Valve operation inside the machine for cleaning the material

Application:-Consider there is one machine in which one water Valve used for cleaning the job. Valve should be operate on following condition,

-machine door should be closed

-Vale should be on after 10 second if door is closed and start switch is pressed.

Components:-Programmable logic controller, Electrical panel, wires, 24V DC switch with NO contacts, 24VDC solenoid valve, and 24 VDC timer, door close Limit switch.

Diagram:-Electrical wiring diagram for the above application.

Explanation:-

Here we need to use door close switch feedback for valve. As per the condition door close feedback is required for timer. So we need to put NO contact of limit switch in series with Start switch. So when switch and limit switch feed backs are ok, timer will be ON and after 10 seconds valve will be ON.

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 switch S1=I0.0

Door close =I0.1

Digital Output:-

Valve=Q0.0

PLC program Explanation:-

In network 1 we have taken ON delay timer. Timer can be ON by using NO contact of start switch S1 (I0.0) and door close feedback (I0.1). On delay can be set at PT (10s) so after 10 seconds valve (Q0.0) will be ON.

Here PT is preset time at which we can set time and ET is elapsed time at which we can monitor time.