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.

Explain ON delay timer using electrical drawing and PLC program.

Application:-ON delay timer explanation. Explain On delay timer using example and draw electrical diagram and write PLC program for example.

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

Explanation:-

Consider one example for ON delay timer explanation. For example there is a valve in our application and we need to operate it after 20sec when switch S1 is pressed. So as show 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 timer is completed, it will allow supply to pass from its NO contact. Adjust timer time from the dial as per requirement.

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 will start. The set time is 20sec so timer will generate command and it will operate the 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 ON delay timer. In pulse timer ,timer needs pulse of the digital input for operation and in ON delay timer, timer needs digital input for operation.

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).

Combinational logic operation using AND gate and OR gate

Application:-Draw electrical diagram and write PLC program for combinational logic for 3 switches. Use AND gate and OR gate for three switches combinational logic. Operate lamp in the following condition,

If S1 or S2 is ON and S3 is ON, the lamp will be ON.

Components:-Programmable logic controller, Electrical panel, wires, 24VDC switches with NO contacts, 24VDC indication lamp, 24 VDC relay.


Diagram:-Electrical wiring diagram for combinational logic.

Explanation:-

Here we have 3 switches S1, S2, and S3. So the condition is either S1 or S2 should be ON or S3 should be ON. So S1 and S2 should be put in OR gate and this combination should be put in series with S3.

Hence the lamp will be ON if S1 or S 2 is ON and S3 is ON.

PLC program:-

Write the ladder program for combinational logic using ladder diagram language. Here for ladder logic, we can use any PLC system. For PLC logic we need digital inputs and outputs.

For our application, all switches are digital inputs, and the lamp is a digital output. To define digital input address and output address as per below explanation,

Digital inputs:-

S1=I0.0

S2=I0.1

S3=I0.2

Digital Output:-

Lamp=Q0.0

Memory coil:-

Memory bit-M0.0

PLC program Explanation:-

In-network 1 we have considered three digital inputs for three switches S1, S2, and S3. So we have taken NO contact of S1 (I0.0) and S2 (I0.1) in OR gate and. So when S1 or S2 OFF, memory bit (M0.0) will be ON.

Two switches series operation

Application:-Operate lamp if two-panel switches are from different two panels. Draw electrical drawing and write PLC programs using ladder diagram language.

Diagram:-Electrical wiring diagram of two switches series operation.

Explanation:-

For series operation of two switches we can use AND gate logic. Here there are two switches, panel 1 switch, and panel 2 switches. As per AND gate we need to put panel 1 switch NO contact in series with panel 2 switch NO contact as shown in the above electrical diagram.

PLC program:-

Write the ladder program for series operation using ladder diagram language. Here for ladder logic, we can use any PLC system. For PLC logic we need digital inputs and outputs.

For our application, all switches are digital inputs and the lamp is a digital output. To define digital input address and output address as per below explanation,

Digital inputs:-

Panel 1 switch=I0.0

Panel 2 switch=I0.1

Digital Output:-

Lamp=Q0.0

Memory coil:-

M=Memory bit

PLC program Explanation:-

In-network 1 we have considered two digital inputs for two switches panel 1 switch and panel 2 switch. So we have taken NO contact of panel 1 switch (I0.0) in series with panel 2 switch (I0.1) for series operation. So when both are ON, memory bit (M0.0) will be ON.

In-network 2 we have taken NO contact of memory bit (M0.0) to operate a lamp (Q0.0).

Two switches parallel operation

Application:-Make operation in two different control panels so the operator can operate one lamp from two different control rooms. One panel is in the control room 1 and the second panel is in control room 2. The lamp can be operated from two different switches. Explain using and electrical drawing and write PLC program for application.

Components:-Programmable logic controller, Electrical panels, wires, 24VDC switches with NO contacts, 24VDC indication lamp, 24 VDC relay.

Diagram:-Electrical wiring diagram of two switches parallel operation.

Explanation:-

As per our application, we can use the above OR gate for parallel operation. In the application, we are using two switches and one lamp for indication. If panel switch 1 or Panel switch 2 pressed, an indication lamp should be ON. So in the above electrical wiring diagram, we have used panel switch 1 and panel switch 2 in parallel connection so electrical supply can flow either from panel switch 1or Panel switch 2.

PLC program:-

Write the ladder program for parallel operation using ladder diagram language. Here for ladder logic, we can use any PLC system. For PLC logic we need digital inputs and outputs.

For our application, all switches are digital inputs and lamp is a digital output. To define digital input address and output address as per below explanation,

 Digital inputs:-

Panel 1 switch=I0.0

Panel 2 switch=I0.1

Digital Output:-

Lamp=Q0.0

Memory coil:-

Memory bit-M0.0

PLC program Explanation:-

In-network 1 we have considered two digital inputs for two panel 1 switch (I0.0) and panel 2 switch (I0.1). So we have taken NO contact of panel 1 switch (I0.0) in parallel with panel 2 switch (I0.1) for parallel operation. So when panel 1 switch or panel 2 switch ON, memory bit (M0.0) will be ON.

In-network 2 we have taken NO contact of memory bit (M0.0) to operate lamp (Q0.0).

Basic NOR gate operation explanation using electrical wiring diagram and PLC ladder diagram

Application:-In electrical panel there are two switches given for panel ON lamp. Both the switches are optional, the lamp can be OFF either by switch 1 or switch 2.Draw truth table, electrical wiring diagram and write PLC program for this application.

Components:-Programmable logic controller, Electrical panel, wires, 24vDC switches with NO contacts, 24VDC indication lamp, 24 VDC relay.

Diagram:-Electrical wiring diagram and truth table of NOR operation

Explanation:-

As per our application, we can use the above application for the NOR gate explanation. In the application, we are using two switches and one lamp for indication. If switch 1 or switch 2 pressed, an indication lamp should be OFF. So in the above electrical wiring diagram, we have used S1 and S2 in parallel connection so electrical supply can flow either from S1 or S2. We have used NC contact of relay for negative operation, hence the NOR gate.

In the truth table, we can easily understand the conditions of NOR gate,

As per truth table,

If S1=ON OR S2=ON, then R=0

If S1=ON OR S2=OFF, then R=0

If S1=OFF OR S2=ON, then R=0

If S1=OFF OR S2=OFF, then R=1

So the output will be ON only in the last condition.

PLC program:-

Write the ladder program for NOR gate operation using ladder diagram language. Here for ladder logic, we can use any PLC system. For PLC logic we need digital inputs and outputs.

For our application, all switches are digital inputs and the lamp is a digital output. To define digital input address and output address as per below explanation,

Digital inputs:-

S1=I0.0

S2=I0.1

Digital Output:-

Lamp=Q0.0

Memory coil:-

Memory bit-M0.0

PLC program Explanation:-

In-network 1 we have considered two digital inputs for two switches S1 and S2. So we have taken NO contact of S1 (I0.0) in parallel with S2 (I0.1) for NOR operation. So when S1 or S2 OFF, memory bit (M0.0) will be ON.

In-network 2 we have taken NC contact of memory bit (M0.0) to operate panel ON lamp (Q0.0).

Basic NAND gate operation explanation using the electrical wiring diagram and PLC ladder diagram

Application:-Set wiring in the electrical panel so when the operator has to operate two switches to operate one lamp. Make electrical control wiring using a NAND gate. Also, draw the truth table for application and write PLC program using ladder diagram language.

Diagram:-Electrical wiring diagram and truth table of NAND operation

Explanation:-NAND gate operations very important logic in various industrial applications. For example purpose, we have taken two switches S1 and S2 as shown in the above figure. So if the operator wants to ON lamp, he has to OFF both the switches as per the NAND operation. So S1 and S2 must be OFF if we want to ON lamp.

In the truth table, all the conditions have been shown for explanation, it can be easily learned by simple conditional logic,

As per truth table,

If S1=ON AND S2=ON, then R=0

If S1=ON AND S2=OFF, then R=1

If S1=OFF AND S2=ON, then R=1

If S1=OFF AND S2=OFF, then R=1

So the output will be OFF only in the first condition.

PLC program:-Write the ladder program for NAND gate operation using ladder diagram language

Here for ladder logic we can use any PLC system. For PLC logic we need digital inputs and outputs.

For our application, all switches are digital inputs and the lamp is a digital output. To define digital input address and output address as per below explanation,

Digital inputs:-

S1=I0.0

S2=I0.1

Digital Output:-

Lamp=Q0.0

Memory coil:-

M=Memory bit

PLC program Explanation:-

In-network 1 we have considered two digital inputs for two switches S1 and S2. So we have taken NO contact of S1 (I0.0) in series with S2 (I0.1) for NAND operation. So when both are OFF, memory bit (M0.0) will be OFF.

In-network 2 we have taken NC contact of memory bit (M0.0) to operate lamp (Q0.0).