How it works
Temperature transmitters are a key link in industrial temperature measurement. Their main function is to precisely convert, adjust and standardize the output of the original, weak and nonlinear electrical signals detected by temperature sensors (such as thermocouples and thermal resistors). Signal conversion and conditioning: It first amplifies weak signals and performs linearization processing (making the output signal proportional to the temperature). For thermocouples, cold junction compensation is also required to eliminate the influence of ambient temperature and filter out interference. Standardized output: Convert the processed signal into a standard signal commonly used in industry. The most frequently used ones are 4-20mA DC current signals with strong anti-interference ability (a few are 0-10V, etc.), or digital signals (such as HART). Reliable transmission: Standard signals (especially 4-20mA) are suitable for long-distance transmission and have strong anti-interference ability. Its "two-wire" design simplifies wiring (power supply and signal transmission on the same pair of wires), and can directly drive display instruments or input control systems. Electrical isolation: Usually, electrical isolation is provided to prevent interference and ensure system safety.
Key features
• Extremely versatile temperature transmitter available in HART™, FOUNDATION™ Fieldbus or PROFIBUS™ protocols
Diverse mounting configurations including head or rail mount with many enclosure options
LOI option eliminates the need for special configuration tools (i.e. field communicator) for ease-of-use
Transmitter-sensor matching with Callendar-Van Dusen constants reduces total measurement error
Hot Backup™ capability and sensor drift alert with dual sensors ensure measurement integrity
Thermocouple degradation diagnostic monitors thermocouple health to detect degradation before failure
Typical applications
Rosemount™ 644 Temperature Transmitter
This versatile, industry standard transmitter is available in head, field or rail mount styles and a variety of enclosure options.
Engineered for versatility, the Rosemount 644 Temperature Transmitter is available with HART™, FOUNDATION™ Fieldbus or PROFIBUS™ protocols in head or rail mount styles and a variety of enclosure options. By adding a Local Operator Interface (LOI), you can update your transmitter configuration in the field without tools. For diverse application requirements, this transmitter includes diagnostic capabilities, such as Hot Backup™ Capability, Sensor Drift Alert and Thermocouple Degradation.
