Upgrading an automation and control cabinet is a strategic way to modernize industrial equipment, improve reliability, and add new capabilities—without completely replacing the system. Whether you’re updating a legacy system, improving safety, or adding connectivity, here’s how to plan and execute an effective upgrade.
Automation and Control Cabinet Upgrade Guide
1. Reasons to Upgrade
- Obsolete or unsupported PLCs, drives, or HMIs
- Inability to connect to modern networks (Ethernet/IP, Modbus TCP, etc.)
- Frequent faults or maintenance downtime
- Need for improved safety compliance (SIL/PL upgrades)
- Adding new machine features or expanding I/O
- Energy efficiency and better thermal management
2. Assessment & Planning
- Document existing system:
- Schematics, wiring diagrams, PLC programs, I/O lists, device tags
- Identify upgrade goals:
- E.g., replace old PLC (SLC, Siemens S5), add SCADA support, retrofit VFDs
- Evaluate space and thermal limits of existing cabinet
- Backup all software and programs before any changes
3. Common Upgrade Components
| Component | Old → New Options |
| PLCs | Allen-Bradley SLC → CompactLogix / Siemens S5 → S7-1500 |
| HMIs | Monochrome → Touchscreen with Ethernet |
| Drives | Basic VFD → Smart drive with PID, energy-saving modes |
| Relays/Timers | Mechanical → Solid-state or PLC-integrated |
| Power Supplies | Linear → Switching with diagnostics |
| Network | Serial RS-232/485 → Ethernet/IP, Profinet, Modbus TCP |
| Safety Devices | Hardwired → Safety PLCs, safety relays, light curtains |
4. Upgrade Process Steps
- Survey and reverse-engineer if original documents are missing
- Design new schematics using AutoCAD Electrical or EPLAN
- Select modern equivalents for legacy parts
- Create a migration strategy (phase-wise vs. full swap)
- Order new components, including wiring, terminals, breakers
- Build or retrofit the cabinet:
- Remove old gear
- Install new DIN rails, wiring ducts, cable trays if needed
- Wire new components, label thoroughly
- Load or convert PLC/HMI programs
- Test all I/O and network connections
- Document the final installation
5. Post-Upgrade Benefits
- Increased reliability and diagnostics
- Remote access and data logging
- Reduced unplanned downtime
- Improved safety compliance (with PL/SIL validation)
- Energy savings and faster troubleshooting
6. Key Considerations
- Check compatibility of existing sensors/actuators with new hardware
- Watch for grounding and shielding in high-speed networks
- Validate control logic conversion (ladder to structured text or vice versa)
- Ensure proper panel cooling for added components
- Meet all updated code standards (UL508A, IEC 60204-1, NFPA 79)