Realizing Remote Data Acquisition Based on C/S Structure in LabVIEW

LabVIEW has powerful remote data acquisition capabilities, and there are four main implementation methods: Method 1, software operation interface sharing method, using RemotePanels technology to achieve remote data acquisition; Method 2, DAQ device sharing method, using RDA technology to achieve remote control of DAQ devices; Method 3, data publishing method, using TCP technology to achieve remote data acquisition; Method 4, data sharing method, using DataSocket technology to achieve remote data acquisition [. Regardless of which method is used, the system consists of a client (Client) and a server (Server) connected through a network, in which the DAQ device is installed on the server, and the client controls the DAQ device on the server through the network to complete data acquisition. The system composition is shown in Figure 1.

Remote Data Collection Using Remote Panels Technology

Starting from LabVIEW 6.1, LabVIEW has integrated RemotePanels technology, allowing users to directly open and operate the front panel of the VI located on the server computer on the client computer. You can even embed the front panel window of the LabVIEW VI into a web page and operate it directly on the web page. This is a way to share the software operation interface. Write the server software in the usual way to control the DAQ device to complete data acquisition. Through certain settings, publish the front panel of the server software to the client. In this way, users can directly operate the software located on the server on the client to achieve remote data acquisition. It only takes two steps to set up and use Remote Panels in LabVIEW:

The first step is to start the LabV IEW Web Server service on the computer at the LabV IEW Web Server end: Before using Remote Panels on the client, you must first run LabV IEW on the server computer and use the LabV IEW Options configuration dialog box to configure the Web Server's file path and network parameters, client access rights, and VIs access rights. In order to provide web browser access, you must use the Web Publish Tool to publish the web page when configuring the server.

The second step is to connect and run Remote Panels on the client computer. There are two ways to operate Remote Panels: Method 1: Use the Connect to Remote Panels tool in the LabVIEW environment to directly operate Remote Panels. Method 2: Use a web browser to directly operate Remote Panels on a web page. If you enter the server URL in the address bar of the client's web browser, you can directly operate Remote Panels on the web page. In a local area network, the URL format is: http://PcName:Port/ViName.htm; on the Internet, the URL format is: http://IpAddr:Port/ViName.htm. When Remote Panels appears on the browser, you can get control of Remote Panels through the right-click drop-down menu. Using a web browser to operate Remote Panels does not require the installation of LabVIEW, but only requires the installation of a LabVIEW Run-Time Engine. Figure 2 shows a virtual instrument front panel located on a server opened in an IE browser.

LabVIEW's Remote Panels can not only be viewed, but also controlled in the LabVIEW environment or on a browser. This powerful function allows developers to easily create remote applications, allowing users to easily monitor various situations in the office, laboratory, or even production line while sitting in front of their home computers on weekends. The disadvantage of this method is that the test data cannot be obtained on the client side.

Realizing Remote Data Collection Using RDA Technology

Use RDA (Remote Device Access) technology to share devices on the server, and program on the client to directly control the DAQ device on the server to achieve remote data acquisition. RDA programming is exactly the same as using a local DAQ device. The steps to use RDA technology to achieve remote data acquisition in LabVIEW are as follows:

The first step is to configure the RDA server. The RDA server needs to install NI-DAQ6.0 (or higher) and DAQ devices, set the server's IP address, for example 192.168.0.1, and its subnet mask is 255.255.255.0. Then start the RemoteDevice Access Server on the server. If necessary, you can set the RDA access password in the properties dialog box of the DAQ device.

The second step is to set up the client. The RDA client should install the same version of NI-DAQ as the server, otherwise the DAQ device will not be able to connect. Set the client's IP address, for example 192.168.0.2, and its subnet mask is 255.255.255.0. The RDA client is more complicated to set up, and is usually done in the following steps:

In the client's MAX (Measurement & Automation Explorer) directory tree on the left, right-click the Devices and Interfaces item and select "Create New..." in the pop-up menu. In the Create New window, select RDA/Ethernet Device.