Make test mode and manual mode in the system.

Application:-There are two valves in the system and two valve should be operated in test mode and manual mode also. Write the PLC program for this application using ladder diagram language.

Explanation:-

As per above application, there are two valves in the system and we want to ON/OFF valves as per selected mode. We have taken one selector switch for test and manual mode selection. Test mode will work only for testing function like mechanical block or function of valve. Manual mode work with all interlocks which are required for manual function like both valve should not on together.

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 is digital input and valves are the digital output. So define digital input address and output address as per below explanation,

Digital inputs:-

Test/Manual Mode=I0.0

Valve 1 ON/OFF=I0.1

Valve 2 ON/OFF=I0.2

 

Digital Output:-

Valve 1=Q0.0

Valve 2=Q0.1

PLC program Explanation:-

In network 1, we have used the test and manual mode logic. If manual mode (I0.0) is on and valve ON/Off (I0.0) switch is on and valve 2 is off then valve 1 (Q0.0) will be ON.

If test mode is selected and valve 1 switch is on then valve 1 will be ON.

In network 2, we have used the test mode and manual mode logic same as network 1

If manual mode is selected and valve 2 switch is on and valve 1 is off then valve 2 will be ON. And if test mode is selected and valve 2 switch is on then valve 2 will be on directly.

Hence in manual mode interlock is required between two valves but in test mode we can test valve easily without interlock.