What measures can improve the PLC to interfere with the performance of the system

1, with excellent performance of power, restrain interference in PLC controller control system, the introduction of grid power occupies very important position. The string into the PLC control system of power network disturbance mainly through PLC system power supply ( Such as CPU power supply, I/O power supply, etc. ) , transmitter power supply, and with PLC system has a direct electrical connection in the instrument coupled into the power supply, etc. Now, for the power of the power supply, PLC system generally adopts the isolation performance is better power supply, and for the power of the transmitter power and PLC system has a direct electrical connection of the power supply, and not enough attention, although a certain isolation measures, but it's not common, mainly using isolation transformer distribution parameters is large, suppress interference ability is poor, the power coupling and string into the common-mode interference and the differential-mode interference. So for transmitter and common signal meter power supply should choose small distributed capacitance, inhibition zone ( If use multiple isolation and the leakage inductance of the shielding and technology) The distributor, in order to reduce interference of PLC system. In addition, ensure the feed point don't interrupt, can be used on-line uninterrupted power supply ( UPS) Power supply, increase the safety and reliability of power supply. And UPS also has strong interference isolation performance, is a kind of ideal power supply of PLC controller control system. 2, cable selection of ao and set in order to reduce the power cable radiation electromagnetic interference, especially the feeder cable frequency conversion device. In a project, the writer used the copper tape armoured shield of power cable, which reduces the power line to produce electromagnetic interference, satisfactory results have been achieved after the project put into production. Different types of signals respectively by different cable transmission, signal cable should be set according to the transmission signal type layered ao, it is forbidden to use the same cable of different wire transmit power source and the signal at the same time, avoid signal lines parallel to the power cable near the ao set, in order to reduce electromagnetic interference. 3, hardware filter and software if measures because of the complexity of the electromagnetic interference resistance, it is impossible to simply eliminating the interference influence, therefore in the PLC control system software design and configuration, but should also in the aspect of software anti-interference processing, further improve the reliability of the system. Commonly used some of the measures: digital filter and plastic power frequency sampling, which can effectively eliminate periodic interference; Regular calibration reference point potential, and USES the dynamic zero, which can effectively prevent potential drift; USES the information redundancy technology, designs the corresponding software logo; Adopt indirect jump, software trap, software structure reliability. Signal before access to the computer, and capacitance between the signal and ground, in order to reduce common-mode interference; In the signal between the poles with filter can reduce differential mode interference. Often the large fluctuation due to the instantaneous interference, if only in instantaneous sampling control calculation produces large error, digital filtering methods can be used for this purpose. The analog signal after A/D conversion into discrete digital signal, and then will form of data according to the time sequence in the PLC memory. Using digital filtering program for processing, filter to obtain pure signal noise part, can be used for the input signal m times average value of a sample to replace the current value, but not well usually of each sample. Time for an average, but once per sample with recent m - l time sampling values in history, reaction speed, this method has good real-time performance, after the input signal is processed with dry signals or loop adjustment, effectively suppress the noise. By dry harsh industrial environments, the jamming signal is more, the I/O signal transmission distance is longer, often make a wrong signal. In order to improve the reliability of the system is running, make the PLC in the signal error qian condition timely find errors, and can eliminate the influence of the error to continue to work, can be used in the programming software fault-tolerant technology. 4, correct selection of location, perfect the purpose of the grounding system usually has two, one is for the sake of safety, the second is to suppress interference. Perfect grounding system is PLC control system is one of the important measures of resistance to electromagnetic interference. System grounding method are: float way, direct grounding way and capacitor three ways. For PLC control system, it belongs to the low level control device, direct grounding method should be adopted. Due to the signal cable capacitance and the influence of input device such as filtering, between the signal switching frequency is generally less than 1 MHZ, so the grounding line adopts PLC control system earthing and series point grounding method. Centralized layout of PLC controller system is suitable for parallel point grounding method, cabinet put oneself in another's position of each device center ground to separate grounding line to extremely. If the device spacing is bigger, series one-point earthing methods should be adopted. With a large cross-section of copper bus bar ( Or cable) Cabinet put oneself in another's position of connecting the device center location, and then connect the ground bus directly grounding. Ground wire using section 22 was greater than copper wires, copper platoon of total bus using cross section is greater than 60 was. Grounding pole grounding resistance is less than 2 Ω, very best buried in 10 ~ 15 m far away from buildings, Or between the controller and not more than 50 m) And the PLC system of by site must with high voltage equipment location are separated by more than 10 m. Signal grounding, shield should be against the side of the signal grounding; Not grounding, grounding in PLC, Signal lines in the middle joint, shielding layer should be firmly connected and insulating treatment, multipoint earthing must be avoided; Multiple signal measuring point is shielded twisted-pair cable and multi-fiber twisted-pair cable connection, the total screen each shield should be connected well, and the insulation treatment. Select the appropriate is located at a single point of contact.
Shenzhen Coolmay Technology Co., Ltd. devises a regular, independent, transparent and objective assessment mechanism to evaluate country performance.
For good quality programmable control systems and a good variety of products to choose from, visit Shenzhen Coolmay Technology Co., Ltd. at Coolmay PLC.
Although the core manufacturing factor of plc manufacturers is high technology, smart customers know that we need to enhance our material quality and producing standard.
Shenzhen Coolmay Technology Co., Ltd. expects to reach the desired profits in the first year and does not anticipate serious cash flow problems.
It's the consistent experience that builds trust and loyalty. Creating a personality and platform that is scalable will allow you to evolve plc manufacturers with your consumers.