1. **Stratified Troubleshooting:** First Identify the Major Category, Then Delve Deeper
This is the core diagnostic technique, following the order of "Finished Product → Operation → Electrical":
If the equipment operates, but the finished product has problems (inconsistent tension/paper breakage/dimensional deviation): Directly identify the tension control/meter encoder as faulty; don't waste time checking the power supply.
If the equipment won't start at all/indicator lights are off: Prioritize checking the power supply and safety circuits; after eliminating simpler issues, check the PLC.
If the fault is irregular, resolves with a restart, and then recurs: Directly investigate interference issues; don't blindly replace components.
2. **Replacement Verification Method:** Quickly Identify Damaged Components
For components that are difficult to measure, such as circuit boards and sensors, using the replacement method can save half the time:
For example, if you suspect a damaged 7805 voltage regulator in the photoelectric protection circuit, directly replace it with a new one of the same model for testing. If it works after replacement, the fault is confirmed; there's no need to repeatedly measure the voltage.
If you suspect an abnormal tension sensor, replace it with a working sensor of the same model. If the fault disappears, the sensor is the problem, ruling out parameter and wiring issues.
3. Parameter Comparison Method: Quickly Eliminate Human-Induced Faults
For parameter-related faults such as communication and tension, compare the current settings with the standard parameter table:
For communication faults, prioritize checking the station number and baud rate. If they are inconsistent with system requirements, correct them directly. 80% of human-induced communication faults can be resolved directly. For unstable tension, compare the current tension parameters with those used in normal production. If the deviation exceeds a reasonable range, restore the factory settings and then fine-tune.
4. Disconnection and Isolation Method: Differentiate Between Mechanical and Electrical Faults
For faults such as motor not turning or overcurrent reports, disconnecting the load can quickly identify the cause:
Disconnect the connection between the motor and the DC unit. If the fault persists after restarting the unit, it is definitely an electrical (DC unit) fault. If no fault is reported, it is either mechanical jamming or a motor fault, eliminating the need for repeated troubleshooting in the electrical section.
5. Typical Fault Quick Reference Techniques: Match Faults to Faults to Save Time
Remember the typical characteristics of common faults for easy identification:
If the bridge rectifier burns out quickly after replacement → directly replace the 7805 voltage regulator; 90% of the time, it's the rectifier causing a short circuit.
If the fault recurs randomly and improves after a restart → directly check the grounding and wiring; it's definitely electromagnetic interference.
For communication faults, check parameters first, then the terminating resistor, and finally the wiring; checking from high probability to low probability is the correct approach.
For armature overvoltage, adjust parameters first (extend acceleration/deceleration), then check the encoder; no need to disassemble the device directly.
6. Safety Diagnostic Tips
Before power-off maintenance, take photos to record the wiring positions to avoid incorrect rewiring and secondary faults. When measuring voltage, measure the power input line first, then the branches; measuring from the common terminal to the specific terminals is more efficient.
