an output in a ladder logic program can be controlled by

Of course this piece of ladder logic is only the logic for one motor. AND only has one option and therefore only one line. OR always has two options, and thereby to lines. Because if you follow the lines from left to right at each network, you can see the logic relationships between instructions.

One of the major advantages of ladder logic is that you graphically can build logic. Because for the motor to be activated other the start conditions and not the stop button had to bee true.ĪND logic is implemented with ladder logic as a serial connection of instructions: AND Logic implemented with Ladder Logic as serial connection. But the logic relationship between the start and motor, and the stop button is AND. On the other hand the stop button has to be not pressed for the motor be keep being activated. In ladder logic the OR logic is implemented with a parallel connection of two instructions: OR Logic implemented with Ladder Logic as parallel connection. Either the start button or the motor will set the motor active. The logic relationship between the start button and the motor itself is OR. Because each of these logic relationships can be translated into ladder logic. These logic relationships can with ease be implemented with ladder logic. Between these are the logic relation between them. Each of the buttons and the motor represents conditions for the states of the motor. What is important to notice here is that we have broken down a function description into logic. START OR MOTOR AND NOT STOP Motor (active) We can also add the latching functionality which will be the motors themselves:

Because if these conditions are false the motor will be inactive. Since the motor can only be in two different states we only have to look at the conditions for the motor to be activated. And since the motor can be in two states, we need to look at the conditions for both of these states: We should look at the conditions for the motor. The first conditions for the start and stop buttons for each motor is of course conditions for the motor to start or stop. I did that because with these simple instructions we can quickly implement the logic. You might wonder why I chose the latching over set / reset coils. In this example I will use the latching using the examine if closed (normally open) instruction. The start and stop of the motors can be implemented with the latching or set / reset functions I talked about earlier in this tutorial. Each motor has a start and a stop button to start and stop the motor.

Let’s take a look at a simple example of interlocking with two motors, where only one can run at a time.

An output in a ladder logic program can be controlled by