Stickman47 (Customer) asked a question.
I have a small project that I need help with. My background is in Allen Bradley but I have this Directlogic DO-05DR that I need to get through. I need a cycling timer that is on for 30 seconds and off for one minute, that re-cycles continuously.
I have tried several versions with two timers, but I can not figure out how to re-start the "ON" cycle timer once the off time is done. Can anyone help?
Use one timer. Enable with a N/C of the timer output bit. Use a preset of 900. Your controlled output is controlled by a rung with the counter accumulator being less than or equal to 30.
There are always lots of ways to program, each with its advantages and disadvantages. bcarlton listed a good way. Here is another. When C1 turns on, C2 will be OFF for 600 tenths of a second (60.0 seconds), then C2 will turn on 300 tenths of a second (30.0 seconds), and then repeat until C1 turns off. These timer setpoints (600 and 300) could also be V-memory locations, where they could be adjusted from the HMI (if there is an HMI). If the output must first be turned on when C1 turns on, then an additional rung could be added to use N.C. contact of C2 and output to C3 for example, and the timer setpoints would be swapped. The TMR instruction setpoints can only go to 9999 (999.9 seconds).