← All project packs

Automated test bench with Raspberry PLC

Standards-based fuse testing — power dissipation, non-fusing and fusing sequences — with a SCPI-controlled power supply, precision current acquisition and fail-safe interlocks.

Runs on: Raspberry PLC 19R — Python 3 scripts (Linux PLC).

The application

A fuse manufacturer needed to automate its routine testing. A Raspberry PLC 19R orchestrates the whole bench: it drives a 220 A programmable power supply over SCPI, calibrates the test current in a closed loop, measures shunt current and voltage drop with an auto-ranging differential ADC, and runs the three standard test sequences with safety interlocks (emergency stop, micro-fuses, signal beacons). The operator works on a touch GUI and every test produces its own report.

Architecture

• Programmable power supply controlled over SCPI via USB-serial
• Closed-loop current calibration (50 ms, ±0.1 A)
• ADS1015 differential ADC over I2C with automatic gain
• PD / non-fusing / fusing test sequences with standards-based criteria
• Fail-safe interlocks + signal beacons + TXT report per test

Bill of materials

• Raspberry PLC 19R — Industrial Shields controller
• Programmable power supply 0-5 V / 0-220 A (SCPI) — current injection
• ADS1015 ADC + 60 mΩ shunt — precision measurement
• DS18B20 1-Wire probe — ambient test temperature
• Signal beacons + emergency stop — machine safety

What is in the pack

• ads1015-differential-adc-autogain.py
• closed-loop-current-calibration.py
• ds18b20-1wire-sensor.py
• fuse-test-sequences.py
• safety-interlocks-emergency-stop.py
• sorensen-scpi-power-supply-control.py
• tkinter-gui-beacons-relays.py
• txt-test-reports.py
• Bill of materials + README