The Meaning of Siemens PLC Order Numbers

The order number of Siemens PLC is an important code for identifying the product model, functions, and characteristics, 

and its structure follows specific rules. Taking the **S7 series PLC** (such as the order number starting with 6ES7) as an 

example, the following is an analysis of its meaning:

 I. Basic Structure of the Order Number

Taking **6ES7 321-1BH01-0XA0** as an example, it is decomposed as follows:

```

6ES7  3  2  1  - 1B  H  01  - 0XA0  

|  |  |  |   |  |   |    |____ Suffix (place of origin, special functions)  

|  |  |  |   |  |____ Version number  

|  |  |  |   |________ Input/output point number and type  

|  |  |  |____________ Module function level  

|  |  |________________ Input/output type (digital/analog)  

|  |____________________ Module type (CPU/DI/DO, etc.)  

|_______________________ PLC series (S7/S5)  

_________________________ Automation system series  

```

 II. Detailed Analysis of Each Part

1. Automation System Series (First 3 Digits: 6ES)

- **6ES**: A fixed prefix indicating the Siemens automation system (such as PLC, drive, etc.).

2. PLC Series (4th Digit: 7)

- **7**: S7 series (mainstream PLC series);

  **5**: S5 series (older model).

3. Sub-series (5th Digit: 2/3/4/1/5)

- **2**: S7-200 series (small PLC, discontinued and replaced by S7-1200);

  **3**: S7-300 series (medium-sized PLC);

  **4**: S7-400 series (large PLC);

  **1**: S7-1200/S7-1500 series (new generation of small/medium-sized PLC);

  **5**: S7-1500 series (high-performance type).

4. Module Type (6th Digit: 1/2/3/4/5)

- **1**: CPU module;

  **2**: Digital input/output (DI/DO) module;

  **3**: Analog input/output (AI/AO) module;

  **4**: Communication module;

  **5**: Function module (such as high-speed counting, positioning module).

5. Input/Output Type (7th Digit, for Digital Modules)

- **1**: Input (DI);

  **2**: Output (DO);

  **3**: Input/output hybrid (DI/DO).

6. Function Level, Voltage Type and Number of Points (8th-9th Digits: 1B/H)

- **Function Level** (8th digit, for digital modules):

  The larger the number, the stronger the function (such as 1, 2, 3).

- **Voltage Type** (9th letter, for digital modules):

  - **B**: DC 24V (transistor output);

  - **H**: Relay output;

  - **F**: AC 120/230V (AC input/output).

- **Number of Points** (9th letter, for digital modules):

  - **H**: 16 points;

  - **L**: 32 points;

  - **F**: 8 points;

  - **D**: 4 points;

  - **B**: 2 points.

7. Version Number (10th-11th Digits: 01)

- It represents the hardware version. For example, **01** is version 0.1, **02** is version 0.2, and **23**

 is version 2.3.

  **Rule**: The larger the last digit, the newer the version, and it is usually backward-compatible (for example,

 version 03 can replace version 02).

8. Suffix (Last 4 Digits: 0XA0)

- **Place of Origin**:

  - **0XA0**: Originally produced in Germany;

  - **0XA8**: Produced in China (CN series, only sold in China, and the CPU has a "CN" mark).

- **Special Functions**:

  - **X**: Fixed placeholder;

  - **A0**: No special functions;

  - **B0**: With diagnostic function.

III. Example Analysis

Example 1: 6ES7 221-0BA23-0XA0

- **6ES7**: S7 series;

- **2**: S7-200 series;

- **2**: Digital input module;

- **1**: Input (DI);

- **0BA**: DC 24V, 2-point input;

- **23**: Version 2.3;

- **0XA0**: Produced in Germany, no special functions.

 Example 2: 6ES7 314-1AG13-0AB0

- **6ES7**: S7 series;

- **3**: S7-300 series;

- **1**: CPU module;

- **1AG**: High-performance CPU, relay output;

- **13**: Version 1.3;

- **0AB0**: Produced in Germany, with diagnostic function.

 IV. Precautions

1. **Differences Among Different Series**:

   The order number structure of S7-1200/S7-1500 is slightly simplified (such as **6ES7 121-1AE10-0XB0**), 

and the latest selection manual should be referred to.

2. **Module Replacement**:

   Different version numbers (such as 02→03) are usually compatible, but the hardware configuration needs to be 

updated in the programming software (such as STEP 7).

3. **Serial Number and Order Number**:

   - **Order Number**: Model identification (the same for the same product);

   - **Serial Number**: Unique code (such as **S V-######**), used to query the production date (Siemens official

 tools are required).

V. Query Tools

- **Siemens Industrial Support Center**: Enter the order number to directly query the product details ([Click to visit]

(www.transformerandswitchgear.com  ).

- **Selection Manual**: Obtain the latest and most detailed order number rules and module parameters.

Through the above analysis, the type, function, and place of origin of the PLC module can be quickly identified,

 which helps with model selection and troubleshooting. 

It should be noted that the website [Click to visit](www.transformerandswitchgear.com  ) you provided may be incorrect. 

The official website of Siemens Industrial Support Center is You can correct it according to the actual situation.