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The secondary display of the electric contact level gauge shows that all contacts are shaking or some of the contacts are shaking. Common causes of such problems include steam-water azeotropy inside the furnace, signal noise interference, interference due to the accumulation of capacitance in the signal lines, and unreliable grounding of the common lines. This post shares methods and approaches for dealing with these faults. Fault symptom: During operation, most or all of the electrical contact points at the water level frequently or occasionally vibrate. Electrical contact level gauge yunrun.com.cn/product/295.html Common causes: 1. Vapor-liquid azeotropy inside the furnace. Method of determination: Check whether other glass tube level gauges, dual-color level gauges, or differential pressure level gauges also exhibit severe up-and-down movement. Solution: Repair any faults in the steam-water separation device inside the drum; eliminate the effects of regular blowdown, continuous blowdown, feedwater, and combustion on the drum water level. (Extremely low probability) 2. Signal-to-noise interference: Such interference is difficult to detect and measure, unless it occurs over a prolonged period; an oscilloscope can be used to capture it. Solution: ① Ensure that the cable shielding layer on the secondary meter side is properly grounded, with a grounding resistance of less than 4 ohms (the ground connection should not be made to the meter cabinet itself, as the cabinet is not a reliable grounding conductor; in some cases, the cabinet also needs to be insulated, and special grounding wires must be used to connect it to the grounding busbar). (General probability) ② Ensure that the cable shielding wire on the electrode cylinder side is not grounded; if it is exposed, insulation treatment should be applied to ensure single-ended grounding of the signal shielding. (High probability) 3. Interference caused by the accumulation of capacitance on the signal lines. This is manifested as sudden fluctuations in the readings of the instrument after it has been operating for some time; thereafter, it functions normally for another period. The impact is minimal and the duration is short, yet no cause can be identified. Solution: ① Replace the cable and its routing path ； ②Replace the secondary meter. (Low probability) ③ Turning off the power and then turning it back on can extend the time before this fault occurs, but it does not resolve the issue permanently. 4. The wiring of the common signal ground (refer to the instruction manual for the electric contact level gauge) is unreliable, especially on the side of the tank at the installation site. Solution: Check and tighten the common signal wires. (High probability)