System to detect poor process ground connections

A magnetic flow meter for measuring a flow rate of a fluid in a pipe, the flow meter comprising:

• a flow tube adapted to couple to a pipe to carry a fluid;
• a magnetic coil disposed adjacent to the flow tube to induce an electromagnetic force (EMF) within the fluid;
• at least two electrodes disposed within the pipe, the at least two electrodes being electrically isolated from the flowtube and one another;
• measurement circuitry coupled to the at least two electrodes and adapted to measure flow rate based on the induced EMF;
• and
• diagnostic circuitry coupled to the at least two electrodes to monitor a common mode signal and adapted to detect a poor electrical ground connection when line noise associated with the common mode signal exceeds a noise threshold.

A magnetic flow meter comprising:

• a flow tube coupled to a pipe and adapted to carry a process fluid;
• first and second electrodes extending into the flow tube and coupled to the process fluid;
• and
• a diagnostic circuit coupled to the first and second electrodes to monitor a common mode signal between the first and second electrodes, the diagnostic circuit adapted to detect a poor electrical ground connection associated with at least one of the first and second electrodes when common mode line noise associated with the common mode signal exceeds a noise threshold.