EPLAN Design Workflow
From Control System Requirements to Manufacturing Documentation
Electrical control panel design is not simply a matter of drawing a schematic.
A complete electrical design needs to translate the requirements of the machinery or process into documentation that can be used to manufacture, wire, test, commission and ultimately maintain the control system.
EPLAN provides an engineering environment for developing structured electrical documentation and managing the relationships between devices, connections, terminals and other project information.
The quality of the finished documentation, however, still depends on the engineering process behind it.
A good EPLAN workflow begins with understanding the application and progresses through system architecture, component selection, schematic development, terminal and cable planning, design review and final documentation.
This guide provides a practical overview of how an industrial control panel project can progress through an EPLAN electrical design workflow.
Define the Project Requirements
The design process should begin before EPLAN is opened.
The first step is understanding what the control system actually needs to do.
Project information may include:
Electrical supply.
Machinery or process requirements.
Motors and loads.
PLC requirements.
I/O.
Instrumentation.
Variable Speed Drives.
Safety requirements.
Industrial communications.
Operator controls.
Environmental conditions.
Customer standards.
Existing equipment and documentation should also be reviewed where the project involves a modification or control system upgrade.
The objective is to establish sufficient information to develop the electrical architecture before detailed schematics are created.
Develop the Control System Architecture
Once the requirements are understood, the overall control system architecture can be developed.
This establishes how the major electrical and automation elements relate to one another.
The architecture may include:
Incoming electrical supply.
Distribution.
Circuit protection.
PLC.
Remote I/O.
Motor control.
Variable Speed Drives.
Safety equipment.
HMIs.
Industrial networking.
Field instrumentation.
External system interfaces.
At this stage, engineers should also consider whether equipment will be contained within one control panel or distributed across several enclosures.
Developing the architecture first reduces the risk of detailed design decisions being made without considering the complete system.
Select the Control Panel Components
Once the electrical architecture has been established, suitable components can be selected.
Selection may include:
PLC hardware.
I/O modules.
Circuit protection.
Contactors.
Relays.
Power supplies.
Variable Speed Drives.
Safety equipment.
Network components.
Terminals.
Enclosures.
Component selection needs to consider more than the immediate electrical function.
Availability, standardisation, lifecycle, environmental suitability, heat generation, physical dimensions and future maintainability can all influence the decision.
The selected devices then become part of the structured EPLAN project rather than simply being represented as generic symbols.
Establish the EPLAN Project Structure
Before detailed schematic development, the EPLAN project should be structured consistently.
A defined project structure makes documentation easier to navigate and maintain.
Depending on the project and company standards, this may include organisation around:
Functional areas.
Locations.
Control panels.
Electrical circuits.
Machine sections.
Equipment groups.
Document types.
Consistent naming and device identification are particularly important.
A PLC input shown on one drawing, for example, should be readily traceable to the relevant PLC hardware, terminal and field device.
Good project structure becomes increasingly valuable as the size and complexity of the automation system grows.
Create the Electrical Schematics
Detailed electrical schematics translate the control system architecture into the circuits required to manufacture the panel and connect the machinery.
Drawings may cover:
Incoming supply.
Power distribution.
Protective devices.
Control power.
PLC hardware.
Digital I/O.
Analogue I/O.
Motor circuits.
Variable Speed Drives.
Safety circuits.
Relays.
Field devices.
Industrial communications.
The schematic needs to communicate design intent clearly to panel builders, commissioning engineers and future maintenance teams.
It should therefore be created as engineering documentation rather than simply as a record of electrical connections.
PLC and I/O Design
PLC architecture forms a significant part of many EPLAN control system projects.
The electrical design may document:
PLC CPU.
Power supplies.
Digital inputs.
Digital outputs.
Analogue inputs.
Analogue outputs.
Communication modules.
Safety I/O.
Remote I/O.
Each signal needs to relate clearly to the equipment it represents.
For example, a motor feedback signal should be traceable between the PLC input, terminal and relevant field equipment.
Accurate I/O documentation also provides a useful foundation for PLC programming and Factory Acceptance Testing later in the project.
Terminal, Cable and Connection Planning
Control panel designs need to consider how the manufactured panel will connect to equipment in the field.
This involves more than simply placing terminals onto a drawing.
The design may need to consider:
Terminal numbers.
Terminal types.
Protective earth terminals.
Control wiring.
Power wiring.
Cable cores.
Shielding.
Field devices.
Cable destinations.
Spare terminals.
A logical terminal arrangement can make panel manufacture, installation and future maintenance significantly easier.
Where appropriate project data is maintained within EPLAN, terminal and connection information can also contribute to automatically generated project documentation.
Device Data and Automated Documentation
One of the benefits of structured electrical engineering software is the ability to use project information for more than the schematic itself.
Depending on the EPLAN configuration and quality of the project data, engineering information can support generation of documentation such as:
Parts lists.
Device lists.
Terminal diagrams.
Cable information.
Connection information.
PLC-related documentation.
Project reports.
This can reduce the need to manually recreate the same information across multiple documents.
However, automated documentation is only as reliable as the underlying project data.
Incorrect device properties or inconsistent project structure can simply automate the production of incorrect information.
Engineering review therefore remains essential.
Review the Design Before Manufacture
Electrical drawings should be reviewed before being released for panel manufacture.
The review should consider both electrical correctness and practical manufacturability.
Questions may include:
Are component ratings appropriate?
Does the PLC architecture match the I/O requirements?
Are protective devices correctly specified?
Are terminals suitable and accessible?
Are component references consistent?
Are field connections clear?
Have design changes been incorporated?
Is sufficient space available?
Has heat generation been considered?
Is the documentation complete enough for manufacture?
The design should also be reviewed against relevant project requirements and applicable standards.
Depending on the application, these may include BS EN IEC 61439 and BS EN 60204-1.
Release the Design for Panel Manufacture and FAT
Once the design has been reviewed and approved, controlled documentation can be released for manufacture.
The panel builder should be working from an identifiable revision rather than an uncontrolled collection of drawings.
During manufacture, queries or practical issues may result in design changes.
These changes need to be controlled so that the engineering documentation continues to reflect what is actually being built.
Once manufacture is complete, the drawings also provide an important reference during Factory Acceptance Testing.
The FAT can verify areas such as:
Components.
Wiring.
Terminals.
PLC I/O.
Electrical functionality.
Equipment identification.
Any modifications arising during FAT should feed back into the controlled project documentation.
Commissioning and As-Built Documentation
The design process does not necessarily finish when the control panel leaves the workshop.
Installation and commissioning can identify changes required to accommodate actual site conditions.
These may include:
Field wiring changes.
Instrument modifications.
Terminal changes.
Component substitutions.
I/O changes.
Additional devices.
Design corrections.
These modifications should be incorporated into the final as-built documentation.
The as-built electrical drawings should represent the system that was actually installed rather than the design that originally left the engineering office.
Accurate as-built information becomes extremely valuable during future fault finding, maintenance and control system modernisation.
A small documentation change ignored during commissioning can become a significant troubleshooting problem years later.
Why a Structured EPLAN Workflow Matters
EPLAN can provide powerful tools for electrical engineering, but software alone does not create a good control panel design.
The engineering workflow determines whether the final documentation is accurate, structured and useful throughout the lifecycle of the automation system.
A strong process connects:
Requirements → architecture → component selection → schematics → terminals and connections → design review → manufacture → FAT → commissioning → as-built documentation.
Each stage should inform the next.
When that process is maintained correctly, the electrical documentation becomes more than a set of drawings used to build the panel. It becomes part of the long-term engineering record for the machine or control system.
Stratos uses EPLAN as part of its wider control panel design and automation engineering capability, allowing the electrical design to be developed alongside PLC, networking, drive and wider control system requirements.
Need Help with EPLAN Control Panel Design?
Good electrical documentation begins with good engineering.
The control system requirements, component selection, PLC architecture, terminals, field wiring and applicable standards all need to be considered before a control panel reaches manufacture.
Stratos provides EPLAN electrical design, industrial control panel design and manufacture, PLC programming and automation engineering, allowing the electrical documentation to be developed as part of the complete control system.
Speak to our engineers about EPLAN control panel design, electrical documentation or the development of your next industrial control system.
Frequently Asked Questions
What is EPLAN used for in control panel design?
EPLAN is used to develop structured electrical engineering documentation for control systems. Projects can include electrical schematics, devices, PLC hardware, terminals, connections and associated engineering information used during manufacture, commissioning and maintenance.
Is EPLAN only used to create electrical schematics?
No. Electrical schematics are a major part of the project, but structured EPLAN data can also support device information, terminal documentation, connection information, parts lists and other engineering reports depending on how the project is configured.
When should component selection take place in the EPLAN workflow?
Component selection should follow an understanding of the control system requirements and electrical architecture. Selecting components before the application is properly defined can result in equipment being specified that does not suit the complete system.
What are as-built electrical drawings?
As-built drawings represent the electrical system as it was actually manufactured, installed and commissioned. Changes made during panel manufacture, FAT or site commissioning should therefore be incorporated into the final documentation.
Can EPLAN documentation help with future control system upgrades?
Yes. Accurate electrical schematics, component information, terminals and I/O documentation can significantly improve the ability of engineers to understand an existing system when planning PLC migrations, control panel refurbishment or wider automation modernisation.