Are generally very strong anti-jamming capability of the PLC itself. Typically, only the PLC power supply and power equipment of power separate wiring for the power cord to the interference, in general, strong enough to inhibit the ability. However, if special circumstances, the power supply noise is particularly serious, can be added by one shielded isolation transformer to reduce the interference between the equipment and to improve system reliability. If a system expansion unit, its power must be shared with the basic unit of a switching control that is, they power up and down must be carried out. A good grounding is an important condition to ensure the PLC safe and reliable operation.

The purpose of the grounding usually have two, one for safety, and the other in order to suppress interference. Improve the grounding system is one of the PLC control system anti-jamming measures. Ground to play a significant role in the elimination of interference. The ground here is to determine the system potential, rather than signaling system return ground. PLC control system suspended metal frame, they are afraid of air interfere with the air line, need to have decided the potential of the ground. AC to PLC control system power supply necessary, constitute one of the powered two-loop it through the transformer center point. The loop current, a variety of harmonic currents, etc. is a serious source of interference. AC ground, DC ground, analog ground and digital ground should be kept separate. Digital and analog ground point to the best home suspension. The potential difference between the ground each as small as possible, try to bold the ground conditions can be circular ground. The system ground terminals (LG) is the neutral terminal of the anti-jamming, usually do not require grounding However, when electromagnetic interference is more serious, this terminal with the access terminals of the earth connection.