Great question! When vendors promise 30% fewer breakdowns but want you to replace half your PLCs, you need to dig deeper than their marketing slides. Here's how to calculate the real ROI:
First, track your current costs for 6-12 months: unplanned downtime expenses, emergency repair costs, maintenance labor hours, parts inventory, and safety incidents. This gives you a baseline.
Then calculate the total investment: PLC replacement costs (half your units × $2,000-5,000 each), edge computing hardware, AI software licenses, installation labor, and training. Don't forget ongoing costs like maintenance and updates.
For savings, apply the 30% reduction to your actual breakdown costs, but also factor in: reduced emergency repairs (25-40% savings), lower parts inventory (15-25% savings), improved labor efficiency (35-45% of maintenance costs), and potential safety/compliance benefits.
Use this formula: ROI = (Annual Savings - Annual Costs) ÷ Annual Costs × 100%. For a more complete picture, calculate payback period (Investment ÷ Annual Savings) and 3-year ROI considering compounding benefits.
Most importantly, ask the vendor for case studies with similar PLC replacement scenarios and get a trial period to validate their 30% claim with your actual equipment before committing to the full hardware overhaul.