| 摘要 |
The electric motor control circuit has two inverting relays (P1,P2) to connect the terminals of the motor to the electric supply. The relays switch the polarity delivered to the motor. The control signals (cmd1,cmd2) driving the relays are obtained from a sequential circuit that takes into account the current connection in determining the next connection. The microcontroller (COP) delivers a signal representing the state of each of the two relays. This signal is passed to logic circuits (2,3) that generate the relay drive signals. The current state of the relays is also an input into the logic circuits. If the microcontroller delivers incorrect signals the logic circuit inhibits any change but the correct one.
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