## How does a PLC control a motor?

A PLC has to start a Motor when the Start button is pressed. It has three interlocks which are Motor Vibration High, Overload & Motor Temperature High. if any of the interlock activated then PLC has to stop the motor immediately. PLC has to stop the motor if the stop button is pressed.

How does PLC control motor speed?

The PLC has to give set point for VFD drive to control the motor speed, this can achieved either automatically from the PLC or by the operator action from the HMI. According to set point value, PLC will control the drive speed and VFD drive finally controls the motor speed.

### How is ladder logic used in PLC?

Ladder diagram, better known as ladder logic, is a programming language used to program PLCs (programmable logic controllers). Contacts are placed in series to represent AND logic and in parallel when using OR logic. As with real relays, there are normally open contacts and normally closed contacts.

Ladder logic is used to develop software for programmable logic controllers (PLCs) used in industrial control applications. The name is based on the observation that programs in this language resemble ladders, with two vertical rails and a series of horizontal rungs between them.

#### How to control variable frequency drive with plc?

This is a complete tutorial about PLC ladder logic to control variable frequency drive (VFD) for motor speed control with speed selection from Field Local Panel or SCADA graphics. How to Control VFD with PLC ? Commissioning is needed for the proper function of VFD.

How to unlatch a circuit using PLC ladder logic?

(Push button only provides momentary contact and we need to latch the action so motor forward coil contact will be used) Put NC contact of motor reverse output (Q0.1) in series for unlatching the circuit because both forward and reverse should not run at the same time.

## How to control VFD with PLC using ladder logic?

In this Network 1, we are checking whether the VFD is ready to start. This signal will come when all the conditions are healthy as well as safety and power feedbacks are active. In the Network 2, When start button is pressed, VFD Drive_DO bit will be set, if Ready_to_Start and No Error will be there.

When to use plc to control a motor?

In some cases motors or conveyors need forward and reverse operation for some control purpose. For example overhead crane, in crane every time operators moves it forward and reverse for material handling. So we can use PLC systems for programming the motor for forward/reverse operation.

How does a PLC control a motor? A PLC has to start a Motor when the Start button is pressed. It has three interlocks which are Motor Vibration High, Overload & Motor Temperature High. if any of the interlock activated then PLC has to stop the motor immediately. PLC has to stop the motor if…