Process meter

Abstract

The process meter serves for the measurement of a physical process parameter of a medium contained in a process vessel or flowing in a process line and comprises a meter probe (10), with a sensor arrangement (60), providing measured signals (s1, s2) and a meter electronics device (50), connected to the meter probe (10). The sensor arrangement (60) comprises a primary sensor element (17), reacting to the physical process parameter, also in particular, changes in the physical process parameter and provides a measured signal (s1), dependent on the physical process parameter. The sensor arrangement (60) further comprises at least one temperature sensor (40), arranged in the meter probe (10), which records a local temperature (T1) in the meter probe (10) and provides the sensor arrangement (60) with a measured temperature signal (theta1) which represents the temperature (T1) in the meter probe (10). The meter electronics device (50) generates an instantaneous measured value (X), representing the physical parameter, using the measured signal (s1) and using a correction value (K1) for the measured signal (s1). The meter electronics device (50) determines said correction value (K1), by means of the curve with time of the one measured temperature signal (theta1), such as to take account of the temperature values recorded by the temperature sensor (40) in the past. According to the invention, temperature generated errors in the measured signal are well compensated by said process meter, even with a fluctuating transition range for the temperature distribution within the meter probe and particularly with the application of only a few temperature sensors.

Description

technical field [0001] The invention relates to a process measuring device for measuring at least one physical process variable, in particular mass flow, density, viscosity, pressure, etc., contained in a process vessel or flowing in a process line. Background technique [0002] In industrial process measurement technology, especially with regard to chemical automation or other industrial processes, process measuring instruments installed on site (ie close to the site), so-called field measuring instruments, are used to generate analog or digital measurements representing process quantities. Examples of such process measuring instruments are well known to those skilled in the art from EP-A 984 248, EP-A 1 158 289, US-A 3,878,725, US-A 4,308,754, US-A 4,468,971, US-A 4,524,610 , US-A4,574,328, US-A 4,594,584, US-A 4,617,607, US-A 4,716,770, US-A4,768,384, US-A 4,850,213, US-A 5,052,230, US-A 5,131,279, US-A5,231,884, US-A -A 5,359,881, US-A 5,363,341, US-A 5,469,748, US-A5,6...

AI Technical Summary

Problems solved by technology

[0027] A disadvantage of this solution is that as the number of temperature sensors used increases, so does the manufacturing cost

In addition to the cost of the temperature sensors themselves, their installation and wiring costs add

[0028] In addition, however, an increase in the number of temperature sensors leads to an increased probability of failure of the sensor arrangement, especially if the temperature sensors are fixed to components that vibrate at high frequencies, e.g. to the measuring tube or as support elements for vibration isolator designs

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