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CASE STUDY

Cut-to-Length Line Control System Upgrade

CompactLogix PLC, C-More HMI & Yaskawa VFD Upgrade for an HVAC Fabrication Line

The Challenge

An HVAC equipment manufacturer needed to replace aging relay-based controls on a cut-to-length fabrication line — eliminating manual counting, adding batch programming, and connecting the machine to the engineering office.

• No programmable batch capability — operators were required to manually count and measure each cut, creating throughput bottlenecks and opportunities for error
• Obsolete control hardware with no vendor support, increasing downtime risk and making spare parts difficult to source
• Feed roller positioning and material straightening that relied on fixed, non-adjustable mechanical setups, limiting flexibility across material sizes
• No variable speed control on the feed drive, restricting the line's ability to handle different material gauges or optimize cycle times
• No network connectivity between the machine and the engineering office, requiring operators to receive job parameters verbally or by paper

The Solution

Logic Control Systems delivered a complete controls and mechanical upgrade — replacing the relay panel with a CompactLogix PLC, adding a C-More HMI, installing a Yaskawa VFD on the feed drive, and connecting the machine to the office network for remote batch programming.

Mechanical Modifications

Before the electrical upgrade, LCS performed targeted mechanical improvements to improve material handling and cut accuracy:

• Feed rollers repositioned further aft to improve material support through the shear zone
• Floating straightening system installed with an entrance ramp and side rollers, accommodating material variation and reducing edge damage on entry
• Stabilizing roller added between the shear and feed rollers to reduce material bounce and improve cut accuracy
• New electric motor and gearbox mounted to the feed roller system, enabling VFD speed control

Control System

The new control system centers on an Allen-Bradley CompactLogix PLC with a C-More 10" color touchscreen HMI. A Yaskawa VFD provides variable speed control of the feed drive. A rotary encoder on the feed roller provides closed-loop cut-length feedback to the PLC. An Ethernet connection to the engineering office allows batch job parameters to be programmed remotely and downloaded to the machine.

Commissioning

LCS performed full on-site commissioning including:

• Full electrical I/O checkout — verifying all field devices, sensors, and control wiring against the AutoCAD schematics
• PLC program testing — step-by-step verification of cut sequence logic, batch execution, encoder feedback accuracy, and safety interlock functions
• VFD tuning — feed drive speed calibration across the material feed range, with ramp and decel parameters optimized for the mechanical system
• HMI screen validation — operator walkthrough of all screens, alarm pages, and batch entry workflows
• Four hours of operational training delivered to client operators, covering normal operation, batch job setup, alarm response, and manual override procedures

Encoder-based closed-loop length control and office-networked batch programming replaced manual counting and verbal job handoffs — improving cut accuracy and reducing per-job setup time.

Technology at a Glance

Results & Impact

• Batch cut programming from the office eliminates manual setup steps and reduces per-job configuration time.
• Encoder-based closed-loop length control improves cut accuracy and consistency across the full production range.
• Variable speed feed drive allows the line to be optimized for different material gauges without mechanical adjustments.
• Obsolete relay-based controls replaced with a modern, supportable Allen-Bradley platform with full vendor parts availability.
• New AutoCAD electrical schematics provide the client with accurate as-built documentation for future maintenance and troubleshooting.
• Operator training and documented control sequences reduce dependency on institutional knowledge and shorten new-operator onboarding time.
• Modernized control architecture positions the line for future integration with plant-wide networking or MES systems.

About Logic Control Systems

Logic Control Systems (LCS) is a Texas-based industrial automation integrator specializing in PLC programming, SCADA/HMI development, process control, electrical panel fabrication, commissioning, and remote automation maintenance. LCS serves clients across the U.S. in industries including food processing, fabrication, chemical, oil and gas, pharmaceutical, and water/wastewater.

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