If you are using Control Logix plc, we will make a flip-flop example with AOI. I will show you how to easily make a flip-flop block with add-on instructions.
Normally, you can use one Timer On and one timer-off instruction for the flip-flop circuit. But creating a new one for each flip-flop circuit would be a waste of time. Instead, I previously explained how to create AOI in our previous articles.
We can create once with the Add-On-Instruction and use the command that we have created wherever we want.
PLC Add-On Instruction Create
Now we will create the flip-flop command using AOI.
By doing a little more here, we will also identify some limitations. As you know in control logic plcs, times are calculated in milliseconds and all input inputs are also in milliseconds.
Therefore, in the flip-flop example, we will do here, we will ensure that the user cannot enter a value below at least 20 milliseconds.
For example, if you enter 19 milliseconds into the flip-flop block, it will automatically set to 20 milliseconds.
We will use GEQ and LES commands for this.
If the entered value is less than 20 milliseconds;
With the MOV command, we will assign 20 to the Timer ON (TON) preset value.
In the same way, we will assign 20 to the Timer OFF (TOF) preset value.
PLC Flip Flop Block
Flip Flip block as you know,
It is in the form of blinking for a certain period of time, and we need 2 Timer commands to do this in the easiest way.
We will use 1 Timer ON (TON) command and 1 Timer OFF (TOF) command.
It will give an output until the millisecond entered in the timer ON value,
The output will not give an output for the millisecond time entered in the Timer OFF value.
I can send the AOI file for you, you can also import it easily and use it if you want.
And you see the PLC Flip-Flop AOI parameter below.