Back To Top
Rosemount™ 644 Temperature Transmitter
Engineered for versatility, the Rosemount 644 Temperature Transmitter is available with HART™, FOUNDATION™ Fieldbus or PROFIBUS™ protocols in head, field 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.
Rosemount™ 644 Temperature Transmitter


Dual and single sensor capability with universal sensor inputs (RTD, T/C, mV, ohms)
Output Signal
4-20 mA /HART™ protocol, FOUNDATION™ fieldbus protocol, PROFIBUS™ PA protocol
Field mount, DIN A head mount or rail mount
LCD Display, LCD Display with Local Operator Interface (LOI), or LED
Basic diagnostics, Hot Backup™ capability, sensor drift alert, thermocouple degradation, min/max tracking
Calibration Options
Transmitter-sensor matching (Callendar-Van Dusen constants), 5-point calibration
SIL 2/3 certified to IEC 61508 by an independent 3rd party, hazardous location, marine type, see full specs for complete list of certifications


  • Extremely versatile temperature transmitter available in HART™, FOUNDATION™ Fieldbus or PROFIBUS™ protocols
  • Diverse mounting configurations including head, field 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
  • Minimum and maximum temperature tracking observes temperature extremes for easy troubleshooting
  • Device dashboards provide easy interface for simplified device configuration and diagnostic troubleshooting