3-phase motor control using PLC ladder logic program code
Here's a breakdown of the ladder logic diagram and the corresponding ladder logic program:
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Start/Stop Push Buttons (NO contacts) - These buttons are used to start and stop the motor. The NO contacts are connected to the input terminals of the PLC.
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Start I:1/0 Stop
Motor Thermal Overload Relay (NO contacts) - This is a protection device that detects excessive motor temperature and disconnects the motor circuit. The NO contacts are connected to the input terminals of the PLC.
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Thermal I:1/1 Overload
Relay
Motor Contactor (NO and NC contacts) - The NO contact of the contactor is connected to the coil of the contactor itself to maintain its state. The NO contact of the contactor is connected to the input terminals of the PLC, and the NC contacts are connected to the power supply lines.
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Contactor Coil Q:1/0
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NO NC
Forward/Reverse Push Buttons (NO contacts) - These buttons are used to control the direction of rotation of the motor. The NO contacts are connected to the input terminals of the PLC.
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Forward I:1/2 Reverse
Forward/Reverse Interlock Relays (NO contacts) - These relays ensure that both the forward and reverse directions cannot be activated at the same time. The NO contacts are connected to the input terminals of the PLC.
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Interlock I:1/3 Relay
Motor Overload Indicator (NC contact) - This indicator will be turned on if the thermal overload relay is activated. The NC contact is connected to an output terminal of the PLC.
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Overload O:2/0
Indicator
Motor Forward/Reverse Indicators (NC contacts) - These indicators will be turned on when the motor is rotating in the forward or reverse direction. The NC contacts are connected to output terminals of the PLC.
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Forward O:2/1
Indicator
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Reverse O:2/2
Indicator
