PLC SCADA ACADEMY

July 16, 2020

Pump control with pressure switch.

Pump control with pressure switch.

Application:-There is pump in the system and it is generating pressure inside the part with water. So as per our requirement we set pressure in the pressure switch is 5 bar and we need to turn off pump after pressure achieved. Write PLC program for the application using ladder diagram language.

Pump control system

PLC

Control panel

Start

Stop

Pump

Pressure switch

Pump trip

Explanation:-

Here in above application we have used pump motor for pressure. When start button is pressed, pump will start and generate the pressure in the pipe. Our pressure switch setting should be 5 bar so it will generate digital signal when set pressure achieved.

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 and pressure switch are digital inputs and pump is the digital output. So let’s define digital inputs and outputs for the application.

Digital inputs:-

Start=I0.0

Stop=I0.1

Pressure switch=I0.3

Digital Output:-

Pump Motor=Q0.0

PLC program Explanation:-

In network 1, we used pump on operation. When start button is pressed, pump will be on if pressure is low.

In network 2, we used pump motor off operation. When pressure achieved, pump will be stop. If stop button pressed, pump will be stop.

June 28, 2020

Clock memory function in the S7-1200 PLC.

Clock memory function in the S7-1200 PLC.

Application:-Understand the concept of clock memory and system memory function in the S7-1200 PLC using example

Explanation:-

To understand the system and clock memory we can use S7-1200 PLC. Clock memory configure byte and that cycle of individual bit on and off at fixed interval. These bits can be used in the program for controlling or for some time based logic. We can use these bits for triggering function.

PLC program:-

Select clock memory and define address in the hardware confugration.For example take byte 0 for clock memory so form M0.0 to M0.7 can be used for clock pulse.