Mass flowmeter with low-cost circuitry - has field coil current regulation amplifier with density transducer signal input

摘要

The mass flowmeter has a density measurement device, a magnetoinductive flowmeter and transducer and a power supply for the transducer field coil. It provides accurate measurement results using low-cost circuitry. The transducer contains a field coil (14) current regulation and time control (18) device. The regulation and control device contains a control element (20) whose control input is driven by a control amplifier (25) and which is connected to one input of the control amplifier via a differential amplifier (24). A resistor (30) is connected to the other input of the control amplifier (25). The density proportional output of the density measurement device (33) is connected across the resistor (30) which converts the current proportional to density into a regulation amplifier voltage input. The resistor (30) may be replaced by a potentiometer and constant voltage source.