Motor Control Ladder Logic

Electric circuit for the motor starter control.

Motor control ladder logic. There are lots of motors and conveyors used in industries for different purposes. Start pushbutton is pressed. This is plc program for forward and reverse control for 3 phase asynchronous motor. The motor control training system builds both knowledge and skills across topics like manual motor control control ladder logic motor starters and automatic input devices.

Assume we have a motor that could be started and stopped from 3 different places. To keep the motor running even after the operator removed its control switch s we could change the circuit in several different ways. More advanced section for motor section is available later on in the training section. Ladder program for the motor starter control.

The ladder program is shown in figure a is designed for the following sequential task. Plc motor control scheme initially i0 1 status bit is a logic 1 because the normally closed nc stop pushbutton is closed. The purpose of this section is to give plc programmers a sense of some of the basics in motor control in ladder logic. Reference input sp0 i 1 0 is closed the output coil c0 o 3 0.

Ladder logic program for motor control is explained below. Ladder logic is widely used to program plcs where sequential control of a process or manufacturing operation is required ladder logic is useful for simple but critical control systems or for reworking old hardwired relay circuits. In some cases motors or conveyors need forward and reverse operation for some control purpose. Motor contactor or starter coils are typically designated by the letter m in ladder logic diagrams.

3 phase motor control using plc. Ladder diagram of star delta starter with a mitsubishi plc. This innovative approach to bringing motor control training to wherever you need is one example of why amatrol is the world s leader in skills based interactive technical learning. Plc motor control ladder logic.

As programmable logic controllers became more sophisticated it has also been used in very complex automation systems. These inputs are used to control normally open contacts in a line of ladder logic programmed into the plc. We have included some of the most used controls. Another great example of how to use a plc for star delta start of an ac motor is example 5 in the pdf file below.

The ladder logic for a star delta motor control is quite simple and that is one of the advantages of using a plc for motor control. Plc has to start a motor when the start button is pressed and interlocks must be in healthy condition.