June 28, 2020

Automatic overhead tank system.

Automatic overhead tank system.

Application:-Make automatic system for overhead tank in the house. Provide PLC based automatic system so it can control motor as per water requirement. 




Explanation:-

Generally in home we are using overhead tank for water supply in the house. But mostly we are using manual system to fill the tank, in this system we need to check tank level physically and start/stop the motor. So by this application we will make automatic system so it can fill tank as per the level of the tank.

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/stop switch and buttons are digital inputs and pump is the digital output. So define digital input address and output address as per below explanation,

 

Digital inputs:-

Start=I0.0

Stop=I0.1

Trip=I0.2

High Level=I0.3

Low level=I0.4

Digital Output:-

Pump=Q0.0




PLC program Explanation:-

In network 1, we have written start/stop logic in this network. When start button is pressed, memory coil will be latched. We have used latching circuit for this so circuit will be latched automatically.

In network 2, in this network we have used pump operation so when low level is detected then pump will be on and if high level detected then pump will be off automatically.

If cycle stop button is pressed during operation, cycle will be off.

If motor trip during the operation, cycle will be off.



Level indications in the HMI for the water tank.

Level indications in the HMI for the water tank.

Application: - There is one level tank in the system and we need to show levels of tanks in the display. Write the PLC program using ladder diagram language. 



Explanation:-

In above application we will not consider all system. We need to add additional feature in the existing system. System already running but we want to add level sensor indication in the display so operator can see level of the tank easily. And he can manage system by observing level in the display.

 

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 high level and low level are digital inputs.

Digital inputs:-

Low level=I0.0

High level=I0.1

 

M memory:-

Low level indication=M0.0

High level indication=M0.1




PLC program Explanation:-

In network 1, we have taken NO contact of low level sensor (I0.0) and operate M coil (M0.0) for low level indication in the display.

In network 2, we have taken NO contact of high level sensor and operate M coil (M0.1) for high level indication in the display

NO contact and NC contact is depended on the sensor type. If you have NPN type sensor then we can use NC contact also.


















June 21, 2020

Count boxes on the conveyor

Application:-There is one conveyor in the factory and boxes are moving on the conveyor. Write PLC program to count boxes moving on the table.

 Components:-Programmable logic controller, electric DC motor, sensor, wires.



Explanation:-

There is one system in the factory. In this system there is one conveyor and some boxes are moving on the conveyor. Now our requirement is to count boxes moving on the conveyor. So for that we have done mechanical arrangement near to conveyor belt. In this mechanical arrangement one sensor is mounted so when box will pass through this sensor, it will cut the beam and

 

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 programming define the digital inputs and outputs and also prepare list of memory coils.

 

Digital inputs:-

ON/OFF Switch=I0.0

Box Detector=I0.1

Digital Output:-

Conveyor=Q0.0

M memory:-

M0.0=Reset















PLC program Explanation:-

In network 1, we have taken NO contact of ON/OFF switch to operate conveyor so when ON/OFF switch (I0.0) is pressed, conveyor (Q0.0) will be ON.

In network 2, we have taken counter logic. When conveyor is running the box will start to move so box detector (I0.1) will count parts and 200 parts completed then production completed (M0.1) command will on.

We have used NC contact of production completed (M0.1) memory bit so when part completed it will stop the conveyor.