Explain Leak testing System using example.

Application:-Make a leak test system. Write PLC program for leak test system using ladder diagram language.

Diagram:-

Explanation:-

As per the above application, there is one pipe in the system. We need to check its leakage by applying pressure up to 4- 5 bar. For leakage testing, the first pipe will be put into the fixture and one side pipe will be blocked completely. From the other side, the pressure will be applied.

The transmitter will read the pressure. Once the pressure achieved into the pipe, the system will close the inlet pressure valve and hold pressure into the pipe. If there is no pressure drop for 1 minute, the pipe is ok and if the pressure drop measured during 1 minute, the pipe is leaked.

PLC program:-

Write the ladder program for the 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.

Digital inputs:-

Start Button=I0.0

Digital Output:-

Inlet Valve=Q0.0

Ok lamp=Q0.1

M Memory:-

MD24= Set Pressure

MD20=Actual Pressure

Network 1:-Inlet valve for air supply

 

Network 2:-Inlet valve reset when pressure achieved

Network 3:-Indication timer for ok pipe

PLC program Explanation:-

In network 1, the inlet valve (Q0.0) will on when the start button (I0.0) is pressed. Here we used set coil so the output will be set after the start button pressed.

In network 2, the inlet valve will be off when Actual pressure (MD20) is greater or equal to set pressure (MD24).

In network 3, if the pressure will not drop from the pipe for 60 seconds, ok indication lamp will be on.

Explain increment instruction in the PLC using example.

Explain increment instruction in the PLC using an example.

Application:-Understand the concept of increment instruction in the PLC. Write the PLC program using a ladder diagram language to understand the concept.

Diagram:-

Explanation:-

The increment instruction is used to add value.it will add 1 in input/output value. Generally, this instruction is used to increment the value of the application. For example, if you want to count value periodically. Example purpose we have taken here HMI so the user can enter value and instruction will increment the value.

So for that, we can take the input/output register for example. Here MW 20 is the input/output register.

PLC program:-

Write the ladder program for NEG instruction using ladder diagram language. Here for ladder logic, we can use any supported PLC system like S7-1200, S7-1500, or any other PLC which can support this instruction. In our application, we have used S7-1200 PLC for reference.

M Memory:-

Input/output value:-MW20

Network 1:- INC instruction operation

 

PLC program Explanation:-

In network 1, we have taken increment instruction. So 1 value will be added into MW 20 register. Hence IN/OUT+1=IN/OUT 

Explain MAX instruction using example.

 Explain MAX instruction using example.

Application: -Understand the concept of MAX instruction in the PLC. Write the PLC program using ladder diagram language to understand the concept.

Diagram: -

Explanation:-

Here we will understand the concept using an example. MAX instruction is used to define MAX value out of two values. So this instruction will compare two value and update the result in the output register.

For example assume we want to show MAX value out of two values. So we can take two values entry (MW10 and MW12 register for two value entry) in the HMI and one output field for output (the result will be updated in the MW14 register). In this entry field, we will enter two values here 50 and 60 so the output result will be 60.

PLC program:-

Write the ladder program for MIN instruction using ladder diagram language. Here for ladder logic, we can use any supported PLC system like S7-1200, S7-1500, or any other PLC which can support this instruction. In our application, we have used S7-1200 PLC for reference.

M Memory:-

IN 1:-MW40

IN 2:-MW42

OUT:-MW44

Network 1:- MAX instruction operation

 

PLC program Explanation:-

In network 1, we have taken MAX instruction. Here we are entering 50 in the MW 50 and 60 in the MW42 so the result will be updated in the MW 44 register. And it will be 60