1. The PC (Power Probe) must not be located in the same switchgear as high-voltage electrical equipment. Electrical components such as relays and contactors whose coils are located in the same switchgear as the PC should be connected in parallel with an RC arc suppression circuit. The PC should be kept away from strong interference sources, such as high-power thyristor devices, high-frequency welding machines, and large power equipment.
2. For general applications, the switching signals supplied by external electrical components such as buttons, limit switches, and proximity switches do not have strict requirements on the cables, so ordinary cables can be used. If the signal transmission distance is long, shielded cables can be used; shielded cables are also used for analog signals and high-speed signals.
3. Signal and power cables should be routed separately. Power cables should be run separately; different types of cables should be installed in different conduits, and signal cables should be installed in dedicated cable conduits, as close as possible to the ground wire or a grounded metal conductor. When the signal line length exceeds 300m, an intermediate relay should be used to transfer the signal, or a PC's remote I/O module should be used. Power lines and I/O lines should also be routed separately with a certain distance maintained. If they must be routed in the same conduit, shielded cables should be used. AC circuit cables and DC circuit cables should use different cables.
4. For signal transmission, when analog input/output signals are far from the PC, a current transmission method of 4-20mA or 0-10mA should be selected instead of a voltage transmission method. The shielding layer of the shielding cable transmitting analog signals should be grounded at one end. To discharge high-frequency interference, the shielding layer of digital signal lines should be connected in parallel with a potential equalization line, and both ends of the shielding layer should be grounded.
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