PLC Performance Optimization: Reducing Redundant Scanning and Lowering CPU Load by 35%!

📚 Estimated reading time: 8 minutes

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This article will detail the core techniques for PLC performance optimization, helping you significantly reduce CPU load.

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– Is your PLC program often experiencing long scan cycles?

– How to solve high CPU load issues?

– How to avoid low program execution efficiency?

– Want to know how industry experts optimize PLC performance?

⚠️ Industry Pain Points

1. 1. Long program scan cycles lead to slow system response

1. 2. High CPU load affects device stability

1. 3. Redundant scanning wastes system resources and reduces program execution efficiency

🎯 Key Points of This Article

1. 1. System performance improvement of over 35%

1. 2. Detailed scan cycle optimization plan

1. 3. Optimization techniques for mainstream PLC brands

▎ Step 1: Program Structure Optimization

Rationally planning the program structure is the first step in optimizing PLC performance. By optimizing the program architecture, execution efficiency can be significantly improved.

📋 Key Operations:

• Adoptmodular programming concepts

• Rationally dividefunction blocks, avoiding repeated calls

• Useinterrupt programs to handle high-priority tasks

💡 Expert Tip:

Place frequently executed code blocks at the front of the main program to reduce scan time.

▎ Step 2: Conditional Execution Optimization

By usingconditional execution control, avoid unnecessary scanning.

📋 Key Operations:

• UseEN/ENO to control function block execution

• Implementselective jumps to skip unnecessary program segments

• Rationally setscan conditions to reduce repeated calculations

⚠️ Note: Avoid excessive conditional statements, as they may create new performance burdens.

▎ Step 3: Data Access Optimization

Optimizingdata access methods can significantly enhance program execution efficiency.

📋 Key Operations:

• Uselocal variables instead of global variables

• Rationally usepointer addressing

• Optimizearray access methods

📊 Practical Application

A case study of PLC optimization in an automated production line:

• Before optimization: scan cycle 85ms, CPU load 78%

• After optimization: scan cycle 52ms,CPU load reduced to 43%

❓ Troubleshooting

Q1: How to identify redundant scanning in the program?

A1: Useonline monitoring tools to analyze program execution frequency and duration.

Q2: How to ensure program stability after optimization?

A2: Validate system stability throughloop testing andload testing.

💻 Brand Compatibility Points

• Siemens S7 Series: Supportsoptimized instruction sets, make good use of SCL language programming

• Mitsubishi FX Series: Focus oninterrupt program optimization, rationally use special registers

• Rockwell AB Series: Fully utilizeAOI instructions to optimize task scheduling

📝 Summary

1. 1. A rational program structure is the foundation of performance optimization

1. 2. Conditional execution control is key to reducing CPU load

1. 3. Continuous optimization and testing are essential for ensuring system stability