Sequential operation of two lamps.

Sequential operation of two lamps.

Application:-Operate two lamps in sequence. There are two lamps in the system and we need to operate it in sequence, hence first L1 will be on and after 10s second L2 will be ON.

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

Explanation:-

As per above application, there are two lamps in the system and we need to operate them in sequence. So when lamp on/off button is pressed L1 will be on and second lamp L2 will on after 10 second delay. In this case we need to use on delay timer because we are giving delay between two lamps.

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 on/off switch is digital input and lamps are the digital output. So define digital input address and output address as per below explanation,

Digital inputs:-

Digital Output:-

L1=Q0.0

L2=Q0.1

Memory Coil:-

On/off switch:-M0.0

PLC program Explanation:-

In network 1, we have used NO contact of lamp ON/OFF (M0.0), so when switch is pressed L1 (Q0.0) will be on immediately.

In network 2, we have used NO contact of L1 (Q0.0) to operate L2 (Q0.1). Here we used on delay timer to provide delay between two lamps.

Explain OFF delay timer using example

Application:-Explain OFF delay timer using example. Also draw electrical diagram and PLC program for example

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

Diagram:-

Explanation:-

Consider one example for OFF delay timer explanation. For example there is a valve in our application and we need to close it after 20sec when switch S1 is pressed. So as shown in above circuit supply will pass from No contact of the switch and will go to timer supply. When switch is pressed timer will start first and operate valve and meanwhile off delay will start so after time valve will be close automatically.

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 switch S1 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

Digital Output:-

Valve=Q0.0

PLC program Explanation:-

In network 1 we have taken NO contact of Start switch S1 (I0.0) so when switch is pressed, timer and valve (Q0.0) will start. The set time is 20sec so timer will generate OFF command to stop valve (Q0.0).

Here PT is preset time at which we can set time and ET is elapsed time at which we can monitor time. Do not mix up the pulse timer and OFF delay timer. In pulse timer, timer needs pulse of the digital input for operation and in OFF delay timer, timer needs digital input for operation.

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.