Digital display integration PT100 temperature transmitter is introduced

A thermometer, digital integration overview:

thermometer digital display integration and industrial thermocouple, heat resistance, the integration of digital display temperature transmitter using two wire transmission mode ( Two wire as the power input and output signals of the public line), 。 Integrated temperature transmitter converts industrial thermocouple, thermal resistance signal and the input signal is 4 - or with the temperature signal into a linear 20mA、0- 10 ma, the output of the signal. Integrated digital display can be directly installed in the thermocouple temperature transmitter, thermal resistance terminal box and the formation of integration of the structure. It as a new generation of thermometer table can be widely applied to metallurgy, petroleum, chemical, power, light industry, textile, food, national defense and scientific research and other industrial sectors. Integrated temperature transmitter is the perfect combination of thermocouple temperature sensor and transmitter, the - in very simple way 200 ~ + 1600 ℃ temperature in the range of the signal is converted to a two wire 4 ~ 20 ma DC electrical signal transmission to display, regulator, recorder, DCS, etc. , it can realize accurate measurement and control of temperature. Integrated temperature transmitter is the modern industrial field, the update products, scientific research institutes temperature measurement and control is necessary for collecting and distributing system, digital bus system. :

2, the working principle of the integration of digital display thermometer:

1, general by the reference source of temperature transmitter, cold junction compensation, amplification, linearization, VI conversion unit, broken accidentally processing, reverse connect protection, current limiting circuit protection units. It is the cold junction compensation of thermocouple thermoelectric potential enlarged, cap again by linear circuits eliminate the nonlinear error of thermoelectric potential and temperature, the final amplification into 4 ~ 20 ma current output signal. In order to prevent the thermocouple measurement by thermocouple wire break and make the temperature control failure caused by accident, transmitter will also include a power protection circuit. When the thermocouple wire break or pick up solution, transmitter will output the maximum value ( 28mA) In order to make the instrument to cut off the power supply.

2, the thermocouple or heat resistance thermocouple sensors measured temperature will be converted into electrical signals, then send the signals to the input of the network in the transmitter, the network contains zero and thermocouple compensating circuit. After zero input signals to the operational amplifier for signal amplification, the amplification of a signal path VI converter with 4 - after processing 20 ma dc current output; After another through the AD converter processing to display meter. There are two kinds of the linearization of the transmitter circuit, adopt feedback way. On the thermal resistance, thermocouple sensor correction with positive feedback way, the thermocouple, thermocouple sensor with multiple line approximation method for correction. There are two kinds of integrated digital display temperature transmitter display mode. LCD display of the temperature transmitter with two wire system output, the temperature of the LED display transmitter output in three wire system mode.

3, integrated temperature transmitter by temperature measuring probe (commonly The thermocouple or heat resistance thermocouple sensor) And the two wire system solid electronic units. In the form of solid module temperature measuring probe directly installed on the terminal box, thus forming the integration of the transducer. Integrated temperature transmitter with thermal resistance and thermocouple generally fall into two types. Heat resistance temperature transmitter is the RV conversion unit, linear circuit unit, the benchmark, reverse connect protection, current limiting protection, VI conversion unit, etc. Measuring temperature resistance signal amplification, and then by linear circuit of temperature compensate nonlinear relationship with the resistance, after VI conversion circuit outputs a measured a linear relationship with temperature and constant current signal of 4 ~ 20 ma.

3, the integration of digital display thermometer function characteristics:

1, the integration of digital display temperature transmitter using silicone rubber and epoxy resin sealing structure, so the seismic, moisture resistance, suitable for installation at the scene of the harsh environment.

2, on-site installation in the terminal box use of thermocouple, heat resistance, 4 - direct output 20mA、0- 10 ma, the output of the signal. This saves the expensive. Compensation conductor should be cost, and improve the anti-interference ability in the process of signal transmission over a long distance;

3, thermocouple transmitter has cold end temperature automatic compensation function;

4, high precision, low power consumption, use of wide temperature range, stable and reliable work;

5, the integration of digital display temperature transmitter wide applicable scope, can form integrated installation structure with thermocouple, heat resistance, can also be used as a functional modules installed on the testing equipment and instrument panel use;

6, can pass HART communication or handheld device with a modem and the upper machine and PC to the transmitter model, index number, range. For remote information management, configuration, variables, monitoring, calibration, and maintenance functions;

7, according to user's actual need to adjust the transducer according to direction, and display the measured medium temperature transmitter, the thermocouple sensor values change, the output current and percentage rate;