Performance Automation Opc

Improving Performance with OPC Tags in Automation Systems

In automation, performance delays can lead to inefficiencies, especially when dealing with real-time systems that require quick feedback loops. If you’ve ever experienced lag in your OPC (OLE for Process Control) data communication, you’re not alone. Many users of PC-based automation software, such as Think’n’Do by Phoenix Contact, face similar challenges. One common scenario involves the lengthy process of reading and writing tags to a PLC (Programmable Logic Controller)—where performance should ideally be in the order of milliseconds but can stretch to several seconds. Let’s explore how to identify and mitigate these performance issues effectively.

Identifying the Problem

In your case, the sequence of operations you outlined seems to indicate significant delays in communication between your automation software, OPC server, and PLC. The anticipated processing time should be around 130ms according to your calculations, but the actual performance lags at approximately 6 seconds. This discrepancy raises questions about how your OPC client is configured and whether the communication settings are optimized.

Factors to Consider

  • OPC Client Configuration: The default settings can set refresh intervals too high (e.g., 1s or even 5s), contributing to delays in data retrieval and command execution.
  • OPC Server Limitations: The server itself may impose restrictions on the frequency of data updates, impacting how promptly data can be sent or received.
  • Read/Write Modes: The asynchronous or synchronous nature of your reads and writes can drastically impact how data flows between the client, server, and PLC.

Solutions to Improve Performance

1. Examine OPC Client Subscription Settings

First, review how your OPC client is configured to pull data from the server. When subscribing to a data group, pay close attention to the refresh rate settings. Lowering the refresh rate can significantly improve responsiveness by ensuring your client checks for updates more frequently.

Steps to Adjust Settings:

  • Access your OPC client configuration.
  • Locate the group settings for the subscribed tags.
  • Set a refresh rate that is adequate for your application—aim for lower than default if possible.

2. Test with Alternative OPC Clients

If you suspect the hiccup may lie within the Think’n’Do software, a good practice is to test your OPC server with a different client. This confirms whether the issue is client-side or related to the PLC/server setup.

Recommended OPC Clients:

  • OPC Quick Client: Available in the TOP Server demo from Toolbox OPC, this robust client allows you to browse tags and examine their data and performance metrics.
  • OPC Data Spy by ICONICS: Another reliable choice, you can find it at ICONICS.

3. Focus on Read/Write Implementation

Understanding the methods of reading and writing data can aid in performance tuning. You can choose between:

  • Asynchronous Reads/Writes: These can allow your application to continue processing while waiting for data, which may result in improved overall throughput of the system.
  • Synchronous Reads/Writes: Though this method may be simpler, it can lead to bottlenecks if one operation takes longer than expected.

Using a combination of best practices, you can achieve optimal configuration that caters to the speed requirements of your automation setup.

4. Monitor and Analyze Response Times

After making changes to your configuration, continuously monitor the response times. Most OPC clients provide timing information that will help you diagnose whether the adjustments you’ve made yield positive results in performance.

Conclusion

Optimizing the performance of your OPC tags can enormously enhance your automation systems’ effectiveness. By adjusting settings in your OPC client, testing with alternative clients, and carefully considering your read/write methods, you can identify the root causes of delays and significantly reduce processing times. The right configuration not only ensures your automation operates within expected time frames but also bolsters productivity across your entire operation.

If you’re encountering sluggish performance in your automation projects, take these steps to troubleshoot and upgrade your setup; it’s likely to lead to smoother, more efficient operations in the long run.