---
alias: tutorials-create-sampling-pattern
title: Creating a Sampling Pattern
description: "Create a sampling pattern using manual, system, or rule-based evaluation"
---

# Creating a Sampling Pattern

A [[user-guide-sampling-pattern-page|Sampling Pattern]] defines which **Sub-Materials** are sampled and in what sequence during a **Step**. It supports [[user-guide-manage-sampling|In-Step Sampling]], configurable at the **Step** level, either alone or alongside a **Sampling Plan**.

Example: sample wafers `2`, `6`, and `10` of a 25-wafer **Material** lot.

## How to Create a Sampling Pattern

In the **Business Data** section, select the **Sampling Pattern** entity.

![Screenshot showing the Sampling Pattern entity in the Business Data area.](../images/sampling_27.png)

Select **New** to create a new **Sampling Pattern**.

![Screenshot showing the action used to create a new Sampling Pattern.](../images/sampling_28.png)

Provide a **Name**, **Type**, and optionally insert a **Description**.

In **Evaluation**, select an **Evaluation Type** that matches the purpose of the **Sampling Pattern** in the real use case. The available options are Manual, Rule, and System, and each option determines how the Sampling Pattern is executed. The differences between these Evaluation Types are explained in the sections below.

![Screenshot showing the general data step of the Sampling Pattern wizard.](../images/sampling_29.png)

![Screenshot showing the Evaluation Type options for a Sampling Pattern.](../images/sampling_30.png)

### Manual

For scenarios where specific **Materials** in the container need to be selected, set the **Evaluation Type** to **Manual**.

In the **Manual** evaluation type, you must identify the desired sampling positions in **Selection**.

![Screenshot showing manual selection fields in a Sampling Pattern.](../images/sampling_31.png)

**Selection Format** is the predefined method used by Critical Manufacturing MES to sample specific **Materials** at specific positions. Specify the **Container** and **Position** for each **Sub-Material** by using a structured text format.

![Screenshot showing the selection format used for manual sampling definitions.](../images/sampling_32.png)

#### Format Overview

* Each sampling entry is written as `Container:Position`.
* Multiple entries are separated by semicolons (`;`): `C:1,R:1;C:Right-1,R:Bottom+2;C:2,A:1`

#### Container Definition

* The **Container** identifies which container the **Sub-Material** comes from.
* Containers are referenced by index using `C:<name>`.

!!! tip
    If the Material lot arrives at the Step in only one Container, you do not need to specify the container. Example: `R:5;R:2;R:3`

#### Position Definition

* The **Position** defines the location of the **Sub-Material** within the **Container**.
* There are two types of positions:
    * **Absolute Position (`A`)** - references a fixed position index. Example: `A:1`.
    * **Absolute Position (`A`)** - does not use **Top** or **Bottom** references.
    * **Relative Position (`R` or `P`)** - references position relative to container boundaries such as **Top** or **Bottom**. Example: `R:1`, `R:Bottom+2`, or `R:Right-1`.
    * **Relative Position (`R` or `P`)** - both `R` and `P` can be used to indicate relative positioning.

![Screenshot showing a manual sampling selection example.](../images/sampling_33.png)

#### Example Breakdown

| Sampling Entry | Container Reference | Position Reference | Explanation |
| --- | --- | --- | --- |
| `C:1,R:1` | Container 1 | Relative position 1 | Selects position 1 from the first Container alphabetically |
| `C:2,A:1` | Container 2 | Absolute position 1 | Selects the first absolute position from the second Container |

Table: Sampling selections

For more information about how to configure **Evaluation Type Manual**, go to [[user-guide-create-sampling-pattern]] and [[user-guide-sampling-pattern-page]].

### System

For scenarios where **Materials** in the **Container** need to be selected according to a predefined system in Critical Manufacturing MES, set the **Evaluation Type** to **System**.

![Screenshot showing the System evaluation type in a Sampling Pattern.](../images/sampling_34.png)

By selecting **System** as the **Evaluation Type** of a **Sampling Pattern**, additional fields become available for configuration:

* **Source**
* **Count**
* **Selection**
* **Sequence**

#### Example

| Field | Example Configuration | Explanation |
| --- | --- | --- |
| Source | Lot of processed wafers (25 wafers) | The system samples from the **Materials** produced in the lot, according to the **Material Form**. Examples include wafers for the semiconductor industry and panels for SMT. |
| Count | 20% (percentage) | Critical Manufacturing MES automatically selects 20% of the wafers in the lot for inspection. For a lot of 25 wafers, 5 wafers will be sampled. The defined **Count** can also be a fixed number. |
| Selection | Spread | The system distributes the samples evenly throughout the lot to ensure good process coverage. |
| Sequence | TopDownLeftRight | Sampling begins from the top-left wafer and proceeds row by row, ensuring consistent traceability in the lot layout. |

Table: Evaluation Type configuration fields

Critical Manufacturing MES automatically selects 5 wafers, evenly spaced across the lot, starting from the **Top-Left** position. This configuration ensures balanced inspection coverage without manual intervention.

For more information about how to configure **Evaluation Type System**, go to [[user-guide-create-sampling-pattern]] and [[user-guide-sampling-pattern-page]].

### Rule

For scenarios where **Materials** in the container are not selectable using a **Manual** or a **System** **Evaluation Type**, set this property to **Rule**. For more information, see [[user-guide-create-rule]].

Example: 3 wafers must be selected, but from time to time, **Material** lots arriving at the **Step** only have 1 or 2.

![Screenshot showing a rule-based Sampling Pattern configuration.](../images/sampling_35.png)

!!! note
    A [[user-guide-create-rule|Rule]] with the scope `SamplingSelection` from the [[rulescope-lt]] lookup table must be created in advance.

For more information about how to configure the **Evaluation Type** as  **Rule**, go to [[user-guide-create-sampling-pattern]] and [[user-guide-sampling-pattern-page]].