PLC Check-Weigher System

Hardware: Raspberry Pi 4B · Mitsubishi PLC (Type3E) · Check-weigher line
Author: Bibin VR

Real-time check-weigher data logger and report system for a Mitsubishi PLC production line. Monitors each item, logs weight and status, generates PDF batch reports, and instantly pushes them to a network PC via SMB.

Features

• Live PLC polling at 50 ms — captures every item (accept/reject/weight)
• PDF batch report generated automatically at end of each production run
• Instant PDF push to Windows/Mac shared folder via SMB (no software needed on the receiving PC)
• Live operations dashboard — weight gauge, batch stats, item feed in real time
• PDF report viewer with live auto-refresh (new reports appear without page reload)
• Systemd service — starts at boot, reconnects on PLC disconnect

Quick Start

# Install dependencies
python3 -m venv /home/pi/plc_env
source /home/pi/plc_env/bin/activate
pip install pymcprotocol flask reportlab
sudo apt install samba-client

# Start watcher (or install as systemd service — see procedure.md)
cd /home/pi/plc_checkweigher
python3 plc_watcher.py

# Start web interface
python3 web/app.py

Open http://<pi-ip>:8080 for the report viewer, /live for the dashboard.

PDF Push Setup

See procedure.md for full setup instructions including:

• Windows local user creation (avoids Microsoft account credential issues)
• macOS File Sharing configuration
• Email delivery via Gmail
• HTTP push using pdf_receiver.py

Project Layout

plc_checkweigher/
├── plc_watcher.py        # systemd entry — waits for PLC START
├── plc_reader.py         # per-item data collection + PDF trigger
├── plc_report.py         # PDF generation (ReportLab)
├── pdf_push.py           # instant PDF delivery to network PC
├── pdf_receiver.py       # optional HTTP receiver for target PC
├── plc_watcher.service   # systemd unit
├── procedure.md          # full setup & operating procedure
└── web/
    ├── app.py            # Flask server (port 8080)
    └── templates/
        ├── index.html    # report list with live SSE refresh
        └── live.html     # live operations dashboard

Configuration

Edit the top of each file:

| File | Key settings | |---|---| | plc_reader.py | PLC_IP, PLC_PORT | | plc_watcher.py | PLC_IP, PLC_PORT | | pdf_push.py | SMB_HOST, SMB_SHARE, SMB_USERNAME, SMB_PASSWORD | | web/app.py | REPORTS_DIR, PORT |