In industrial automation projects, PLC software plays a critical role in system reliability, sustainability and ease of maintenance. Software that is not developed to standards leads to losses of time and money in troubleshooting, commissioning and revisions. Under the SANKOTEK Automation approach, a standard software architecture based on modularity, readability and sustainability is applied to PLC software.
In industrial automation projects, PLC software plays a critical role in system reliability, sustainability and ease of maintenance. Software that is not developed to standards leads to losses of time and money during troubleshooting, commissioning and revisions.
Under the SANKOTEK Automation approach, a standard software architecture based on modularity, readability and sustainability is applied to PLC software.
1. Software Architecture
PLC software is designed in a hierarchical, modular structure. The basic structure is set up as follows:
- Main program
Manages the overall flow of the system - Function blocks (FB)
Reusable, independent control structures - Functions (FC)
Mathematical and logical operations - Subroutines / tasks
Dedicated structures for specific operations
Each module is structured to perform a single function.
2. Naming Convention
- To improve readability and ease of maintenance, all variables and blocks are named according to a standard.
- Clear, understandable names consistent with technical terminology are preferred.
3. Programming Principles
- A modular programming approach is applied
- Repeated code is grouped into function blocks
- Complex logic is simplified
- A clear input/output structure is defined for each function
- Unnecessary use of latches and set/reset is minimized
4. Comments and Documentation
Every software project is documented to an adequate level:
- Network comments are added
- Critical functions are explained in detail
- Input/output lists are documented
- Version information and revision history are recorded
Comments make it easier for different users to understand the system.
5. Error Handling and Alarm Structure
Error handling in PLC software follows a standard structure:
- Errors are coded (error codes)
- An alarm structure integrated with SCADA/HMI is created
- On critical errors the system is put into a safe state
- Resets are carried out in a controlled way
- Error and alarm data are logged historically with trends, and system performance trends are tracked by analyzing this data.
6. Security and Authorization
- Critical operations are restricted by authorization
- Manual intervention modes are offered in a controlled way
- Emergency stop (E-Stop) scenarios are handled safely in the software
7. Testing and Commissioning
Before the software is commissioned, the following tests are carried out:
- Simulation tests
- I/O tests
- Scenario-based tests
- Fail-safe condition checks
All test processes are documented.
8. Versioning and Backup
- All projects are versioned
- Changes are recorded
- Current software and backups are stored in secure locations
Conclusion
PLC software standards are treated not just as code organization but as a critical engineering approach for the sustainability and operational efficiency of the system.
With these standards applied at SANKOTEK Automation, the aim is to build more reliable, scalable and manageable automation systems.
