Single Fieldbus Architecture

PLCCreator

Single Fieldbus Architecture

Select Section ...
1. Introduction
2. Use Cases
3. Creating a Single Fieldbus PLC
4. Main Rack Configuration
5. IO Lists
6. Examples

1.
Introduction

PLCCreator enables you to build PLC systems using 3 distinct architectural models:

  1. Single Rack
  2. Single Fieldbus
  3. Multiple Fieldbuses

The Single Fieldbus model features a PLC configuration with two or more racks interconnected through a single fieldbus network. Figure 1 below illustrates the basic structure of this architecture:

Figure 1: Principal Structure of the Single Fieldbus Architecture
Figure 1: Principal Structure of the Single Fieldbus Architecture

The architecture consists of:

  • AMain Rackcontaining theCPUmodule, fieldbus master module (shown in red and labeled "Master"), and IO modules
  • Remote IO rackswith fieldbus interface modules (blue, labeled "Local i") and additional IO modules

2.
Use Cases

The Single Fieldbus architecture is ideal for complex automation processes requiring signal distribution across multiple cabinets.

Configuration Flexibility

Remote IO racks can use different hardware platforms based on requirements like:
  • Ingress protection (IP rating)
  • Cabinet size constraints
  • Wiring density needs
  • Signal range specifications

Practical Example

Figure 2 shows a typical implementation with two cabinets:

  • Cabinet 1: Large main cabinet housing most IO signals
  • Cabinet 2: Compact enclosure for signals from a separate process area

System Architecture:

In this scenario:

  • The Main Rack (Cabinet 1) typically uses ET200MP (S7-1500) platform
  • The remote rack (Cabinet 2) often employs compact ET200SP for space efficiency
  • Both connect via Profinet protocol using the CPU-integrated master module
Figure 2: Use Case Example of Single Fieldbus Architecture
Figure 2: Use Case Example of Single Fieldbus Architecture

Explore this implementation in the example PLC "Cabinets_PLC" on the My PLCs page, or go directly to its Details page .

3.
Creating a Single Fieldbus PLC

Prerequisites

To create a Single Fieldbus PLC:

  1. Prepare either a signal IO list or device IO list
  2. Follow the Create PLC with PLCCreator guide
  3. Make sure you select "Single Fieldbus Architecture" on the PLC Architecture page

The remaining process is automated as described below.

Generation Process

When you click "Generate" on the Generate page, PLCCreator generates:

  • One rack per unique "Hardware Platform"-"Group" combination from the uploaded IO list
  • Within each rack, the IO modules are created following Single Rack architecture rules.

    These IO modules contain the signals that have combinations for "Hardware Platform"-"Group" from 1

Requirements

Each unique group within the "Hardware Platform" - "Group" combinations must be registered on the My Groups page

Figure 3 illustrates the PLC creation process from an IO list:

Figure 3: Creation of Single Fieldbus PLC from the IO List
Figure 3: Creation of Single Fieldbus PLC from the IO List

Naming Convention

Remote racks follow this naming pattern:

Rack_"Group_Name"_"X"

  • Group_Name: The group whose signals belong to this rack
  • X: Incremental number for racks within the same group

Use Case Implementation

For the use case inSection 2, configure your IO list columns as:

  • Cabinet 1 signals: Hardware Platform = "ET200MP", Group = "Cabinet1"
  • Cabinet 2 signals: Hardware Platform = "ET200SP", Group = "Cabinet2"
Figure 4 illustrates this configuration. Note: Signal names, descriptions, and types shown are generic examples for demonstration purposes.
Figure 4: Generic Signal IO List for the Use Case Example PLC
Figure 4: Generic Signal IO List for the Use Case Example PLC

Figure 5 demonstrates the PLC creation process from this IO list:

Figure 5: Creation of PLC based on the IO List for the Use Case Example
Figure 5: Creation of PLC based on the IO List for the Use Case Example

After importing the .aml file into Siemens TIA Portal, the network view appears as shown in Figure 6:

Figure 6: Siemens TIA Portal Network View
Figure 6: Siemens TIA Portal Network View

4.
Main Rack Configuration

Before generating your PLC on the Generate page, you must designate theMain Rackthat will contain the CPU module.

Figure 7: Main Rack Configuration Interface
Figure 7: Main Rack Configuration Interface
This designation was previously indicated with icon in Figure 3

From all generated racks, only one can be designated asMain Rack, the rest are automatically treated as remote IO.

1. Select Main Rack Type

Choose between:

Standard Rack

  • Default selection
  • CPU and IO modules for the Main Rack Group in single rack
  • Lower hardware cost
Figure 1

Standalone CPU

  • CPU in separate rack without IO
  • IO modules in remote IO rack(s) only
  • Better scalability, reliability and operational efficiency
Figure 9

If you select "Standalone CPU", the configuration of theMain Rackis completed.

2. Select Main Rack Group - for Standard Rack only

ChooseMain Rack Groupfrom the selection list, Figure 8

This list is created from thegroups, derived from unique "Hardware Platform"-"Group" pairs in the uploaded IO list, with "Hardware Platform" matching the CPU hardware platform configured on the CPU Data page.

This means the CPU module will be installed in the rack containing IO modules needed to wire the signals that have selected Main Rack Group.

Use Case Configuration

For theuse caseshown earlier:

  1. Select "Standard Rack" as the rack type.
  2. Under "Main Rack Group" , select "Cabinet1":
    Figure 8: Main Rack Group Selection
    Figure 8: Main Rack Group Selection

    Note: Group "Cabinet2" is unavailable because its hardware platform (ET200SP) does not match the CPU hardware platform (ET200MP) configured on the CPU Data page.

This ensures the Main Rack contains signals for Cabinet 1.

Standalone CPU Scenario

If no compatible hardware platform exists in your IO list, only the "Standalone CPU" option will be possible. The architecture adapts as shown in Figure 9:

Figure 9: Architecture with Standalone CPU
Figure 9: Architecture with Standalone CPU

6.
Examples

You can find following examples for Single Fieldbus architecture on My PLCs page, together withCabinets_PLCfrom2. Use Casessection: