---
alias: user-guide-chart-index
description: "A Chart represents statistical process control data, linked to parameters and rules for analysis"
---

# Chart

:lock: Chart.**Show**

## Overview

A **Chart** is an object that represents a Statistical Process Control (SPC) Chart.

!!! info
	SPC is a Critical Manufacturing optional module.

A **Chart** has a Chart Type, and is associated with a numeric **Parameter**.

A **Chart** can also have an associated set of **Rules** to check for violations and, in the case a violation is found, a **Protocol Instance** can also be opened automatically by the system. The system comes pre-configured with a set of [SPC Rules](spc-rules/index.md), which can be extended by the user.

To promote the re-usability of a single chart across different contexts (for instance across different **Resources**), each **Chart** is associated with a context information. The **Chart** Context Information defines the **Chart** keys (that uniquely identify a **Chart**) as well as the mandatory context, which needs to be collected when posting data to the **Chart**. Each unique combination of **Chart** keys makes up the Logical Chart within a **Chart**.

A Data Point consists of a sample of data (which may contain many readings) and it is always associated with a **Chart** and a Logical Chart within a **Chart**.

To allow the integration between **Data Collection** and SPC, two context resolution tables exist in the system:

* [StepChartContext](../../administration/tables/smart-tables/stepchartcontext.md) - maintained at the **Step** level.
* [ResourceChartContext](../../administration/tables/smart-tables/resourcechartcontext.md) - maintained at the **Resource** level.

!!! info
	The following tokens are exchanged between EDC and SPC: Facility, Material, MaterialType, Step, Resource, ProcessResource, Product, ProductGroup, and Flow.

## Tying Everything Together

```mermaid
graph LR
    A1[Parameter] --- Main[Chart]
    A2[Maintenance Activity] --- Main
    Main === L1[Logical Chart]
    L1 === L6[Data Point]
    L6 === L7[Data Point Context]
    L6 === L8[Data Point Reading]
    L8 === L9[Data Point Violation]
    Main === L2[Chart Rule]
    L2 === L4["Rule (SPC)"]
    L2 === L5["Rule (SPC Action)"]
    L2 --- A3[Protocol]
    Main ==== L3[Chart Context Information]
    C1[Resource Chart Context] -.- Main
    C2[Step Chart Context] -.- Main

classDef mermaid_title color:#000, fill:#fafafa, stroke:#fafafa, stroke-width:0x, font-size:100%, font-weight:200;
classDef mermaid_start color:#000, fill:#fafafa, stroke:#fafafa, color:#fafafa, stroke-width:0x, font-size:100%, visibility: hidden;
classDef mermaid_businessdata color:#000, fill:#65CDE8, stroke:#65CDE8, stroke-width:0px, font-size:100%;
classDef mermaid_nonbusinessdata color:#000, fill:#B7DEE8, stroke:#B7DEE8, stroke-width:0px, font-size:100%;
classDef mermaid_entity color:#000, fill:#FB9F53, stroke:#FB9F53, stroke-width:0px, font-size:100%;
classDef mermaid_entitylinked color:#000, fill:#FCD5B5, stroke:#FCD5B5, stroke-width:0px, font-size:100%;
classDef mermaid_context color:#000, fill:#B9CDE5, stroke:#B9CDE5, stroke-width:0px, font-size:100%;
classDef mermaid_optional color:#000, fill:#B7DEE8, stroke:#65CDE8, stroke-width:1px, font-size:100%, stroke-dasharray: 5 5;
class Main mermaid_entity
class A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12 mermaid_businessdata
class L1,L2,L3,L4,L5,L6,L7,L8,L9 mermaid_entitylinked
class C1,C2,C3,C4,C5,C6 mermaid_context
class N1,N2,N3,N4,N5,N6 mermaid_nonbusinessdata

click Main "../../business-data/chart"
click A1 "../../business-data/parameter"
click A2 "../../business-data/maintenance-plan"
click A3 "../../business-data/protocol"
click A4 "../../business-data/flow"
click C1 "../../administration/tables/smart-tables/resourcechartcontext"
click C2 "../../administration/tables/smart-tables/stepchartcontext"
```

## Data Points

All posts to a **Chart** consist of a Data Point. A Data Point represents a sample unit and may consist of several reading. A Data Point can be:

* **Active** - by default, whenever a data point is posted.
* **Excluded** - if the data point has been marked as excluded.
* **Edited** - if it has been edited after being posted.
* **Removed** - if the data point has been marked as removed. A removed data point still remains in the database.

The SPC rules are only run when the data point is first posted. If the data point is edited or deleted afterwards, the SPC rules are not run again.
The following table lists the different behavior of the **Chart** depending on the data point Status:

| Data Point Status | Visible in Chart | Used for Histogram & Statistics | Considered in Rules | Used in Control Limits Re-calculation |
|------------------|---------|-------|------|------|
| Active | Yes | Yes | Yes | Yes |
| Removed | No | No | No | No |
| Edited | Yes | Yes | Yes | Yes |
| Excluded | Yes | No | No | No |

Table: Data Point Status

!!! info
	Because some SPC indicators depend on multiple SPC chart data point which can use variable specification limits and centerlines, the system uses the configuration `/Cmf/System/Configuration/SPC/MultipleDataPointStatiscs/CalculationMode` to define how the different values are handled. Possible values are **Average** (takes an average of all chart data point values) or **Last** (uses the values from the last chart data point).

!!! info
	SPC charts data points are oly processed by the Data Warehouse aggregation procedure after the number of hours defined in `/Cmf System/Configuration/SPC/DataWarehouseAggregationDelay` has elapsed.

## Sequence Of Steps

The necessary steps for correctly using a **Chart** are the following:

1. Create the **Chart**.

!!! info
	For more information, see the [SPC](../../../tutorials/modules/statistical-process-control/spc.md) tutorial.

{{ generate_index() }}