CONSTRUCTION OF THE INPUT SIGNAL TRANSDUCER OF THE PLC USING ETHERNET

Abstract

Currently, the PLC (Programmable Logic Controller) is no longer stranger to human, their appearances in factories or companies have brought great benefits to us. However, regarding analog signal processing problems, PLC has got some limitations that there are very few analog signal inputs availble intergrated in the CPU. In fact, there are transforming modules for PLC, but they are high price, required to synchronize the source of use, complicated in the connection assembly process; therefore, in this article we will present the the input signal converter construction solution for PLC to communicate with sensors by different communication standards such as I2C, SPI, OneWire, Analog and create low- cost products while ensuring the systems works well and stable in industrial environment. Input signal conversion module uses Kit Arduino paired with PLC according to Ethernet standard (TCP / IP) in which the Arduino Kit is responsible for collecting signals from high- accuracy sensors (3.3V, 5V) then processing, calculating and transmitting data to the PLC (24V). By the above method, we can perform problems of the PLC with sensors such as temperature sensor (LM35, TMP36), humidity (DHT11, DHT12), light (BH1750), dust sensor (Sharp GP2Y10), RFID card (RFID-RC 522), etc.