Oscilloscope control design based on labview

We know that the current digital oscilloscope can accurately capture various periodic signals and non-periodic signals. The digital oscilloscope has become one of the most important equipment for collecting, recording and analyzing various signals in scientific research experiments and engineering projects . In many cases, it is necessary to process and analyze the data collected by the digital oscilloscope, and finally complete the needs of remote automatic testing and analysis. Therefore, remote automatic control of the oscilloscope, automatic operation of the various functions of the oscilloscope and data processing have become a necessary link in many scientific research experiments and engineering projects. Recently, I often receive calls from many engineers asking about how to control the oscilloscope. Let's talk about the steps and methods of computer control of oscilloscopes, and use examples for analysis and explanation.

1. System hardware architecture

Figure 1 System hardware architecture

The computer controls the oscilloscope by establishing a connection with the oscilloscope via GPIB or LAN (network port). The hardware architecture diagram of the system is shown in Figure 1.

2. System software architecture

Figure 2 System software architecture diagram

Figure 2 is a diagram of the system software architecture of the computer-controlled oscilloscope. The entire software development and the operating environment after the software development are on the Windows operating system platform. The application program written controls the oscilloscope through TekVISA.

3. Example of computer controlled oscilloscope steps (taking LAN port control as an example, development software: labview)

The following is a detailed description of the steps on how to program a computer to control an oscilloscope.

3.1 Selection of development software

There are many popular analysis and development software on the market, including VC/VC++, VB/VBA, Matlab, Labview, LabWindow CVI and other development software. You can choose according to your personal preferences and familiarity with a certain software.

3.2 Installing the Driver

TekVISA is a VISA library developed by TektroNIx. It can be downloaded for free on the Tektronix website. If it is an oscilloscope from another company, you can also use TekVISA software. After TekVISA is running, it will automatically search for LAN and GPIB interface devices connected to the network and display them in the prompt box, as shown in Figure 3. Different instruments can be distinguished based on different IP addresses.

Figure 3 TekVISA automatically searches for instruments

3.3 Selection of control interface

There are many interfaces to establish connections between computers and oscilloscopes, mainly GPIB, LAN, USB and other interfaces.

a..LAN [TCPIP::192.168.0.188::INSTR]

b. GPIB [GPIB0::1::INSTR]

c. USB [USB::0X1234::125::A22-5::INSTR](DPO4K/3K/AFG3K)

3.4. Basic settings of oscilloscope and PC (taking LAN port as an example)

a. Set the IP address of the oscilloscope, for example: 192.168.0.168

b. Set the IP address of the PC, for example: 192.168.0.188

c. Turn off the firewall of the oscilloscope and PC's Windows and anti-virus software

3.5 Start TekVISA and make related settings

a. Change the oscilloscope's communication interface to LAN, as shown in Figure 4 below.

Figure 4 The oscilloscope's communication interface is changed to LAN

b. Open TekVISA Instrument Manager on the PC, see Figure 5 and Figure 6, and check whether the PC and oscilloscope are connected and whether the oscilloscope is found.

3.6 Start LABVIEW and start writing control program

a. Start LabVIEW and open the Front Panel of LabVIEW to write the relevant software operation interface, as shown in Figure 7.

Figure 7 LabVIEW control oscilloscope software operation interface

b. Open the Block Diagram programming interface of labview to write the program to control the oscilloscope.

c. Create an object, see Figure 8.

Figure 8

d. Set the oscilloscope parameters. According to the actual measurement requirements and the requirements of subsequent data processing, set the oscilloscope acquisition mode, oscilloscope channel, vertical resolution, sampling rate, trigger type, record length and other parameters, as well as the corresponding measurement parameters. Figure 9 shows how to set the oscilloscope to automatically measure the frequency, and Figure 10 shows how to automatically read the oscilloscope's measurement value.

e. After the oscilloscope meets the trigger condition, it collects data and displays the collected data on the software interface. See Figure 11 and Figure 12.

In this way, a complete LabVIEW program for controlling the oscilloscope is written, and engineers can also add the data processing part according to their own application requirements.