Category map
CMMS vs EAM vs APM vs PdM vs MES
These categories overlap, but they do not own the same decision. Start with the operating question, then identify the system that records the answer and the system that triggers the next action.
The simple category map
Each category begins at a different point in the plant workflow. A product can cover several categories, but the buyer still needs to know which function is native and which function depends on an integration or partner.
- CMMS: plans and records maintenance work, labor, parts, inspections, and asset history.
- EAM: expands maintenance records into enterprise asset lifecycle, cost, risk, procurement, and governance.
- PdM: uses condition or operating data to estimate emerging failure and create useful lead time.
- APM: manages asset performance and risk across condition, reliability, strategy, and economic consequence.
- MES or MOM: manages production execution, quality, genealogy, scheduling, and plant performance.
- OEE and machine monitoring: explains availability, performance, quality, machine state, and production loss.
- ERP: owns financial, purchasing, inventory, order, and enterprise planning records.
How the systems should connect
A condition signal is not the finished outcome. The signal must be assessed, converted into planned work, completed by the right person, and checked against the original failure risk. Production context and cost records then show whether the action mattered.
- Sensors, controls, or historians create operating evidence.
- PdM or APM identifies the risk, failure mode, urgency, and recommended response.
- CMMS or EAM authorizes, schedules, and records the work.
- MES or machine monitoring shows production impact before and after the intervention.
- ERP records material, labor, purchasing, and financial consequences.
Where category overlap causes bad purchases
Overlap becomes expensive when a vendor demo makes a secondary capability look like the product's operational center. The buyer should test the whole workflow with real roles and systems, not accept a feature checklist.
- A CMMS with meter readings is not automatically a predictive-maintenance program.
- A diagnostic alert is not maintenance execution unless accepted work is tracked and verified.
- An OEE dashboard is not MES when genealogy, quality, scheduling, or production control is required.
- An integration claim is not a deployed workflow until ownership, data direction, latency, and exception handling are defined.
Use in diligence
Five questions to ask next
- Which decision are we trying to improve?
- Who owns that decision today?
- Where is the authoritative record after the decision is made?
- Which systems must exchange data, in which direction, and how quickly?
- What operating or financial result will prove the workflow improved?