# Coating Line SPC

Spray Line 1 measures coating thickness, flow rate and line speed continuously. Instead of asking an operator to type those numbers in, Kanoa will read them from tags every five minutes and store each reading as a check.

That steady stream of samples is what **Statistical Process Control (SPC)** needs. A spec check asks "is this value inside its limits?" SPC asks "is the process behaving normally over time?" A process can be in spec and still drifting.

| | Specification limits | Control limits |
|---|---|---|
| Come from | Product, customer or engineering requirements | The process data itself, typically the mean ± 3 standard deviations |
| Answer | Is the product acceptable? | Is the process stable? |

In this section you will:

- Use attributes to read tag values, with one data source per asset.
- Build an automatic check sheet with a timed interval trigger.
- Analyze the samples in Check Details and apply SPC rules.