Delta PLC manufacturer: How to deal with Mitsubishi PLC fault?
Mitsubishi PLC's disturbance will affect the system signal, resulting in reduced control accuracy, Mitsubishi PLC internal data loss, machine malfunction In severe cases, an accident may occur. Delta PLC manufacturers today discussed with us Mitsubishi PLC software problems.
There are external disturbances and internal disturbances. External disturbances in the on-site environment are random, independent of the architecture, and can only be limited to the specific sources of disturbance sources; internal disturbances are related to the architecture, and through careful design of software filtering, etc., the disturbance can be greatly limited. Always. Mitsubishi PLC production site anti-interference technology methods, generally from the grounding protection, wiring organization, shielding and anti-noise and other aspects.
1) Grounding outside the electrical cabinet
Digital signal line and analog signal line for DC and communication voltage (to be shielded cable) must use separate cables; signal lines Cables can be installed in the cable duct with the power cable, but for improved noise immunity, it is recommended to distance them by 10cm.
2) Wiring in the electrical cabinet
The analog input signal can be shielded from the same cable trough as the digital signal cable; DC voltage digital signal line and analog signal line Can not be in the same cable slot as the communication voltage line; as long as the shielded 220v power cable can be installed in the same cable as the signal cable; the shield of the electrical cabinet inlet and outlet must be grounded.
Mitsubishi PLC chassis shielding, generally speaking, the chassis and electrical cabinets are floating, and an equivalent shielding plate is installed on the floor of Mitsubishi PLC chassis to protect the low Keep a little connection on the bottom plate, use copper wire, the cross-sectional area is not less than 10mm2, with the mechanism equipotential shield, effectively eliminate the electromagnetic field disturbance.
Cable shielding, generally for analog signal lines that intercept small signals (mV or uV), the cable shielding in the electrical cabinet should not exceed the shielding matrix; the shielding bus for analog signals can be insulated. Connect the central point to the reference point or ground; the grounding of the cable at both ends of the digital signal line ensures better sweeping of high frequency disturbances.
4) Noise method
Metal shielding is applied to the part of the strong magnetic field (such as the transformer), and the interior of the electric control cabinet is illuminated by fluorescent lamps. In addition, Mitsubishi PLC control system power supply should also use the corresponding anti-interference method. Since the power supply of Mitsubishi PLC control system is generally 220v mains, the transient process of the mains grid is often happening. The rational load of the power supply fluctuation or the switching of the thyristor device can easily form a gap or brush for the electric industry, such as direct power supply. Give PLC and I/O templates, which will cause adverse consequences. Mitsubishi PLC control system power supply anti-interference method is the choice of isolation transformer, low-pass filter and application of spectrum equalization method.