How to choose a temperature transmitter

1. Overview:

The SWBR and SWBZ series thermocouple and RTD temperature transmitters are field-mountable temperature transmitter units in the DDZ series of instruments. They are used with industrial thermocouples and RTDs. They utilize a two-wire transmission system (two wires serve as a common transmission line for power input and signal output). They convert industrial thermocouple and RTD signals into 4-20mA and 0-10mA output signals that are linear with the input signal or temperature signal.

2. Key Features:

• Silicone rubber or epoxy resin sealing ensures vibration and moisture resistance, making them suitable for installation in harsh field environments.

• Field-mounted in the junction box of a thermocouple or RTD, they directly output 4-20mA and 0-10mA signals. This not only saves expensive compensation wires but also improves signal interference immunity during long-distance transmission.

· Thermocouple transmitters feature automatic cold-junction temperature compensation.

· High accuracy, low power consumption, a wide operating temperature range, and stable and reliable operation.

· Widely applicable, they can be integrated with thermocouples and RTDs for field installation or installed as functional modules in testing equipment and instrument panels.

3. Operating Principle:

Thermocouple or RTD sensors convert the measured temperature into an electrical signal, which is then fed into the transmitter's input network, which includes circuits for zero adjustment and thermocouple compensation. The zero-adjusted signal is then input to an operational amplifier for amplification. One path of the amplified signal is 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 on the meter. The transmitter has two linearization circuits, both employing feedback. For RTD sensors, positive feedback is used for calibration, while for thermocouple sensors, a multi-segment broken line approximation is used. The integrated digital display temperature transmitter offers two display modes. The LCD display uses a two-wire output, while the LED display uses a three-wire output.

4. Technical Parameters

1. Input Signal: Thermocouples: K, E, J, B, S, T, N. RTDs: Pt100, Cu50, Cu100 (three-wire and four-wire). The input signal of the intelligent temperature transmitter can be freely configured via a handheld device or PC.

2. Output Signal: A 4-20mA DC signal is output within the measuring range, linear with the thermocouple or RTD input signal or with temperature. The intelligent temperature transmitter outputs a 4-20mA DC signal and simultaneously superimposes HART-compliant communication. The isolated temperature transmitter features 500V isolation between input and output, providing increased immunity to common-mode interference and making it suitable for computer networking.

3. Basic Error: 0.5% FS, 0.2% FS, 0.2% FS for the intelligent model.

4. Wiring: Two-wire, three-wire, or four-wire.

5. Display: A four-digit LCD displays the local temperature. The intelligent four-digit LCD can be configured via a PC or handheld device to display any of the following parameters: local temperature, sensor value, output current, and percentage.

6. Operating Voltage: 12V-35V for standard models, 12V-45V for intelligent models. Rated operating voltage is 24V.

7. Allowable Load Resistance: 500Ω (24VDC power supply); Maximum Load Resistance R(max) = 50Vmin-12. For example, at a rated operating voltage of 24V, the load resistance can range from 0 to 600Ω.

Guide-Rail Temperature Transmitter

1. Applications:

Guide-Rail Temperature Transmitters utilize advanced digital technology and possess numerous advanced features not found in traditional analog instruments. They excel in suppressing both high- and low-frequency interference signals and can be used with modular instruments, DCS systems, PLCs, and other systems. They are widely used in industries such as oilfields, petrochemicals, manufacturing, power generation, and metallurgy.
2. Technical Specifications:
1. Input: Thermocouples K, E, S, B, J, R, N; Thermocouples PT100, Cu50, BA1, BA2, Cu100, etc.
2. Accuracy: ±0.5% × FS (±0.2% × FS for special applications)
3. Temperature Drift: ≤0.0015% FS/°C
4. Cold Junction Compensation Accuracy: ±0.1%
5. Allowable Lead Resistance for RTD Input: ≤50Ω
6. Operating Temperature: Industrial Standard -10°C to +60°C

3. Features:
1. This rail-mounted temperature transmitter utilizes a highly integrated single-chip microcontroller, offering high integration, high accuracy, high linearity, strong anti-interference capabilities, and simple adjustment and calibration. It possesses several advanced features not found in traditional analog temperature transmitters and many digital temperature transmitters. The intelligent chip provides software-based suppression and processing of high- and low-frequency interference signals in the input signal. It maintains reliable performance even in high-power variable-frequency control systems. The instrument allows for digital automatic/manual signal calibration without the need for external zero and span potentiometers. It also automatically compensates the input signal.
2. This temperature transmitter can also be connected to the JCBC-1001 operator panel via communications for online monitoring of input and output values. In addition to its common functions, this integrated intelligent temperature transmitter also supports signal logic processing and the ability to set alarm outputs based on input status, revolutionizing the functionality of the temperature transmitter and broadening its application range.
3. The powerful software capabilities of the DIN-rail temperature transmitter and the excellent electrical performance of the temperature transmitter itself provide a solid guarantee for product stability and reliability, ensuring its overall performance is at the forefront of international standards.
4. This temperature transmitter can be used with unit combination instruments, DCS, PLC, and other systems, making it widely applicable in complex industrial control environments such as oilfields, petrochemicals, power generation, manufacturing, metallurgy, and pharmaceuticals.