**3. Results and discussion**

A control system is designed and fabricated using microcontroller and CPLD from the point of simplicity and cost effectiveness to act as speed synchronization

#### *DC Motor Synchronization Speed Controller Based on Microcontroller DOI: http://dx.doi.org/10.5772/intechopen.93080*

and direction control for two (or multiple) dc motors, already shown in **Figure 1**. The presented system was tested running the two motors for the long period of time and in different environments. It is observed that the synchronization system was worked to expectation. Some calibration of the analogy to digital conversion (ADC) in the control circuit module was necessary and this was done using software. Calibration had to account for the voltage drop across the resister in series with the control trigger and motor response. The calibration improved the speed range available to the driver circuit of dc motors, confirming the earlier results [1, 7–11]. Once dc motors were running on synchronization mode it was expected that contact noise between the motor brushes and due to the power signals would cause incorrect speeds. Therefore, the error checking software has been included in order to diagnose the erroneous signals, and it is important that this was found not to be a problem. It was noted that there were periodic speed control but unusual cases of erroneous speed behavior. The graphic interface unit has two zones of synchronization, one for when graphic interface unit has its middle value of indications (green-indications), the two motors has same speed, this mode was called synchronization of motors. On the other hand, the second zone of graphic interface has its end value of indications (red-indications), shows that the speeds of two motors were not in same phase. This feature adds realism to the synchronization control system of dc motors by using software.
