OpenPLC on Raspberry Pi: Step-by-Step Setup Tutorial

Turn a $50 Raspberry Pi into a working PLC. Full path from blank SD card to running ladder logic with GPIO acting as digital I/O and a Modbus TCP client reading the values.

Beginner-friendly~45 minutesUpdated 2026

What you'll need

• Raspberry Pi 4 (any RAM size) or Raspberry Pi 5
• microSD card, 16 GB or larger, Class 10
• USB-C power supply (3 A for Pi 4, 5 A for Pi 5)
• Ethernet cable (recommended) or Wi-Fi credentials
• A development PC with the OpenPLC Editor installed
• Optional: relay HAT or external 24 V interface board to drive industrial loads safely

Pi GPIO is 3.3 V logic. Do not wire it directly to 24 V industrial signals — use an opto-isolator board, relay HAT, or a Pi-compatible PLC interface like PiXtend, RevPi, or Sequent Microsystems' industrial HATs.

Step 1: Flash Raspberry Pi OS Lite

Download Raspberry Pi Imager from raspberrypi.com/software.
Insert your microSD card. In Imager, choose Raspberry Pi OS Lite (64-bit).
Click the gear icon to set hostname, enable SSH, set username/password, configure Wi-Fi if not using Ethernet.
Write the image. Eject and insert into the Pi.

Step 2: Boot and update

ssh pi@openplc-pi.local
sudo apt update
sudo apt full-upgrade -y
sudo reboot

Step 3: Install OpenPLC Runtime

sudo apt install -y git
git clone https://github.com/thiagoralves/OpenPLC_v3.git
cd OpenPLC_v3
./install.sh rpi

The installer takes 5–15 minutes. When it finishes, the OpenPLC web interface is at http://openplc-pi.local:8080, default credentials openplc / openplc.

Step 4: Configure GPIO as PLC I/O

Log into the OpenPLC web interface, click Hardware, select Raspberry Pi:

PLC address	Direction	Pi GPIO pin
%IX0.0 – %IX0.7	Digital input	GPIO 8, 7, 16, 20, 21, 26, 19, 13
%IX1.0 – %IX1.6	Digital input	GPIO 6, 5, 12, 11, 25, 9, 10
%QX0.0 – %QX0.7	Digital output	GPIO 2, 3, 4, 17, 27, 22, 23, 24
%QX1.0 – %QX1.6	Digital output	GPIO 18, 14, 15, 1, 0, 8, 7
%IW0 – %IW7	Analog input (over MCP3008 SPI ADC)	SPI bus, requires hardware

Step 5: Write your first ladder program

On your development PC, install OpenPLC Editor from openplcproject.com/runtime. New project → Ladder Diagram. Add a single rung that wires Input 0.0 to Output 0.0. Save. File → Generate program for OpenPLC Runtime.

Step 6: Upload and run

OpenPLC web interface → Programs → Upload Program.
Select your generated .st file.
Click Compile program; wait for "Compilation finished successfully".
Click Start PLC on the Dashboard.
Click Monitoring to see live tag values.

Step 7: Connect a Modbus TCP client

OpenPLC exposes its variables via Modbus TCP on port 502:

mbpoll -m tcp -a 1 -t 0 -r 1 -c 8 openplc-pi.local

For visual clients use qModMaster (cross-platform, free) or Modbus Poll (Windows). Both can read/write coils, discrete inputs, holding registers and input registers.

Where to go next

• Real I/O: pair the Pi with a relay HAT (Sequent Microsystems Home Automation HAT) to drive 24 V loads safely.
• Industrial Pi: upgrade to PiXtend or Revolution Pi for proper isolated I/O, DIN-rail mounting, CE/UL certification.
• Connect to SCADA: Ignition Maker Edition (free for non-commercial) connects to OpenPLC over Modbus TCP for full HMI graphics.
• Move to production: ladder logic ports cleanly to CODESYS Control or commercial PLCs — IEC 61131-3 portability is OpenPLC's main strength.