Abstract: A magnetic flow meter for measuring flow of a process fluid in a pipe, the flow meter includes a magnetic coil disposed adjacent to the pipe configured to apply a magnetic field to the process fluid. First and second electrodes disposed within the pipe which are electrically coupled to the process fluid and configured to sense an electromotive force (EMF) induced in the process fluid due to the applied magnetic field and flow of the process fluid and responsively provide respective first and second electrode signals. Output circuitry coupled to the first and second electrodes provides an output related to the sensed EMF. Diagnostic circuitry provides an electrode referenced diagnostic signal. A method is also provided.

Abstract: A magnetic flowmeter includes a flow tube assembly, an electromotive force (EMF) sensor, a power amplifier, a current sampling circuit, and a controller. The flow tube assembly receives the fluid flow, and includes a coil configured to receive a coil current and induce an EMF in the fluid flow that is proportional to the flow rate. The EMF sensor generates an output indicating the induced EMF. The power amplifier is configured to generate unfiltered current pulses at a first frequency. The power amplifier includes a low pass filter that attenuates the unfiltered current pulses to form coil current pulses at a second frequency that form the coil current. The current sampling circuit samples the coil current pulses at a sampling frequency. The controller is configured to change a relationship between the sampling frequency and the first frequency, and adjust the coil current based on the samples.

Abstract: A magnetic flowmeter includes a flow tube assembly, an electromotive force (EMF) sensor, a power amplifier, a current sampling circuit, and a controller. The flow tube assembly receives the fluid flow, and includes a coil configured to receive a coil current and induce an EMF in the fluid flow that is proportional to the flow rate. The EMF sensor generates an output indicating the induced EMF. The power amplifier is configured to generate unfiltered current pulses at a first frequency. The power amplifier includes a low pass filter that attenuates the unfiltered current pulses to form coil current pulses at a second frequency that form the coil current. The current sampling circuit samples the coil current pulses at a sampling frequency. The controller is configured to change a relationship between the sampling frequency and the first frequency, and adjust the coil current based on the samples.

Abstract: A magnetic flow meter includes electrode sensors generating a sensor signal indicative of flow of a liquid through a conduit. A noise identification module identifies a noise level in the sensor signal and a contaminant identification module uses the noise level to determine whether there is a contaminant in the liquid in the conduit.

Abstract: A magnetic flowmeter includes circuitry for sensing coil current, coil voltage, or coil resistance. Based on the sensed coil current, voltage, or resistance, a digital processor determines whether a power limit or a coil current limit is exceeded and either halts operation until it receives a new configuration with a new coil current setpoint, or determines a new coil current setpoint itself and adjusts the magnetic flowmeter to that new coil current setpoint.

Abstract: A magnetic flowmeter includes a flowtube with electrodes and field coil and a transmitter that automatically determines an operating setpoint for the magnetic flowmeter based upon sensed coil inductance, sensed coil resistance, a power rating for the transmitter, the flowtube, or both, and selected performance criteria.

Abstract: A magnetic flow meter includes electrode sensors generating a sensor signal indicative of flow of a liquid through a conduit. A noise identification module identifies a noise level in the sensor signal and a contaminant identification module uses the noise level to determine whether there is a contaminant in the liquid in the conduit.

Abstract: A magnetic flowmeter for measuring flow of a process fluid in a pipe includes a magnetic coil disposed adjacent to the pipe configured to apply a magnetic field to the process fluid. First and second electrodes are disposed within the pipe and electrically coupled to the process fluid and configured to sense an electromotive force (EMF) induced in the process fluid due to the applied magnetic field and flow of the process fluid. Input circuitry is coupled to the first and second electrodes and provides an output related to the sensed EMF. Diagnostic circuitry coupled to the input circuitry is configured to identify a saturation related condition and responsively provide a diagnostic output. In another embodiment, saturation prevention circuitry prevents saturation of the input circuitry.

Abstract: A magnetic flowmeter comprises a pipe section for process flow, a coil for generating a magnetic field across the pipe section, a current source for energizing the coil to generate the magnetic field at a coil drive frequency, and electrodes for sensing voltage induced across the process flow by the magnetic field. A processor calculates a function of the sensed voltage and generates a flow output based on the function. The processor adjusts an operating parameter of the flowmeter, such as electrode voltage sampling period, the coil drive frequency, or a phase shift, as a function of a sensed electrode-to-electrode or electrode-to-ground complex impedance.

Abstract: A magnetic flowmeter for measuring flow of a process fluid in a pipe includes a magnetic coil disposed adjacent to the pipe configured to apply a magnetic field to the process fluid. First and second electrodes are disposed within the pipe and electrically coupled to the process fluid and configured to sense an electromotive force (EMF) induced in the process fluid due to the applied magnetic field and flow of the process fluid. Input circuitry is coupled to the first and second electrodes and provides an output related to the sensed EMF. Diagnostic circuitry coupled to the input circuitry is configured to identify a saturation related condition and responsively provide a diagnostic output. In another embodiment, saturation prevention circuitry prevents saturation of the input circuitry.

Abstract: A magnetic flowmeter for measuring flow of a process fluid in a pipe includes a magnetic coil disposed adjacent to the pipe configured to apply a magnetic field to the process fluid. First and second electrodes are disposed within the pipe and electrically coupled to the process fluid and configured to sense an electromotive force (EMF) induced in the process fluid due to the applied magnetic field and flow of the process fluid. Input circuitry is coupled to the first and second electrodes and provides an output related to the sensed EMF. Diagnostic circuitry coupled to the input circuitry is configured to identify a saturation related condition and responsively provide a diagnostic output. In another embodiment, saturation prevention circuitry prevents saturation of the input circuitry.

Abstract: A magnetic flowmeter includes a flowtube arranged to receive a flow of process fluid. A coil is positioned proximate the flowtube and arranged to apply a magnetic field to the process fluid in response to a drive current alternating direction. First and second electrodes are arranged to sense a voltage potential in the process fluid in response to the applied magnetic field. The voltage potential is indicative of flow rate of process fluid through the flowtube. A sensor is coupled to the first and second current paths which has a sensor output related to the drive current. Diagnostic circuitry provides a diagnostic output as a function of a transient change in the sensor output when current flowing through the coil alternates direction.

Abstract: A magnetic flowmeter includes a flowtube with electrodes and field coil and a transmitter that automatically determines an operating setpoint for the magnetic flowmeter based upon sensed coil inductance, sensed coil resistance, a power rating for the transmitter, the flowtube, or both, and selected performance criteria.

Abstract: A magnetic flowmeter for measuring flow of a process fluid in a pipe includes a magnetic coil disposed adjacent to the pipe configured to apply a magnetic field to the process fluid. First and second electrodes are disposed within the pipe and electrically coupled to the process fluid and configured to sense an electromotive force (EMF) induced in the process fluid due to the applied magnetic field and flow of the process fluid. Input circuitry is coupled to the first and second electrodes and provides an output related to the sensed EMF. Diagnostic circuitry coupled to the input circuitry is configured to identify a saturation related condition and responsively provide a diagnostic output. In another embodiment, saturation prevention circuitry prevents saturation of the input circuitry.

Abstract: A magnetic flowmeter includes a flowtube arranged to receive a flow of process fluid. A coil is positioned proximate the flowtube and arranged to apply a magnetic field to the process fluid in response to a drive current alternating direction. First and second electrodes are arranged to sense a voltage potential in the process fluid in response to the applied magnetic field. The voltage potential is indicative of flow rate of process fluid through the flowtube. A sensor is coupled to the first and second current paths which has a sensor output related to the drive current. Diagnostic circuitry provides a diagnostic output as a function of a transient change in the sensor output when current flowing through the coil alternates direction.

Abstract: A magnetic flowmeter includes circuitry for sensing coil current, coil voltage, or coil resistance. Based on the sensed coil current, voltage, or resistance, a digital processor determines whether a power limit or a coil current limit is exceeded and either halts operation until it receives a new configuration with a new coil current setpoint, or determines a new coil current setpoint itself and adjusts the magnetic flowmeter to that new coil current setpoint.

Abstract: A magnetic flowmeter comprises a pipe section for process flow, a coil for generating a magnetic field across the pipe section, a current source for energizing the coil to generate the magnetic field at a coil drive frequency, and electrodes for sensing voltage induced across the process flow by the magnetic field. A processor calculates a function of the sensed voltage and generates a flow output based on the function. The processor adjusts an operating parameter of the flowmeter, such as electrode voltage sampling period, the coil drive frequency, or a phase shift, as a function of a sensed electrode-to-electrode or electrode-to-ground complex impedance.