A low-cost microcontroller-based PLC for industrial automation of a gold processing plant

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Most mining companies incur losses because of the improper automation of their gold extraction procedures. Some companies tend to rely on relay logic, a more cumbersome and inefficient automation method. This approach involves the manual control of the plant with relays and contactors. Another approach involves buying a Programmable Logic Controller from third-party companies. However, this method is very expensive and requires company-specific products to move. The paper discusses the successful design of a low-cost microcontroller-based Programmable Logic Controller (PLC). This PLC was designed as a cheaper approach for mining companies in Ghana. The design was initially implemented with the MKL25Z microcontroller but was later replaced with the Atmega128 due to the unavailability of the MKL25Z microcontroller as a result of a global chip shortage. The PLC was implemented on a Printed Circuit Board and can be programmed with any of the IEC 61131-3 standard programming languages for Programmable Controllers (Ladder Logic, Instruction List, etc.) using a open source software called OpenPLC which can supports the use of these languages on a microcontroller. Additionally, the PLC can communicate with a Supervisory Control and Data Acquisition (SCADA) system via Modbus IP, allowing for the SCADA system to monitor the states of the input and output devices, as well as control the field devices from the office.
Capstone Project submitted to the Department of Engineering, Ashesi University in partial fulfillment of the requirements for the award of Bachelor of Science degree in Electrical and Electronic Engineering, May 2022
gold ore processing, automation