The PLC analog input module is used to collect analog values, such as voltage, current, thermal resistance, thermocouple, temperature, etc., 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, and represent a state that is 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 distributed control system or distributed control system in some sources, is a new type of computer control system that has developed and evolved from centralized control systems. In terms of system functionality, there is not much difference between DCS and centralized control systems, but the implementation methods of system functionality are completely different.
Analog control technology has been widely applied in practical production and has become an important component in the automation industry and machinery equipment. Analog signals are an important source in normal 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 continuous variables.
At this point, it is simply impossible to express the temperature signal collected externally through 0 or 1. For example, if the temperature range is -10 degrees Celsius or -30 degrees Celsius, 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, and this form of signal acquisition cannot be easily obtained through any means.
That is to say, it is necessary to collect analog signals through corresponding analog modules. To collect analog signals, an analog input module is used. To control external devices and control other devices to operate, if it is to control the frequency of the frequency converter, an analog output module is required.
In various industries, automation and information systems have the application of PLC analog input modules. In practice, the application of analog modules can be intuitively seen. Analog input modules collect 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 sends them to external devices, such as a frequency converter. The frequency converter needs to collect 0-10V signals, corresponding to the 0-50HZ frequency of the frequency converter. Therefore, it is necessary to use such a module to control it accordingly. This is the application method of analog input and output.
