The selection of the Siemens S7-300 PLC is based on the functional and capacity requirements of the production process, while also considering ease of maintenance, availability of spare parts, scalability, and the need for special functions. This guide provides a detailed overview of key considerations when using the S7-300 series PLC in the Aichi Mall Xiaobian project.
**(1) Anti-interference Measures**
Power line noise can lead to voltage distortion, causing overvoltage, overload, overheating, or even component failure in the system, which may result in malfunctions of the PLC and other control devices. To prevent this, it's recommended to install anti-interference solutions such as shielded transformers or power supply filters at the power inlet. The grounding of the power filter should be connected directly to the central protective ground with the shortest possible wire. For DC power supplies, adding a differential capacitor can help suppress interference effectively.
**(2) Protective Grounding**
The switchboard’s protective ground should be connected using a copper wire of at least 10 mm² in cross-section. Control cabinets located next to each other should maintain good electrical contact and be reliably grounded. Lightning protection is also essential. Shielded cables are typically used for bus lines, with the shielding layer grounded at both ends. For analog signal cables, double-shielded cables are recommended, with the outer shield grounded at both ends. To prevent lightning-induced surges from entering the system, surge absorbers can be installed.
**(3) Signal Shielding**
Proper signal shielding is crucial for reliable operation. Shielded cables are generally used for transmitting analog signals. When multiple analog cables are shared within a multi-core shielded cable or when two separate shielded cables are used, proper shielding must be ensured. One end of the cable shield (typically at the control cabinet side) should be securely grounded to minimize noise and interference.
**(4) Soft Button Method for Configuration**
When hard point settings are unavailable or not feasible on-site, the soft button method on the operator interface can be used to manage selection or control mode changes. Additionally, direct wiring to devices like inverters or smart meters is recommended to ensure more stable and accurate communication.
**(5) Optimal PLC Environment**
The installation environment of the PLC should be carefully planned to enhance system immunity to interference. The PLC should be placed away from high-voltage cabinets, high-frequency equipment, power panels, and high-current units. Communication and analog signal cables should not share trenches with other devices or screens. Fluorescent lighting should be avoided inside the PLC cabinet. Although the S7-300 is designed for industrial use, it should still be protected from direct vibrations, shocks, sunlight, oil mist, and water exposure. Avoid placing it near corrosive gases, excessive dust, or heat sources. Also, ensure that no conductive impurities enter the controller.
40L Agriculture Drone Agricultural Sprayer Agricultural Spraying Drone Drones Agriculture Sprayer 30L Agriculture Drone Fertilizer Drone
Xuzhou Jitian Intelligent Equipment Co. Ltd , https://www.jitianintelligent.com