A main control device includes a
processing module, a first dial, a second dial, a reverse module, a first switch, and a second switch. The
processing module has a switching pin and a plurality of
signal pins. The first dial has a plurality of first
signal switches respectively connected to the plurality of
signal pins. The second dial has a plurality of second signal switches respectively connected to the plurality of signal pins. One end of the reverse module is connected to the
processing module. The first end of the first switch is connected to the plurality of first signal switches, the second end of the first switch is connected to one end of the reverse module and the switching pin, and the third end of the first switch is connected to an
operating voltage source. The first end of the second switch is connected to the plurality of second signal switches, the second end of the second switch is connected to the other end of the reverse module, and the third end of the second switch is connected to the
operating voltage source.