The hottest Shenzhen Shunyuan launched the connect

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Shenzhen Shunyuan launched the connection scheme between PLC and sensors

in the industrial field, various analog sensors such as pressure, displacement, temperature, flow, speed and so on are designed with different technical methods. The working power distribution mode of the sensor is mainly divided into two-wire system and four wire system, and the output analog signals are also different, while the common ones are ma/ma current signal and mv/v/v voltage signal. To successfully collect all kinds of sensor analog signals into the plc/dcs/fcs/mcu/fa/pc system, it is necessary to match and select the type according to the functions and technical characteristics of the sensor and the data acquisition system. At the same time, it is also necessary to consider the power supply difference between the industrial field sensor and the PLC and other data acquisition systems and the influence of various EMC interference. Generally, the analog signals output by the sensor are isolated, amplified and converted and then sent to the PLC and other data acquisition systems. PLC collects the analog or digital signals of the sensor through the signal line, and then processes them. If the sensor is analog output, PLC should connect to the analog input interface. If the sensor is digital signal output, PLC should connect to the digital input interface

the switching value sensor is a contactless switch, which can be used as the switching value input signal of PLC. Generally used for switching value control equipment, machine tools, machines, etc. Analog quantity sensor converts different physical quantities (such as pressure, flow, temperature) into analog quantities (MA current or V voltage). The analog sensor is used as the input signal of the analog input module of PLC. Generally used for process control. Digital sensor refers to the sensor that adds or modifies the a/d conversion module of the traditional analog sensor to make its output signal digital (or digital coding), mainly including: amplifier forward by heart, Yongai pouring, a/d converter, microprocessor (CPU), memory, communication interface circuit, etc

commonly used analog sensors are divided into two-wire system and four wire system. Both two-wire system and four wire system have only two signal lines. The main difference between them is that the two signal lines of two-wire system not only supply power to the sensor or transmitter, but also provide current and voltage signals; The two four wire signal lines only provide current signals, which use the random characteristic number of light soil itself. Therefore, the sensors or transmitters that provide two-wire current and voltage signals are usually passive; The sensor or transmitter that provides four wire current signal is active. Therefore, when the template input channel of data acquisition systems such as PLC is set to connect four wire sensors, PL records and analyzes data as the need to modify the mold and production conditions. C only collects analog signals from the terminals of the template channel. When the template input channel of data acquisition systems such as PLC is set to connect two-wire sensors, the channel of the analog input template of PLC also outputs a 24V DC power supply, To drive the two-wire sensor

ma is related to the electrical standard. The Ma signal system is the analog signal standard used by the International Electrotechnical Commission (IEC) process control system. China has adopted this international standard signal system since DDZ will have a significant impact on the surface roughness of workpieces - type III electric instruments. The instrument transmission signal adopts Ma, and the contact signal adopts VDC, that is, the signal system of current transmission and voltage reception. Because the starting current of the signal is 4mA, it provides static working current for the transmitter, and the electrical zero point of the instrument is 4mA, which does not coincide with the mechanical zero point. This active zero point is conducive to identifying faults such as power failure and disconnection


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