2501/2,Transmission Conductor Resistance: 1001/2

Output Way:

Double Wire System

Tolerance Class:0.1;0.2;0.5

Power Supply:24V.DC+-10%

Protection Class:IP65

Insulation Resistance:

Insulation resistance between wiring terminal and outer shell of the instrument shall be no less than 501/2.

Thermal Response Time:

We use 0.5 to represent the time needed for current output signal of instrument to change to 50% of step change of temperature.

When step response time of temperature transmitter is no more than 1/5 of thermal response time 0.5 of thermocouple(thermal resistance),thermal response time of thermocouple (thermal resistance) is considered as that of the instrument .

When step response time of temperature transmitter is no more than 1/2 of thermal response time 0.5 of thermocouple (thermal resistance),thermal response time of temperature transmitter is considered as than of the instrument.

Basic Error:

The basic error shall be no more than total error of thermocouple and temperature transmitter.

Support Tube Length:

Operation temperature of temperature transmitter is the sum of shell temperature rise caused by support tube and ambient temperature. PLS see the following figure for shell temperature rise caused by support tube.