The sensor is equipped with IP68 protection structure. The converter is installed in the instrument box or indoor, and the two are connected by cables. Due to the changes of ground subsidence, mountainous environment moisture and other site conditions, the sensor and converter have not been thoroughly treated with moisture-proof (waterproof) treatment at the cable connection. When the connector is in a humid environment, such as instrument well, cable trench, etc., moisture intrusion into the cable connector may result in the following possibilities:

(1) The excitation coil is reduced to ground insulation, resulting in a small measurement result;

(2) The contact resistance at the cable connection of the excitation loop becomes larger, so that the converter's excitation loop is in the non-constant current working area and the excitation current drops, which also results in a small measurement result. If the contact resistance is unstable, the measured value will fluctuate.

(3) The insulation of the signal line to the ground drops, resulting in signal attenuation, which ultimately results in a small measurement result;

(4) The insulation performance of the excitation line of the signal line to the ground decreases, making the measured results far greater than the normal data. For example, such interference is unstable, and the influence on the hot-water flow sensor and instrument also varies, and then fluctuates;

(5) The contact resistance at the signal cable connection becomes larger, making the measured value smaller. If the contact resistance is unstable, the measured value cannot be stable and interference is easy to be introduced;

Anomalies due to occur in the above signal circuit, has the certain difficulty, only field, after rule out other circulating water flow sensor fault, you should check whether there is cable problem, field instrument maintenance personnel as long as the field excitation loop resistance measurements and data provided by the manufacturer, the test grounding resistance, step by step to determine the problem, then take measures, or replace the whole cable, or stay cable joint dry, etc.

Sewage flow sensor inside the rotor is more than a year, basically not failure, but a year later, will often appear abnormal work, specific performance for measuring value becomes large or small, or keep fluctuations, and through on-site inspection, has ruled out pipe discontent, medium the possibility of the phenomenon such as gas, found the problem may be related to cable fault likely also.