Development of interface card for virtual instruments by using PLD

A typical instrument is a device that used independently. It includes its own power supply, controllable buttons, displaying front panel and inside signal processor. Within automatic testing system, the instruments act as either listener or talker. All of the testing procedures controlled by personal computer, and all of the measurements appear on PC’s screen. Therefore virtual instrument’s technology is the choice of engineers who want a cost-effective solution to their processing needs. A programmable logic device (PLD) is a general name for a digital integrated circuit capable of being programmed to provide a variety of different logic functions. Thus a single PLD can replace a number of SSI and MSI integrated circuits that lead to lower cost designs. When a digital system designed using a PLD, changes in the design can easily make by changing the programming of the PLD without having to change the wiring in the system. In this project a PC-based instrumentation system is present. The function of the card is measurement and control circuitry for a DC voltmeter. To increase the performance, all of the interface digital circuits will be integrated with the technique of PLD.