The PLC analog input module is used to collect analog values such as voltage and current, thermal resistance thermocouples, or temperature, and then transmit them to the intelligent module on the computer through the bus. In fact, it is a device that collects analog signals from remote sites to a computer. Analog signals represent arbitrary values that continuously change within a certain range, representing a state opposite to digital signals. Generally, analog signals are used to collect and display parameters such as voltage, current, or frequency of things.

DCS, also known as a distributed control system or in some materials, is a new type of computer control system compared to centralized control systems. It is developed and evolved from centralized control systems. In terms of system functions, the difference between DCS and centralized control systems is not significant, but the implementation methods of system functions are completely different.

Analog control technology has been widely applied in practical production and has become an important component in the automation industry and machine equipment. Analog signals are an important source in signal acquisition, which is different from our ordinary IO control. For example, some are switch input modules, and these signals are either 0 or 1. If it is for analog signals, it is not simply 0 or 1, it is a continuously changing numerical value. Just like temperature signals, flow signals, displacement signals, and so on, these are not simply on or off, but they are all continuously changing quantities.

At this point, if only 0 or 1 is used to express the temperature signal collected externally, for example, if the temperature range is between minus ten degrees or above thirty degrees, the temperature signal cannot be represented by the state of 0 or 1. Therefore, such digital signals need to be expressed through corresponding analog signals, Moreover, this form of signal acquisition is not easily obtainable through any means. That is to say, it is necessary to collect analog signals through some corresponding analog modules. To collect analog signals, an analog input module is used. To control external devices and other devices for action, an analog output module is used to control the frequency of the frequency converter.

In various industries such as automation and information systems, there are applications of PLC analog input modules. In practice, the application of analog input modules can be easily seen. The analog input module collects analog signals. If it is collecting external pressure sensors, the analog signals collected by the pressure sensors are collected internally through the module and then processed accordingly. The analog output module outputs some signals through this module and then goes to external devices of Confucius, such as frequency converters. The frequency converter needs to collect signals of 0-10V, corresponding to the frequency of 0-50HZ of the frequency converter, so it needs to be controlled by this module accordingly. This is the application method of analog input and output.