Digital flowmeter

摘要

A control and measurement system for a coriolis flowmeter having a flowtube, a driver adapted to vibrate the flowtube, and a pair of sensors adapted to generate signals indicative of movement of the flowtube when it is being vibrated by the driver, wherein the sensors are positioned relative to one another so the signals from the sensors are indicative of a mass flow rate of fluid through the flowtube. A digital drive signal generator is adapted to generate a variable digital drive signal for controlling operation of the driver. The digital drive signal generator can be adapted to cause the driver to resist motion of the flowtube during a first time period and amplify motion of the flowtube during a second time period. The digital drive signal generator can also be adapted to initiate motion of the flowtube by sending one or more square wave signals to the driver.

主权项

1. A control and measurement system for a Coriolis flowmeter of the type comprising a flow tube, a driver configured to oscillate the flow tube, and a pair of sensors configured to generate signals indicative of movement of the flowtube when it is being oscillated by the driver, the sensors being positioned relative to one another so the signals from the sensors are indicative of a mass flow rate of fluid through the flowtube, the control and measurement system comprising:
a digital signal processor configured to determine the mass flow rate of the fluid using the sensor signals and output a signal indicative of the determined mass flow rate; and a digital drive signal generator configured to generate a variable drive signal for controlling operation of the driver; wherein the drive signal generator is configured to digitally generate a gain based on the sensor signals for use generating the drive signal; and wherein the drive signal generator is configured to selectively apply a negative gain to reduce motion of the flowtube.