What is the difference between PI ACE and AF Analytics?
What is the difference between PI ACE and AF Analytics?
PI Advanced Computing Engine (ACE) and PI AF Analytics both perform server-side calculations, but they differ significantly in architecture and capability.
PI ACE (Legacy)
- Writes custom calculations in VB.NET or C# as compiled DLLs.
- Runs on a dedicated ACE server.
- Full .NET framework access — can call external APIs, databases, etc.
- End of life: OSIsoft/AVEVA has deprecated ACE. No new development.
- Complex deployment: compile, deploy DLL, register, restart service.
PI AF Analytics (Current)
- Writes calculations using AF expression syntax in PI System Explorer.
- Runs on the PI Analysis Service.
- Expression-based (no compiled code) — easier to manage and audit.
- Supports rollups, event frame generation, and conditional logic.
- Actively supported and enhanced by AVEVA.
Comparison
| Feature | PI ACE | AF Analytics |
|---|---|---|
| Language | C#/VB.NET | Expression syntax |
| Deployment | Compile & deploy DLL | Configure in PSE |
| External access | Yes (databases, APIs) | No |
| Maintenance | High | Low |
| Support status | Deprecated | Active |
| Learning curve | High (development skills) | Medium |
Migration Path
Most ACE calculations can be migrated to AF Analytics expressions. For ACE calculations that call external systems, alternatives include:
- PI Integrator + external processing
- Custom services using AF SDK
- Azure Functions or AWS Lambda triggered by event frames
Recommendation
Always use AF Analytics for new calculations. Only keep ACE if you have complex external integrations that can't be replicated otherwise.
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