When using a level gauge, in addition to understanding its normal operation and routine maintenance, it is essential to master certain basic troubleshooting methods. The most commonly used methods in maintenance are direct sensing method, panel compression method, testing and identification method, tracing and tracking method, comparative substitution method, and dumb level separation method. The following provides explanations for these six methods.
Direct Sensing Method
The direct sensing method involves using the direct senses of sight, hearing, smell, and touch to make judgments. It is an indispensable auxiliary means in maintenance and can be applied throughout the entire maintenance process of sections, levels, routes, and points. It is particularly important when pinpointing faults.
Panel Compression Method
The panel compression method utilizes the control switches, knobs, sockets, buttons, and indicator devices on the panel of a float level gauge to compress faults in the internal circuit. It is a commonly used external compression fault method in determining fault phenomena and judging fault sections and levels. However, as the panel of the level gauge may not always be comprehensive or the best place to control faults, it sometimes needs to be combined with other methods. Therefore, the panel compression method is generally an effective auxiliary method.
Testing and Identification Method
The testing and identification method involves using instrument measurements of circuit data for quantitative identification. It is the most commonly used basic method for compressing faults in routes and points. This method can be further categorized into powered testing and non-powered testing. Powered testing includes voltage and current testing related to the liquid level gauge, testing of circuit component parameters, and testing of the main technical indicators of the liquid level gauge. The most commonly used are voltage and current testing. Non-powered testing refers to the testing of relevant circuits, devices, components, and insulation resistance of the liquid level gauge. By comparing test data with normal data, faults and their ranges can be identified.
Tracing and Tracking Method
The tracing and tracking method is a basic method for troubleshooting low sensitivity faults in magnetic flap liquid level gauges. It includes interference tracking, signal tracking, and signal tracing.
Tap each electronic device level by level from the final of the level gauge using a small awl in hand. Judge faults in sections and levels based on the size of the actuator’s action and the presence of speaker sound. For example, if during interference tracking, a certain level is found to be normal, and when tapping the previous level, there is no sound or very little sound, then the interval between the rear level and the front level is the fault location. Interference tracking is a commonly used method in the maintenance of magnetic float liquid level gauges.
Use a signal tracer (the simplest is a detector composed of a semiconductor diode and a headphone) to check faults in the compressed magnetic flipping column liquid level gauge. The method involves outputting a certain signal from a signal generator to the liquid level gauge to be repaired, and using the signal tracer to monitor the signal from the front stage to determine the fault level.
Use a signal generator to input audio, intermediate frequency, and high-frequency signals into each level of the liquid level gauge step by step. At the same time, check the output size obtained from the terminal device and whether there are any abnormal phenomena to inspect whether each level is working normally and determine the fault level.
Comparative Substitution Method
The comparative substitution method involves comparing and exchanging two similar types of liquid level gauges, components, devices, etc., to identify compression faults related to their condition (good or bad, normal or abnormal). In the absence of instruments or in cases where the liquid level gauge is not well understood, the comparative substitution method is a relatively simple and basic method to determine whether a certain fault point exists. For example, if a magnetic flowmeter is damaged during operation, it can be compared with a normal electromagnetic flowmeter to identify the fault. Similarly, if a part (float) of the liquid level gauge is damaged, it can be compared with the float of a normal liquid level gauge to identify the fault. Therefore, it is a basic method to determine certain fault points.
Dumb Level Separation Method
The dumb level separation method is mainly used to troubleshoot faults such as calling sound, buzzing (AC sound), and noise in level gauges. The specific method is to use a large-capacity capacitor or short-circuit rod to short-circuit the signal input circuit and signal output circuit of each level of the liquid level gauge step by step, from front to back, to determine the fault section and level. For example, when short-circuiting a certain level, if the fault phenomenon remains unchanged or has little impact, and when short-circuiting the next level, the fault disappears, then the interval between the rear level and the front level and the relevant circuit is the location of the fault.