Technical Advantages of Virtual Oscilloscopes

Virtual instruments are user-defined, whereas traditional instruments are fixed and vendor-defined.

Traditional instruments and software-based virtual instruments have many of the same structural components, but are completely different in architectural principles

Every virtual instrument system consists of two parts-software and hardware. For the measurement task at hand, the price of a virtual instrument system is comparable to, if not many times less than, a conventional instrument with similar functionality. And, because virtual instruments offer greater flexibility when measurement tasks need to be changed, the savings accrue over time.

Without using vendor-defined, pre-packaged software and hardware, engineers and scientists gain maximum user-defined flexibility. Traditional instruments package all software and measurement circuitry together to provide the user with a limited set of capabilities using the instrument front panel. Virtual instrument systems, on the other hand, provide all the software and hardware devices needed to accomplish a measurement or control task, and the functionality is fully customizable by the user. In addition, with Virtual Instrument Counting, engineers and scientists can customize acquisition, analysis, storage, ****enjoyment and display functions using efficient and powerful software.

Here are some examples of the flexibility of virtual instruments:

⒈ an application, a different device

In this example, an engineer is using the NI Lab ⅥEW and the M series DAQ devices on the lab's desktop computer PCI bus to develop an application to create a direct current (DC) voltage and temperature measurement application. After completing the system build, he needs to configure the application on a production tier PⅪ system to complete testing of the new product. Or, he may need the application to be portable, so he chooses the NI USB DAQ product to accomplish the task. In this example, whatever the choice, in all three cases he can use the virtual instrument only in the same program without changing the code.

Peake many applications, one device

Suppose there's another engineer who has just completed a project to measure motor position using the latest M-Series DAQ devices and integral encoders. His next project is to monitor and record the power of this motor. He can reuse the same M-Series DAQ device even if the task is completely different. All he needs to do is develop a new application using the virtual instrument software. In addition, the project can be combined with a single application or run on a single M-Series DAQ device if desired. NI is committed to using commercially available technologies from companies such as Microsoft, Intel, Analog Devices, Xilinx, and others: NI utilizes many of Microsoft's technologies in operating systems (OS) and development tools; on the hardware side, NI builds on Analog Devices' research in A/D converters. research.

Basically, virtual instrumentation systems are software-based, so if something can be digitized, it can be measured. Therefore, the measurement hardware can be evaluated in through two axes, namely resolution (bits) and frequency. Referring to the graph below, you can see how the measurement performance of virtual instrument hardware compares to that of traditional instruments.NI's goal is to extend the curve in frequency and resolution and to push the envelope within the curve. Many engineers and scientists use a combination of virtual and traditional instruments in their labs. In addition, some traditional instruments provide specific measurements that engineers and scientists would rather have defined by the vendor than by themselves. This begs the question, "Can virtual and traditional instruments be compatible?"

Virtual instruments are fully compatible with traditional instruments, without exception. Virtual instrument software often provides libraries of functions that interface with common common instrument buses such as GPIB, serial buses, and Ethernet.

In addition to providing libraries, more than 200 instrument vendors provide more than 4,000 instrument drivers for the NI Instrument Driver Library. Instrument drivers provide a high-level and readable set of functions and instrument interfaces. Each instrument driver is designed for a particular model of the instrument, thus providing an interface to its unique capabilities. A fundamental trend in the automated test industry is the significant shift toward software-based test systems. For example, the U.S. Department of Defense (DoD) is one of the largest automated test equipment (ATE) customers in the world. In an effort to reduce test system costs and increase reuse, the DoD, through the Navy's NxTest program, has determined that future ATEs will use an architecture based on modular hardware and reconfigurable software, called integrated instrumentation. The adoption of integrated instrumentation represents a significant development in the standards and specifications for future military ATE systems and reflects a fundamental shift toward reconfigurable software being at the core of future systems. Successful application of software-based test systems, such as integrated instrumentation, requires an understanding of the hardware platforms and software tools available on the market, as well as an understanding of the differences between system-level architecture and instrument-level architecture.

The Comprehensive Instrumentation Executive Group defines comprehensive instrumentation as "a reconfigurable system that connects a range of basic hardware and software components through standardized interfaces to generate signals or make measurements using numerical processing techniques." This has many of the same properties as virtual instrumentation, which is "a software-defined system in which the functionality of general-purpose measurement hardware is defined by software based on user needs". Both definitions enjoy the *** same nature as instruments with customizable functionality running on top of commercially available hardware. By shifting measurement functionality to user-accessible and reconfigurable hardware, instruments that utilize this architecture benefit from systems with greater flexibility and reconfigurable functionality, which in turn improves performance and reduces cost.