This is a PLC Program for Blinking (ON/OFF) lamp at 5 seconds interval.
Blinking Lamp
Problem Description
Make the Indicator or lamp ON after five seconds and OFF after five seconds.
Make a program which switch ON lamp for 5 seconds, then OFF for 5 seconds, then ON for 5 seconds & again OFF for 5 seconds, and so on.
Problem Diagram
Problem Solution
This problem can be solved by using timers. In this case we will use TON (ON Delay Timer).
For explanation we consider one SWITCH for enabling the ON/OFF cycle and one lamp for output.
When user presses the SWITCH then lamp will energize and remains ON for 5 seconds after that it will OFF for 5 seconds. This cycle will repeat itself.
List of Inputs & Outputs
Inputs List
- SWITCH : I0.0
Outputs List
- Lamp : Q0.0
M Memory
- M0.0 : bit memory for lamp OFF condition.
PLC Ladder Diagram for Blinking Lamp
Program Explanation
In this problem, we will consider S7-1200 PLC and TIA portal software for programming.
Network 1:
In this network when SWITCH (I0.0) is pressed, when the lamp OFF condition is not present then the lamp (Q0.0) will be ON.
So here we used NO contact of SWITCH (I0.0) and NC contact of lamp OFF condition (M0.0).
Network 2:
In this network when lamp (Q0.0) is ON then TON (ON delay timer) instruction will be executed and it will set the lamp OFF condition.
So we have taken here NO contact of lamp (Q0.0), TON timer and programmed time is 5 seconds.
Network 3:
As per our condition, lamp OFF condition (M0.0) should be OFF after 5 seconds delay, so we have used TON again.
So we used NO contact of lamp OFF condition (M0.0) and TON with 5s programmed time.
Result
