MultiTrak™ 670S


Sierra's MultiTrak™ 670S is an advanced state-of-the-art instrument for measuring mass flow rates in very large ducts or stacks that have non-uniform velocity profiles, high turn-down requirements, dirty gas streams, wide temperature ranges and fast velocity and temperature changes. The MultiTrak™ dynamically compensates for changes in the flow profile by using up to four independent mass flow sensing points to measure the instantaneous average gas mass flow velocity. The MultiTrak™ is commonly used in petrochemical refining, coal-fired electric power generation, steel manufacturing and many other industrial processes that face the challenge of accurate and repeatable gas mass flow measurement in very large pipes or ducts.


  • The standard 670S system consists of up to four sensing points linked via Modbus, one control box with touch-screen HMI and a 4-20mA output module with the associated cables (power, 4-20mA output cable for daisy-chaining all sensing points).
  • Innovative and user-friendly HMI offers advances over industry-standard collector boxes and allows users to:
  • Average the flow of 4 meters
  • Convert flow units
  • Set up the density of the gas for mass flow measurement
  • Easily configure the individual meters
  • Set up alarms
  • Unique multiple transmitter approach allows individual points to be removed for service or repair without shutting down the system
  • Direct mass flow monitoring eliminates the need for separate temperature and pressure inputs
  • Accuracy +/- 1 % of reading plus 0.5% of full scale
  • Patented Dry-Sense™ technology eliminates sensor drift
  • State-of-the-art calibration facility ensures a highly accurate calibration that matches the application
  • High temperature option to 750ºF (400ºC) available
  • Low pressure hot taps available
 MultiTrak™ 670S