timers

roddbodd · Sep 24, 2004

i am trying to set up two seperate on off timers. the process is on a dust baghouse. a burst of air shoots into the bags to clean them. there are two sets of air valves. i need to have one come on for half a second 2 min. after the motor is started. then i need to wait for 15 min. and have the other come on for a half a second. then wait for 15 min. and start the process over. this process will be repeated until the motor is turned off. i have a program that is working but i have to get my times set a certian points or they will start overlapping each other.

thanks
rodney

tom_stalcup · Sep 24, 2004

Sound interesting. What platform are you using?(GE, AB, etc)

roddbodd · Sep 24, 2004

i am using a sq d/telemacanique sr1 smart relay

tom_stalcup · Sep 24, 2004

I haven't played with the smart relays before, but after looking at the manual I think you'll need something along these lines....
1. the input from the motor feeds three separate timers, 2 min, 17 min, and 32 min.
2. the 2 minute timer will start a 1/2 second timer, and the 17 minute timer will start another 1/2 second timer.
3. The 32 minute timer will reset all three timers from step 1.
This is just my best guess..... You'll need to select with type of timer to use in each section. Let me know if this helped, or if I'm just telling you things you already know.....

Eric Nelson · Sep 24, 2004

Assuming this is a straightforward as you've explained, you can simply cascade timers to accomplish this. This ladder should be generic enough for a smart relay to handle:



|   MOTOR     TIMER

|    ON      #5 DONE     +---------------+

|----] [-------]/[-------| TIM 1         |  Delay before first valve

|                        |  (120.0 sec.) |

|                        +---------------+

|   TIMER

|  #1 DONE               +---------------+

|----] [-----------------| TIM 2         |  First valve duration

|                        |    (0.5 sec.) |

|                        +---------------+

|   TIMER

|  #2 DONE               +---------------+

|----] [-----------------| TIM 3         |  Delay before second valve

|                        |  (900.0 sec.) |

|                        +---------------+

|   TIMER

|  #3 DONE               +---------------+

|----] [-----------------| TIM 4         |  Second valve duration

|                        |    (0.5 sec.) |

|                        +---------------+

|   TIMER

|  #4 DONE               +---------------+

|----] [-----------------| TIM 5         |  Delay before restart

|                        |  (900.0 sec.) |

|                        +---------------+

|   TIMER     TIMER

|  #1 DONE   #2 DONE

|----] [-------]/[--------------(VALVE #1)

|

|   TIMER     TIMER

|  #3 DONE   #4 DONE

|----] [-------]/[--------------(VALVE #1)

beerchug

-Eric

tom_stalcup · Sep 24, 2004

Or you could go with Eric's much cleaner and easier code.......

Eric Nelson · Sep 25, 2004

tom_stalcup said:
Or you could go with Eric's much cleaner and easier code.......

Cleaner? Easier? Your idea achieves the same end result, and that's all that matters...

beerchug

-Eric

tom_stalcup · Sep 25, 2004

I wasn't sure how limited the smart relay ladder codes were, so I tried to come up with something that would work with 1 control bit per rung.... These things look fairly interesting, I might need to pick one up to play with.

roddbodd · Sep 25, 2004

thanks to tom and eric for your help! i was making this thing harder than i should. i was right there except for having a timer to reset the cycle.

thanks again
rodney

timers

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