Research on the design method of the calibrator based on the electromagnetic flowmeter signal converter

The calibrator of the electromagnetic flowmeter signal converter is a device for testing and calibrating the performance of the electromagnetic flowmeter signal converter. The existing electromagnetic flowmeter signal converter is composed of a series of high-precision resistor networks, which can generally only perform fixed-point testing and calibration. The parameters such as the amplification factor of the converters of different manufacturers are different. Therefore, such a calibrator of the electromagnetic flowmeter signal converter can only perform fixed-point testing and calibration on a specific electromagnetic flowmeter signal converter without monitoring conditions. This limits the application of electromagnetic flowmeters.

Design ideas

The designed electromagnetic flowmeter signal converter calibrator includes an external electromagnetic flowmeter signal converter to be calibrated and a resistor network that outputs a fluid flow rate signal to be measured by the simulated electromagnetic flowmeter. The excitation current output by the electromagnetic flowmeter signal converter is used to provide power and synchronization signals to obtain the output signal of the simulated electromagnetic flowmeter sensor. The relative size of the analog signal can be adjusted and measured steplessly; and the output signal can be adjusted according to different types of converters, and different flow rate signals and different fluid impedances can be simulated. The relative amplitude of the output signal can be measured by an ordinary digital voltmeter, which can be used to calibrate electromagnetic flowmeter signal converter products from different manufacturers.

Implementation

The present design includes an external electromagnetic flowmeter signal converter to be calibrated and a resistor network that outputs a fluid flow rate signal to be measured by the simulated electromagnetic flowmeter. The excitation current output of the external electromagnetic flowmeter signal converter is connected to the primary input of a transformer via a bidirectional regulator, and the secondary output of the transformer is connected to the input of the resistor network. The output of the resistor network is connected to the input of a freewheeling circuit and the input of a constant current source appliance after passing through a full-wave rectifier, and the output of the constant current source circuit is connected to a sampling resistor; the resistor network simultaneously outputs the fluid flow rate signal to be measured by the simulated electromagnetic flowmeter and is connected to the signal input of the external electromagnetic flowmeter signal converter.