8440-1713/D WOODWARD Digital Synchronous System Controller

Description

PLC functional faults and their handling
The malfunction caused by PLC interference will affect the system signal, resulting in a decrease in system control accuracy, loss of internal data in the PLC, machine malfunction, and in severe cases, personal and equipment accidents may occur. Take corresponding technical measures. It is necessary to enhance the anti-interference ability of PLC systems. Interference includes internal interference and external interference. External interference in the on-site environment is random and independent of the system structure. Interference sources can only be limited based on specific circumstances.

Internal interference is related to the system structure. By carefully designing system circuits or filtering, etc. It can achieve maximum suppression of interference. The anti-interference technical measures for PLC production sites are usually considered from multiple aspects such as grounding protection, grounding method, shielding, and noise resistance. For strong current equipment in the power supply system. The metal components such as its shell, cabinet body, rack, base, and control handle must be protected and grounded: the internal circuit of the PLC includes EPU, memory, and other interfaces that are jointly connected to digital ground, while the external circuit includes A/D, D/A, and other common analog ground.

The PLC floor is connected to the central grounding point with thick and short copper wires to prevent noise interference. When the PLC is not grounded, the installation bracket of the PLC should be capacitive grounded to suppress electromagnetic interference. In the PLC system. The wires mainly include PLC and load power lines, AC voltage digital signal lines, DC digital signal lines, analog signal lines, etc. Depending on the function of the wiring.

The anti-interference measures are as follows:

1. Only shielded analog input signal lines can be installed in the same cable tray as digital signal lines in the electrical cabinet wiring arrangement: DC voltage lines and analog signal lines cannot be installed in the same cable tray as AC flow voltage lines: only 220V power lines can be installed in the same cable tray as signal lines; The inlet and outlet shielding of the electrical cabinet must be grounded.

2. The external wiring of the electrical cabinet should be arranged with independent cables for the digital signal lines and analog signal lines of DC and AC voltages (shielded cables are required). The signal cable and power cable should be installed in the same cable tray, but in order to improve noise resistance, it is recommended to interval them by about 10cm.

3. Shielding of PLC casing: Generally, the casing and electrical cabinet are suspended, and an equipotential shielding board is installed on the PLC casing floor to maintain a certain connection between the protective grounding and the floor. When using copper wires, their cross-sectional area is not less than 10mm 2 to form an equipotential shielding body and effectively eliminate electromagnetic interference. Cable shielding, generally suitable for carrying small signals (mV or μ V) The analog signal line should connect one end of the cable shielding body in the electrical cabinet to the shielding mother body, and the shielding of the digital signal line should not exceed the shielding mother body; The shielded bus for analog quantities can be insulated. And connect the central point to the reference potential or ground; Grounding both ends of the digital signal line can eliminate high-frequency interference.

4. Anti noise measures shall be taken to shield the parts of transformers exposed to strong magnetic fields with metal, and fluorescent lamps shall not be used for lighting inside the electrical control cabinet. In addition, the PLC system control power supply should also adopt corresponding anti-interference measures. Because the power supply of the PLC control system. Generally, it is 220V mains power.

The transient process of the power grid often occurs, and the switching of inductive loads or thyristor devices with large power fluctuations can easily cause voltage gaps or burrs. If power is directly supplied through PLC and I/O templates, it will cause adverse consequences. The anti-interference methods for PLC system power supply include:

(1) using isolation transformers;

(2) Adopting low-pass filters;

(3) Apply spectrum equalization method.

Among them, isolation transformers are commonly used because PLC and I/O module power supplies commonly use DC24V, which need to be reduced by isolation transformers and then rectified by rectifier bridges for supply.

8440-1022 SPM-D2111B/PSV Replace with MFR2 or EG2500
8440-1023 SPM-D2115B/PSV Replace with MFR2 or EG2500
8440-1024 SPM-D2141B/PSV Replace with MFR2 or EG2500
8440-1025 SPM-D2145B/PSV Replace with MFR2 or EG2500
8440-1026 SPM-D2111B/PSVX Replace with MFR2 or EG2500
8440-1027 SPM-D2115B/PSVX Replace with MFR2 or EG2500
8440-1029 SPM-D2145B/PSVX Replace with MFR2 or EG2500
8440-1458 SPM-D1040B/HJV Replace with MFR2PSV
8440-1600 SPM-D1010B/HJV Replace with MFR2PSV
8440-1686 SPM-D1145B/LSR Replace with 8440-1666, limitation only 1 x raise&lower
8440-1703 SPM-D1115B/LSR Replace with 8440-1706, limitation only 1 x raise&lower
8440-1708 SPM-D1111B/LSR Replace with 8440-1705, limitation only 1 x raise&lower,limitation
DI voltage max 40V
8440-1709 SPM-D1115B/LSR Replace with 8440-1706, limitation only 1 x raise&lower,limitation
DI voltage max 40V
8440-1711 SPM-D1145B/LSR Replace with 8440-1666, limitation only 1 x raise&lower,limitation
DI voltage max 40V
8440-1713 SPM-D1115B/LSXR Replace with 8440-1706 imitation DI voltage max 40V
8440-1715 SPM-D1145B/LSXR Replace with 8440-1666 limitation DI voltage max 40V
8440-1872 SPM-D10B/PSY5-FU-A Replace with similar SPM-D1040B/X 8440-1301
8440-1874 SPM-D10B/PSY5-FU-A-W Replace with similar SPM-D1040B/XN 8440-1668