Programmable Logic Controllers (PLC) are an essential part of automated industrial production processes since their first implementation, so understanding the IEC 61131 standard and, above all, section three defines the programming languages allowed by PLCs take relevance over time. This work describes each of the programming languages described in IEC 61131-3. Additionally, it implements an automation system based on Structured Text with a Human Machine Interface (HMI). The plant is a temperature process with a classic control system developed using Matlab tools, such as System Identification, PID Tuner, and Simulink. For the HMI, was implemented the Codesys Group industrial automation process platform. The Simulink PLC Coder toolbox allows the strengthening of the connection between the control system and the HMI. This program generates the Structured Text of a control system developed in Simulink. For the analysis of results, the control behavior compared between Simulink and the system produced in Codesys Group obtained an error of less than 0.34 %.