When ( I1) is pressed then the coil ( Q1) is on. In the case of PLC ladder, there will be a push button to provide input. Logic Gate Truth Table for NOT Gate: Input (I1) When the input is high then the output is low and vice-versa. An example of a relay in a simple control application is shown in Figure 7.5. Relays are used to let one power source close a switch for another (often high current) power source, while keeping them isolated. This will allow us to have more options of creating complex logic using essentially the same gates that we have seen so far, albeit with an inverter attached at their outputs. Ladder logic, developed to mimic relay logic, is the main programming method used for PLCs.
We can extend the functionality of the gates we have seen so far by just attaching an inverter to them. In electronics, NOT GATE is also called an ‘ Inverter’ or ‘ Buffer’. An EXNOR logic gate is the opposite of the XOR gate. Let’s see the explanation for each logic gate with PLC implementation, 1. Note: The circuit diagrams are connected to make and break input (I) and output (Q) contact in series and parallel circuits.įor all the circuit diagram, we are representing inputs ( I1) and ( I2) as switches, output ( Q1) as coil/lamp.
WRITE THE LADDER LOGIC PROGRAM NEEDED TO IMPLIMENT EACH OF THE FOLLOWING SOFTWARE
Basically, there are seven types of logic gates as below. Ladder Diagram is a graphical programming language that you use to develop software for programmable logic controllers (PLCs). Each step is then further divided into steps is subsequent paragraphs. 2.2 LADDER LOGIC CONFIGURATION A summary of the steps involved in assigning names to Ladder Logic elements follows. Having unused rungs makes it easy to add needed rungs. Different types of ladder logic diagram that perform different logic gate functions. ladder logic, you will probably need to add more contacts or rungs of logic.