Single tank level controlling with alarm controlling (S7-300 LAD).

This is PLC Program for single tank level controlling with alarm controlling.

 Problem Description:-

We need to control the level of water in the tank. Control the water level by simple PLC logic. Give the alarm for high level in the system and acknowledge button for the alarm reset .Write the ladder diagram logic for this application.

Problem Diagram

Problem Solution

To solve this this example we are using PLC programming. Here we have a tendency to use 2 sensors for level measurement, one is for prime level and second is for low level.

We use feeding valve for feeding Cycle for the tank and discharge valve for discharging cycle for the tank. Each valve are controlled by sensors. So once the water level goes below low level then feeding valve can activate mechanically and water level senses the high level then discharging method are activate mechanically.

Program

Here is PLC program for single tank level controlling with alarm controlling using PLC.

List of inputs/outputs

Digital inputs:-

Main switch:-I1.1

Start button:-I0.0

Stop button:-I0.1

High level:-I0.2

Low level:-I0.3

Feeding valve:-Q0.1

Discharge valve:-Q0.2

 

Digital outputs:-

Master coil:-Q0.0

Feeding valve:-Q0.1

Discharge valve:-Q0.2

Mixer motor:-Q0.3

 

Ladder diagram for single tank level controlling with alarm controlling using PLC.

Program Description

In network 1 we tend to used latching circuit for master coil ON (Q0.0) output.it will be started by pressing START Push button (I0.0) and stop by pressing STOP pushbutton (I0.1).

When cycle are going to be begin then system check level of the tank. If tank level is low then then feeding method can begin and tank level is high then Discharge cycle can begin.

Here we've taken NO contact for each sensors within the program for simplicity. It will be done by relay logic in field otherwise you will choose such variety of sensors.

In network 2,when tank can observe low level then low level sensor (I0.2) is going to be activated and feeding cycle are going to be ON. Here we've taken NC contact of high level sensor (I0.3) therefore once PLC can observe high level then it'll STOP feeding cycle.

In network 3,when tank can observe high level then high level sensor (I0.3)  is  to be activated and discharging cycle are going to be ON. Here we've taken NC contact of low level sensor (I0.2) therefore once PLC can observe low level then it'll STOP discharge cycle.

In network 4, mixer motor (Q0.3) will remain ON when discharge valve is ON.

In network 5 when high level (I0.3) is detected, alarm (Q0.4) will be activated.

In network 6 when acknowledge button is pressed, alarm will be reset.

 

Note:-Application is only for learning and educational purpose .Above application may be different from actual application. This application can be done in other PLC also. Users are responsible for correct operation of the PLC system and for any possible injuries and or material damages resulting from the use of this program. It is necessary to take care of safety during implementation, installation, maintenance and operation.

 

All parameters and graphical representations considered in this example are for explanation purpose only, parameters or representation may be different in actual applications. Also all interlocks are not considered in the application.