Data acquisition card has been designed as a card connected to the industrial standard architecture (ISA) slot in the motherboard of a Pentium III personal computer in order to control the speed of a DC motor in real time. A program in C++ language has been written to realize and implement an algorithm of the controller and to get in and out of the signals to and from the designed card. The two sampled signals, the speed of the DC motor and the current in the armature, are processed by using digital proportional plus integral (PI) control and the output signal is the actuating signal for a thyristor bridge to control the speed of DC motor. The transient response for current and speed are drawn in PC monitor in the real time with different colors using graphics.

Keywords: Data acquisition, card (DAQ), ISA, speed control, DC motor, PI controller.