Remote laboratories based on data acquisition cards offer a more versatile solution, as a great part of the lab equipment’s can be replaced by a single DAQ card.

For remote laboratories involving exercises with analog circuits, for example, we are likely to have virtual instruments programmed to perform the tasks of a function generator and oscilloscope. These instruments are created by using virtual instrumentation and are programmed to use the resources of a DAQ card to generate analog waveforms and to read analog signals. User interfaces can be created to look similar to real devices and therefore can add the atmosphere and feeling of a real environment.

In order to create a remote laboratory with a DAQ card it is necessary to previously consider the types of exercises to be performed, so that the proper DAQ device can be chosen. Experiments can vary on the required signal frequencies and this must be taken into account if we want the circuit behavior to be well visualized.

In the field of electronics, one example of a remote laboratory implemented using a data acquisition card is provided by the Carinthia University of Applied Sciences. This is a hybrid online lab and consists of a programmable analog ASIC device (ispPAC 10) that implements a variety of common analog functions. The circuit can be programmed and tested remotely.

Figure 6 shows the PCB (Print Circuit board) assembled for this remote lab. The DAQ hardware used with this lab was the PCI-6251 from National Instruments is a high-speed multifunction data acquisition (DAQ) board (for more details regarding technical characteristics of this board visit). This device has 16 analog inputs and 2 analog outputs. The data acquisition terminals were connected to the proper inputs and outputs of the ASIC in order that the signal on each I/O terminal could be acquired and displayed to the user. The server that controls the hardware of the ASIC remote laboratory runs LabVIEW and it’s built in Web server, which publishes the virtual instruments.

The DAQ hardware for this lab was programmed to acquire a finite number of samples and the sampling rate is adjusted according to the time interval specified by the user. Remote Laboratories based on Embedded Web Servers

Today, very compact Embedded Web servers (Micro Web servers, MWS) can be used in a wide range of applications. It can replace personal computers required in remote labs with special hard- and software. They can be used in educational and also in industrial environments. MWS are cheap, and almost every measuring instrument has a serial port (which is used for the connection to the MWS). Up to seven instruments can be connected to one MWS at the same time. Measurement results can also be transferred to computers running software like MatLab, Simulink etc., to carry out further numerical and graphical analysis.

Figure 9 shows a typical configuration of hardware control using Micro Web server technology.

 

 

Micro Web servers make the executions of different user interfaces (UI) possible, html pages or flash animations are especially suited. This equipment allows getting a feeling that users are controlling a real instrument panel by using e.g. a touch screen (Figure 10).