Ultra-pure water equipment automatic control system alarm, indicating that the ultra-pure water equipment failure.
1, the system control loop and the main loop in a small space in the same control cabinet, there may be control power and the main loop power supply interfere with each other.
2, the system PLC, touch screen, thermal relay alarm points, on-site float level high and low level control points and other electrical equipment *** with a 24V power supply, series and parallel connection circuit is too much, if one of the point of failure may lead to damage to any one of the circuit or more electrical equipment.
3, the main circuit of the AC contactor coil directly connected to the output point of the PLC, without any isolation measures in the middle, which can easily lead to PLC output point of the current is too large and damage to the PLC.
4, the environment of the ultra-pure water room is relatively humid, the leakage of the bare electrical equipment outside the increase in the number of control cabinets, control circuits within the original control cabinets will be relocated to the new control cabinets so that it is separated from the main circuit control systems, eliminating the need to control the main circuit of the system. Separate from the main circuit, exempt from the control loop and the main circuit may exist in the power supply interference, and to solve the problem of 24V power supply series parallel circuit is too much.
5, EDI module power supply from the control cabinet at the bottom of a large isolation transformer supply. Its placement in the control cabinet at the bottom of the control cabinet and the control cabinet sealing is not good, easy to stain the dust resulting in poor contact with the terminals, affecting the EDI module power supply.
How to solve?
1, the PLC from the original control cabinet to the newly added control cabinet. In the original control cabinet to install the PLC location to install the terminal block, the line in accordance with the line number sequentially connected to the terminal block.
2, add a new isolation transformer alone to the PLC power supply, to ensure the normal operation of the control system core PLC.
3, increase a 24V power supply, the original 24V circuit is split into two, one dedicated to the touch screen power supply, the other for the PLC DI input points and AI module power supply. It contains thermal relay alarm point and on-site float type high and low level switch input point power supply.