(1) Inspection methods There are many repair methods for electronic truck scales, such as observation method, substitution method, tapping method, wire drawing method, instrument inspection method, code diagnosis method, etc. In actual repair work, it is often necessary to comprehensively apply Ways. Don't die hard, the key is to pay attention to analysis and accumulate experience, in order to avoid detours and quickly find faults .
(2) Troubleshooting example 1. Fault phenomenon: A 50-ton electronic truck scale of a company sometimes displays a negative overload after being turned on, and sometimes returns to normal after restarting. This phenomenon often occurs.
Fault analysis: Sometimes there is no fault, it is not the reason of the meter. Check that the weighing platform, connectors, and limits are normal, and the mechanical reasons are excluded. Recheck all the solder joints on the terminal board to eliminate the possibility of soldering or soldering. After zui, using "alternative method" and "wire drawing method" to find out that the fault is caused by a certain sensor. After checking, it is confirmed that the signal line of one sensor is bitten by the mouse, and sometimes it can be touched, the meter is normal, sometimes it is in the off state, and the meter displays negative overload.
Trouble-shooting: Cut the sensor signal line from the bite, and after treating with epoxy resin, make a joint and the truck scale will return to normal.
2. Fault phenomenon: The 60-ton truck scale meter of our factory shows unstable, jumping from +20 to -100.
Fault analysis: Firstly, the simulator is used to check that the instrument is normal. If it is not a mechanical fault, the fault may be in the junction box or sensor. The truck scale has three weighing platforms, three junction boxes, and eight sensors. After inspection, it is found that the instrument is displayed normally after the north surface platform is connected to the signal bus of the intermediate junction box, and the south platform is connected to the middle wiring. When the signal line of the box is welded, the meter display is still unstable, and it is concluded that the south scale platform is normal, and the fault is caused by the north scale platform, including four sensors and two junction boxes. Using a multimeter to measure, it was found that the excitation voltage of the signal line connected to the north surface of the intermediate junction box was 11 volts and unstable, while the normal value was 12.5 volts, and the +EX wiring hole on the inspection wiring board was soldered.
Trouble-shooting: Weld a short-circuit line and directly connect the +EX terminal to the +EX end of the instrument. The fault is solved.
3. Fault phenomenon: A company's 50-ton truck scale boot meter only displays a negative sign.
Fault analysis: Check the instrument with “Alternative Method”, unplug the signal bus of the instrument, connect the simulator, and then adjust the simulator. The instrument has no response, indicating that the instrument is bad.
Troubleshooting: Repair damaged instruments.
4. Fault phenomenon: A 50-ton truck scale meter of a company shows negative overload.
Fault analysis: Firstly, use the "alternative method" to check that the instrument is good, check the junction box, measure the output signal of the sensor with a multimeter, find that the signal is not normal, and the wiring board itself is normal, drag the signal cable of the sensor out and check it. The signal cable with four sensors was bitten by the mouse to varying degrees. After lifting the weighing platform, it was found that the longitudinal limit and the three connectors were broken.
Trouble-shooting: Cut the sensor signal lines on the two corners from the bite, because the line placed in the original position is not long enough, so move to the middle, and move the two good ones in the middle to the corner, and change again. Two new sensors, soldered to the limit, replaced with good connectors, recalibrated and debugged, and solved the problem.
5. Fault phenomenon: The drift of the 50-ton truck scale of our factory has occurred. When weigh more than ten tons of heavy trucks, it is one ton less than another scale.
Fault analysis: Through inspection, the possibility of mechanical exclusion is first ruled out, which is estimated to be caused by deterioration of sensor performance. Using a 5 ton weight compression angle, it was found that the two sensors in the middle were large in error, one was 160 kilograms less than the standard weight, and the other was 540 kilograms less, while the two sensors at the top four were basically normal, and it was estimated that the sensor on the large angle of the error was damaged.
Troubleshooting: Replace the damaged sensor and solve the problem.
6. Fault phenomenon: a unit of 50 tons of truck scale zero point instability, jump 80 kg, and only jump 80 kg.
Fault analysis: It is estimated that the mechanical part is faulty. After checking, the limit is normal. There is only one connecting piece loose in the middle. It can be rotated by hand. After lifting the weighing platform, the level is measured by the water level meter and the plane position of the six corners is found. The difference is 11mm.
Trouble-shooting: Re-leveling with stainless steel plate, after the wiring is installed, the fault is solved.
7. Fault phenomenon: Our factory's 50-ton truck scale (using digital sensor) shows “E801～06 hopping” every day at around 10:00 am, and returns to normal at night, but the same fault occurs at about 10:00 the next morning. phenomenon.
Fault analysis: After checking the instrument, junction box and signal bus are normal, it is estimated that the fault is caused by a sensor. Zui finally finds that the No. 1 sensor cable is sandwiched between the positioning base plate and the foundation. There are two wires due to the squeeze. Broken skin, and the scattered cement solidifies. When the temperature is high, the two broken skin lines cause a fault. When the temperature is low, the shrinkage does not touch, and the meter returns to normal.
Trouble shooting: Cut the sensor signal line from the broken skin, re-do the joint, and solve the problem.

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