Explain basic pulse timer of PLC using example

Application:-Explain pulse timer using example. Operate solenoid after 10 second in the control panel when start button pressed. Solenoid should be ON after 10 seconds. Draw electrical circuit and write PLC program using ladder diagram language.

Components:-Programmable logic controller, Electrical panel, wires, 24vDC switches with NO contacts, 24VDC solenoid valve, and 24 VDC timer.

Diagram:-Electrical wiring diagram of solenoid operation with pulse timer.

Explanation:-

Generate pulse timer can be used for many application. It can be used to set output for some duration.

The instruction is started when the result at IN changes from 0 to 1.Positive edge of the input can be used in this timer. Once positive edge of the signal is detected timer will start and it will remain ON till its time completed.

Here in above application we will use pulse timer. We want to ON solenoid after 10 seconds and we have one push button. So when operator press start button, after 10 second solenoid should be ON. In above application when start button is pressed timer will start and after 10 second timer’s NO contact will start the solenoid.

PLC program:-

Write the ladder program for above application using ladder diagram language. Here for ladder logic we can use any supported PLC system like S7-1200, S7-300, S7-1500 or any other PLC which can support this instruction. For PLC logic we need digital inputs and outputs.

For our application start pushbutton is digital input and valve is the digital output. So define digital input address and output address as per below explanation,

Digital inputs:-

Start PB=I0.0

Digital Output:-

Valve=Q0.0

PLC program Explanation:-

In network 1 we have taken NO contact of Start push button (I0.0) so when push button pressed, timer will get positive edge of start pushbutton and start to count time. Once 10s is completed, valve (Q0.0) will be ON.

Here user can set required time at PT and can watch time at ET (Elapsed time).