GNU ARM tools are available for programming the open source PLC. Seconds, minutes, hours, day, month, years, and centuryĢ56k bytes Flash memory for program and data storageĦ4k bytes SRAM for program and data storageĨk EEPROM for non-volatile storage, general-purpose useĪT91SAM7S256 32-bit ARM microcontroller from AtmelĬode is loaded via the USB or RS-232 ports using the on-chip boot loader or directly using the JTAG port Hardware Specification Power SupplyĢ4V DC – can be configured to operate from 12V to 24VĨ NPN open-collector (current sinking) outputs rated at 200mA eachĤ analogue inputs rated at 0V to 10V, 10-bit resolutionġ × USB device port, 1 × RS-232 port (TX and RX only), 1 × RS-485 port, 1 × JTAG debug port Open-source software C programming tools are available for programming the PLC. The internal microcontroller is directly accessible to the programmer.

Programming of the PLC can be done in C and C++. Small Open Source PLC Featuresįeatures include digital I/O, analogue inputs, RS-232 port, RS-485 port, USB device port, JTAG debug port, real-time clock (RTC) with battery backup, Flash memory, SRAM and EEPROM. The restored machine resulted in a cost savings for the owner as it was much cheaper to restore the machine than buy a new one. The machine pictured above was fitted with new electronics and pneumatic parts. Small Brick Open Source PLC Controlling a Densitron The PLC controls the pneumatic mechanisms for operating the machine, responds to button presses on the front panel, allows an operator to configure the machine using a keyboard and LCD, and prints test results to an RS-232 slip printer (bottom right). The image below shows the small brick open source PLC (top right of cabinet) used to control a machine that automatically measures the density of rubber samples. Computer I/O and communication expansion.Some applications that the OSPLC (Open Source PLC) can be used in: The other buttons are ignored by the program. The fourth input button stops all programs from running. One of three programs will run, depending on which input button is pressed. This video shows the Open Source PLC being demonstrated. All the source files for the small brick OSPLC are provided, including schematic diagrams so that you can build this project yourself or modify it.Įven if you do not wish to build the project, it serves as a useful reference design for anyone wanting to build a similar PLC project.

Open source plc ladder logic software