To improve system architecture performance with PLC programming, you need to apply the best practices and principles that can enhance the quality and efficiency of your PLC code and your system design. Modularization, optimization, testing, and documentation are all essential for this purpose. Modularization involves dividing your PLC code into smaller and reusable modules or functions that perform specific tasks or operations, making it easier to read, maintain, and debug. Optimization can be done by using appropriate data types, variables, operators, and instructions that can reduce the memory usage, scan time, and execution time of your PLC. Additionally, you can optimize your system design by using suitable hardware, software, networks, and protocols that can improve the throughput, latency, availability, and scalability of your system. Testing should be done with various methods and tools such as debugging, troubleshooting, verification, validation, and quality assurance in order to detect and correct any errors or faults. Documentation is also necessary in order to explain the purpose, structure, and logic of your PLC code and your system design. Documentation can help you understand, modify, maintain your PLC code and system design as well as communicate with other stakeholders.