03/25/2025
A roofing company in Williston, VT, reached out to me for help to repair their portable machine that forms standing seam panels. This machine, weighing approximately 2,000 lbs and transported on a trailer, utilizes sheet steel coils to produce on-site roofing panels. Manufactured around 2000, the machine is no longer supported by the manufacturer and the PLC controller had become obsolete. Furthermore, the provided wiring diagram proved inaccurate.
After researching the manufacturer and reaching out to them, I was able to obtaining a file and eventually a printout of the existing PLC program. I discovered that nearly half of the code was extraneous, likely remnants from previous machine updates. I selected a compatible, current-generation PLC based on an analysis of the existing control panel.
A test panel was constructed to simulate the machine's operational components, including the pendant, limit switches, and outputs. This allowed for thorough testing and development. Given the significant discrepancies in the original program and its incompatibility with the new PLC, a complete program rewrite was deemed necessary.
Extensive testing was conducted, with a focus on implementing robust safety features. Notably, the system was designed to ensure that in the event of a power interruption and restoration, the shear mechanism returns to its resting position, preventing unintended operation.
The updated PLC is now ready for customer pickup and installation. I will provide on-site commissioning support upon installation.
