product overview

Integrated digital temperature transmitter is an instrument that converts industrial thermocouple and thermistor signals into standard output signals. It adopts a two-wire transmission method and can be directly installed in the junction box of thermocouples and thermocouples. It has the characteristics of shock resistance, moisture resistance, and strong anti-interference ability, and is widely used in metallurgy, petroleum, chemical and other fields.

The SBWR and SBWZ series thermocouples and thermal resistance temperature transmitters are on-site installed temperature transmitter units in the DDZ series instruments, used in conjunction with industrial thermocouples and thermal resistance. It adopts a two-wire transmission method (two wires serve as a common transmission line for power input and signal output). Convert industrial thermocouple and thermistor signals into 4-20mA and 0-10mA output signals that are linear with the input signal or temperature signal.

This temperature transmitter can be directly installed in the junction box of thermocouples and thermal resistors to form an integrated structure. As a new generation of temperature measuring instrument, it can be applied in various industrial sectors such as metallurgy, petroleum, chemical, power, light industry, textile, food, national defense, and scientific research.

main features

1. Adopting silicone rubber or epoxy resin sealing structure, it is shock resistant, moisture resistant, and suitable for installation and use in harsh on-site environments.

2. Installed on-site in junction boxes for thermocouples and thermal resistors, directly outputting 4-20mA and 0-10mA output signals. This not only saves expensive compensation wire costs, but also improves the anti-interference ability during long-distance signal transmission;

3. The thermocouple transmitter has an automatic compensation function for cold junction temperature;

4. High precision, low power consumption, wide temperature range for use, stable and reliable operation;

5. Widely applicable, it can form an integrated on-site installation structure with thermocouples and thermistors, and can also be installed as a functional module in detection equipment and instrument panels for use;

6. The intelligent temperature transmitter can communicate with the upper computer through a HART modem or remotely manage, configure, monitor variables, calibrate, and maintain the model, scale, and range of the transmitter through handheld devices and PCs;

7. The intelligent temperature transmitter can adjust the display direction of the transmitter according to the actual needs of the user, and display the medium temperature measured by the transmitter, changes in sensor values, output current, and percentage.

Working principle

Thermocouples or thermal resistance sensors convert the measured temperature into electrical signals, which are then sent to the input network of the transmitter. This network includes relevant circuits such as zeroing and thermocouple compensation. The zero adjusted signal is input to an operational amplifier for signal amplification. The amplified signal is then processed by a V/I converter and output as a 4-20mA DC current; The other path is processed by an A/D converter and displayed in the header. There are two types of linearization circuits for transmitters, both of which use feedback methods. For thermistor sensors, calibrate using positive feedback method, and for thermocouple sensors, calibrate using multi segment line approximation method. The integrated digital display temperature transmitter has two display modes. The temperature transmitter for LCD display outputs in a two-wire system, while the temperature transmitter for LED display outputs in a three wire system.

Technical Parameter

1. Input signal: Thermocouples: K, E, J, B, S, T, N. Thermal resistance: Pt100, Cu50, Cu100 (three wire system, four wire system). The input signal of the intelligent temperature transmitter can be set arbitrarily through a handheld device and a PC;

2. Output signal: Output a 4-20mA DC signal within the range of measurement, which is linear with the input signal of the thermocouple or thermistor or linear with temperature. The intelligent temperature transmitter outputs a 4-20mA DC signal and superimposes it with communication in accordance with the HART standard protocol; Isolated temperature transmitter: Input and output are isolated, with an isolation voltage of 500V, which increases the ability to resist common mode interference and is more suitable for networking with computers;

3. Basic error: 0.5% FS, 0.2% FS, intelligent 0.2% FS;

4. Wiring methods: two-wire system, three wire system, four wire system;

5. Display mode: Four digit LCD displays the on-site temperature, and the intelligent four digit LCD can be set through a PC or handheld device to display any of the parameters such as on-site temperature, sensor value, output current, and percentage;

6. Working voltage: Ordinary model 12V-35V, intelligent model 12V-45V, rated working voltage is 24V

7. Allowable load resistance: 500 Ω (24VDC power supply); The maximum load resistance R (max) is 50 (Vmin-12). For example, at a rated operating voltage of 24V, the load resistance can be selected and used within the range of 0-600 Ω.

8. Working environment: a: ambient temperature -25-+80 ℃ (conventional type)

-25-+70 ℃ (digital display type)

-25+75 ℃ (intelligent type)

b: Relative humidity: 5% -95%

c: Mechanical vibration f ≤ 50Hz, amplitude ≤ 0.15mm

d: No corrosive gas or similar environment;

9. Environmental impact coefficient: δ ≤ 0.05%/℃.

measuring range

thermocouple

Nickel chromium constantan E can be selected within the temperature range of 0-1000 ℃

Nickel chromium nickel silicon K can be selected within the temperature range of 0-1300 ℃

Platinum rhodium 10 Platinum S can be selected within the temperature range of 0-1600 ℃

Platinum rhodium 30- Platinum rhodium 6 B, optional within the temperature range of 0-1800 ℃

Copper constantan T can be selected within the temperature range of 0-400 ℃

Iron constantan J can be selected within the temperature range of 0-1200 ℃

thermal resistance

Copper thermistor can be selected within the temperature range of Cu50-50-+150 ℃

Copper thermistor Cu100-50-+15 ℃ range, optional

Platinum resistance thermometer Pt100-200-+600 ℃, optional

Outline and structural diagram: