Recently, a friend working in industrial product procurement complained to me, “The software team is always complaining that the industrial PCs our company buys have poor real-time performance. What should I do?” This is a very common problem, especially in industries like industrial automation, robotics, PLC (Programmable Logic Controller), and PAC (Programmable Automation Controller), where real-time performance is often a mandatory requirement.
Today, let’s discuss how to scientifically evaluate the real-time performance of an industrial PC to help you avoid making the wrong purchase!
Which Industries Demand High Real-Time Performance from Industrial PCs?
In the industrial sector, the following product categories typically have strict requirements for real-time performance:
- Industrial Robots: Involve motion control and trajectory planning, which demand extremely high real-time capabilities.
- PLC/PAC: Require high-speed I/O response and precise logic control.
- Specialized Industrial Equipment: Such as CNC machines and semiconductor manufacturing equipment, which have stringent requirements for control accuracy and response speed.
- Industrial Bus Devices (e.g., EtherCAT/Profinet): Need to achieve high-precision synchronization.
These applications not only require industrial PCs to be stable, reliable, and powerful in computation, but they must also feature low latency and high real-time performance. Otherwise, it can lead to decreased control accuracy and even equipment failure.
Why is Real-Time Performance So Important?
Failure to meet real-time standards in an industrial PC can lead to a series of problems:
- For Industrial Robots: Excessive latency can cause deviations in motion trajectory, severely impacting precision.
- For PLC Control: A slow I/O response will cause a lag in logic execution, thus affecting the production line’s efficiency.
- For EtherCAT Buses: High latency will disrupt the synchronization between devices, impacting overall system performance.
If an industrial PC’s real-time performance is not up to par, the software team will naturally complain, and it could even affect the delivery of the entire project.
How to Test the Real-Time Performance of an Industrial PC?
In a Linux system, which is commonly used in the industrial field, you can use the cyclictest tool to test real-time performance.
Testing Steps:
- Obtain a Test Unit: It is crucial to request a sample from the supplier before purchasing!
- Run the Command: Execute the following command in the Linux terminal:
/usr/bin/cyclictest -p 99 -i 250 -m -a 1 -N - Stability Test: Have an engineer run a 7×24 hour stability test (to simulate an industrial environment) and observe the final
MAXvalue (unit: microseconds, μs).
How to Interpret the Test Results?
- The lower the
MAXvalue, the better the real-time performance. - Ideally, the
MAXvalue should be below 100μs. In more demanding scenarios, it may need to be below 50μs. - If the
MAXvalue exceeds 200μs, the PC may not be able to meet high real-time control requirements. - For example, a result of
MAX: 17142(in nanoseconds) indicates excellent performance.
How to Choose the Right Industrial PC?
Besides real-time testing, consider the following aspects when selecting the right industrial PC:
-
Hardware Architecture:
- ARM/ARM+FPGA: Typically offers low power consumption and high real-time performance.
- x86: Powerful performance but requires optimization for real-time capabilities.
-
Operating System:
- Linux (with RT-Preempt patch): Cost-effective and open-source, suitable for real-time applications.
- VxWorks/Green Hills: Very strong real-time performance, but with higher licensing costs.
-
Supplier Support:
- Does the supplier offer real-time optimization solutions?
- Do they support EtherCAT/Profinet master functions?
Conclusion
When purchasing an industrial PC, real-time performance is a critical indicator that cannot be judged by price and configuration alone. By using a professional tool like cyclictest, you can scientifically evaluate a device’s real-time performance and effectively avoid subsequent compatibility issues.
If you are looking for an industrial PC with excellent real-time performance, especially if you need a Fanless Mini PC, a DIN-RAIL mounting Mini PC, or a Fanless Box PC for applications involving EtherCAT, motion control, or high-precision synchronization, you may want to check out products from Vstrongtech.