In my final thesis, I will present the design procedure of the input-output controller card, which will be used on automatic assembly lines for adjusting the lightning in image capture and adjusting and controlling the position of motors. It will be also able to read digital and analogue sensors and control some analogue and digital outputs.
The device is enabling various communications for the interaction with the outside world. The device is connected through RS-232 and RS-485 interfaces, which are considered to be slow, but nonetheless very reliable communications and therefore they are still being used in the industry. The device has also a faster ethernet interface. The RS-485 interface will be used for communication between devices, and it is connected to DIN lath, below the device. The device is powered with 24 V DC that takes power from the main electro box.
The first design step was to write down all the device specifications based on the needs of the company. Then we made the block diagram in order to plan the basic layout and position of the elements on the PCB. Next step was to select the elements, design the electric scheme and to deploy the elements on the printed circuits board using Altium Designer.
We carried out simulations of critical parts of the printed circuits board with LT Spice, which helped us in deploying and choosing the correct values for components.
The main PCB is controlled with microprocessor STM32F407. The additional microprocessor is a simpler and cheaper 8-bit STM microprocessor STM8S103K3 that operates as a user interface, for controlling the signal LED diodes and reading the buttons.
The program code was developed with the open source software System Workbench for STM32. To set the whole periphery we used the program STM32CubeMX.
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