Basic PLC Ladder Programming Training Examples for Beginners. Hi Friends here we are starting a series of Free Training on PLC Ladder Programming. These PLC Ladder Programs are important to get basics of Ladder
Programs
PLC Ladder Practice Problem:
Basic PLC Ladder Programming Training Example 14
Using 3 counters together with the flag of M1013 (1s clock pulse) to operate a 24-hour clock.
Topics Covered in this example is use of Counter in PLC Program
Number of PLC Counter Required
C0 – count per second
C1- count per minute
C2 – count per hour
Number of PLC internal memory flag Required
M1013 – 1s clock
PLC Ladder Programming:
PLC Ladder Programming Description:
The key of operating a 24-hour clock is to use M1013 (1s clock pulse). When the program is executed, C0 will count once per second. When the counted number reaches 60(1 minute), C0 = ON. C1 will count once, and C0 will
be reset at the same time; similarly, when the counted number in C1 reaches 60(1 hour), C1 = ON. C2 will count once, and C1 will be reset at the same time. Furthermore, when the present value in C2 reaches 24, C2 will be reset, and the 24-hour counting process will start again. The 24-hour clock operates by using C0 to count “second”, C1 to count “minute” and C2 to count “hour.” In this clock, the value of “second”, “minute” and “hour” can be read by C0, C1 and C2 correspondingly. When the set value of C2 is 12, the clock will be a 12-hour clock.
