Programmable Logic Controllers

1. Programmable Logic Controllers Day 3 Presentation Innovative Uses Of Timers

2. Agenda Timer Example Problems Other Types of Timers Engineering Technology

3. Timer Examples • On Delay: Output B comes on at a specific set time after output A is turned on. When A is turned off, B goes off. • Off Delay: Both A and B have been turned on at the same time. Both are in operation. When A is turned off, B remains on for a specific set time period before going off. • Limited On Time: A and B go on at the same time. B goes off after specific set time period, but A remains on. • Repeat Cycling: An output pulses on and quickly off at a constant preset time interval. • One-Shot Operation: Output B goes on for a specified time after output A is turned on. Output B will run for its specified time interval even if A is turned off during the B timing interval. Engineering Technology

4. Timer Examples • Alternate on and off of two outputs: Two alternately flashing lights. The time for the two lights could be different. • Multiple On Delay: Two different events start at different time intervals after an initial starting time reference point. • Multiple Off Delay: Two different functions remain on for two different time intervals after a process is turned off. • Interval time within a cycle: We may require that an output come on 7.5 seconds after system start up, remain on for 4.5 seconds, and then go off and stay off. Engineering Technology

5. Timer Example 1 On Delay: Output B comes on at a specific set time after output A is turned on. When A is turned off, B goes off. Engineering Technology

6. Timer Example 2 Off Delay: Both A and B have been turned on at the same time. Both are in operation. When A is turned off, B remains on for a specific set time period before going off. Engineering Technology

7. Timer Example 3 Limited On Time: A and B go on at the same time. B goes off after specific set time period, but A remains on. Engineering Technology

8. Timer Example 4 Repeat Cycling: An output pulses on and quickly off at a constant preset time interval. Engineering Technology

9. Timer Example 5 One-Shot Operation: Output B goes on for a specified time after output A is turned on. Output B will run for its specified time interval even if A is turned off during the B timing interval. Engineering Technology

10. Timer Example 6 Alternate on and off of two outputs: Two alternately flashing lights. The time for the two lights could be different. Engineering Technology

11. Timer Example 7 Multiple On Delay: Two different events start at different time intervals after an initial starting time reference point. Engineering Technology

12. Timer Example 8 Multiple Off Delay: Two different functions remain on for two different time intervals after a process is turned off. Engineering Technology

13. Timer Example 9 Interval time within a cycle: We may require that an output come on 7.5 seconds after system start up, remain on for 4.5 seconds, and then go off and stay off. Engineering Technology

14. Other Types of Timers and Bits Retentive Time On Time Off Time On Timing Bit Timer Enabled Bit Engineering Technology

15. Next Class! Counters Engineering Technology