Working principle and characteristics of on-site display integrated temperature transmitter

Integrated explosion-proof thermistor features: two-wire output 4-20mA, strong anti-interference ability; Save the cost of compensating wires and installing temperature transmitters; Safe and reliable, with a long service life; Cold end temperature automatic compensation, non-linear correction circuit;
Working principle of integrated explosion-proof thermistor
The change in thermoelectric potential (resistance) measured during operation generates an unbalanced signal through the bridge of the temperature transmitter, which is amplified and converted into a 4-20mA electrical signal for the working instrument to display the corresponding temperature value.
Explosion proof thermocouple (resistor) utilizes the principle of gap explosion-proof. When an explosion occurs inside the chamber, it can extinguish and cool through the gap between the joint surfaces, preventing the flame and temperature after the explosion from being transmitted outside the chamber, thus enabling temperature measurement. The thermoelectric potential (resistance value) generated by the thermocouple (resistor) is amplified by the temperature transmitter's bridge to generate an unbalanced signal, which is then converted into a 4-20mA DC electrical signal and sent to the worker's instrument. The working instrument displays the corresponding temperature value.
Main technical parameters of integrated explosion-proof thermistor
Product execution standards
IEC584
IEC751
IEC1515
JB/T5518-91
JB/T7391-94
Measurement range and tolerance of integrated explosion-proof thermistor
1) Temperature measurement range and tolerance of thermistor

model

Dividing number

Temperature measurement range ℃

Accuracy level

Allowable deviation

WZPB

Pt100

-200-+500

*Grade B

±(0.15+0.002ItI)

±(0.30+0.005 ItI)

WZCB

Cu50 Cu100

-50-+100

±(0.30+0.005 ItI)

Output signal: 4-20 mA, load resistance 250, transmission wire resistance 100
Output method: Two line system
Temperature transmitter accuracy level: 0.1 0.2 0.5
Display accuracy level: Analog indicator 2.5 level; Digital display level 0.5
Power supply: 24V DC±10℅
Protection level: IP65
Explosion proof grade:
Explosion proof type: d Ⅱ BT4 d Ⅱ CT5 d Ⅱ CT6
Intrinsic safety type: ia Ⅱ CT6
Insulation resistance: The insulation resistance between the instrument output terminal and the housing should not be less than 50
Thermal response time:
When there is a step change in temperature, the time required for the current output signal of the instrument to change to 50% of the step change is usually represented by t0.5. When the step response stabilization time of the temperature transmitter does not exceed one-fifth of the thermocouple (resistance) thermal response stabilization time t0.5, the thermocouple (resistance) thermal response time is used as the thermal response time of the instrument; When the step thermal response stability time of the temperature transmitter does not exceed half of the thermocouple (resistance) thermal response stability time t0.5, the thermal response time of the temperature transmitter is used as the thermal response time of the instrument;
Basic error:
The basic error of the instrument should not exceed the combined error of the basic errors of the thermocouple (resistor) and temperature transmitter.