# Process Diagnostics

## What It Is
Process diagnostics is the structured interpretation of operating symptoms, plant signals, derived indicators, and process context in order to understand what is happening on an extrusion or compounding line.

## Why It Matters
Most production failures do not begin as a single alarm. They emerge as drift across feeding, torque, pressure, temperature, venting, and quality behavior. Diagnostics must therefore connect symptoms to underlying process logic.

## Core Variables
- torque
- die pressure
- melt temperature
- feeder behavior
- vacuum level
- throughput
- specific energy
- alarm states
- run state

## Typical Industrial Problems
- symptom-only troubleshooting
- overreliance on average values
- misreading feeder instability as extruder instability
- misreading raw-material variation as machine failure
- missing the difference between measurable symptoms and hidden governing causes

## Engineering Approach
Diagnostics should combine:
- threshold logic
- trend logic
- process-state classification
- symptom-to-cause mapping
- human-readable recommended checks

The output should not be a black-box score. It should be a practical interpretation of likely process behavior.

## Related Docs
- [./problem-library.md](./problem-library.md)
- [./industrial-intelligence.md](./industrial-intelligence.md)
- [./extrusion-intelligence-system.md](./extrusion-intelligence-system.md)