How do I choose the right computer for my data acquisition system?

Computer is one of the most critical parts of data acquisition system. After choosing DAQ equipment, you should start to choose the right computer. How to choose a computer with suitable processing power and compatibility is a science. Today, I will give you a "special lesson" and share the five major factors of computer selection summarized by NI test masters.

Almost every computer has three main components that affect the computing's data management capabilities: the processor, RAM, and hard drive . The processor is the part of the computer that is responsible for parsing and executing instructions, just like the brain. The processors in most modern computers are dual-core or quad-core, which means that the computer can use two or more independent processors (called "cores") to read and execute program instructions.

Computer processing power also includes RAM, hard drive size, and processor speed. With more RAM, you can increase speed and run more applications at the same time. With more hard drive space, you can store more data. Finally, a faster processor means faster application speeds. Generally speaking, faster is better, but processor speeds may vary from one brand to another. If you need to analyze or save data collected from your application, computer processing power is a key feature you need to consider.

Portability is an essential feature if you frequently move between applications or locations . For example, if you need to take measurements in the field and return to the lab to analyze the data, a portable computer is essential.

In addition, portability is also very important if you need to monitor applications in different locations. When evaluating portability, there are two factors to consider: product size and weight (it should be noted that the lighter the computer, the lower the performance may be.)

If you need a powerful computer but need to collect data remotely, you can consider building a distributed DAQ system. This allows you to place your computer in a control room or laboratory, while ensuring the safety of your computer and extending your measurement system to the field via Ethernet.

If your application is monitored in extreme environments, ruggedness is critical. The operating environment (for example, operating and storage temperature, relative humidity, and maximum altitude) determines the ruggedness requirements for the computer.

Standard commercial off-the-shelf computers are not designed to withstand harsh industrial environmental conditions . Typical specifications are 50 °F to 95 °F (operating temperature), -13 °F to 113 °F (storage temperature), 10,000 feet (operating altitude), and 15,000 feet (storage altitude); computers that exceed these specifications are considered rugged computers. When designing a system, consider the environment in which the system will operate. If severe vibration or temperature fluctuations could result in the loss of critical data, then it is recommended that you choose a rugged or industrial computer.

The modularity of your computer is also an important factor to consider if you are considering future application requirements or need to handle multiple applications. Modularity determines the extent to which you can separate and reorganize the components of the system. You can modify and adapt the system to meet current needs and allow for future expansion requirements; you can also upgrade individual components without purchasing a completely new system.

For example, with a modular tower computer that has a PCIe slot, you can install a new hard drive if you need more space or a DAQ device with a faster analog-to-digital converter if you need faster sampling. Laptops and tablets offer portability, but they are more integrated and therefore more difficult to upgrade. Modularity can be an important feature if you need to adapt your current application to future needs.

The operating system is an important feature to consider when selecting a DAQ computer. By far the most common general-purpose operating system is Windows, but DAQ and control applications may require a more specialized operating system.

An RTOS can run deterministically, allowing applications to execute with precise timing requirements. An RTOS is a deterministic system because it is not responsible for deciding which process occurs when; however, you can define the order and timing of processes, giving you greater control over your application, and execution will be much faster than with a nondeterministic operating system. This is especially important in control applications where critical tasks need to be prioritized.

Based on the previous five questions, the following table compares the most common computer types.