Weeky Schedule in RsLogix 500

Hi, I’m having a hard time wrapping my head around creating a weekly schedule for a pump to turn on.
Setup:
Micrologix 1400 1766-L32BWAA RsLogix 500

The pump schedule is Monday thru Sunday and the pump is to turn on at 20:00 hrs and off the next morning at 3:00. The attached logic screen shot is only for Sunday, and if I enter hour 3 in to the off time this will not work due to the day advancing to 1=Monday. Can anyone help?

Start a timer at 20:00 hrs with a preset of 7hrs and run the pump for 7 hrs.

First rung:
On Sunday the pump runs from 20:00 till Midnight.

Second rung:
On Monday the pump runs for 0:00 till 3:00 and from 20:00 till midnight.

Third rung
On Tuesday the pump runs from 0:00 till 3:00 and from 20:00 till midnight.

Fourth rung
On Wednesday the pump runs from 0:00 till 3:00 and from 20:00 till midnight.

etc.

@TConnoly, each day may have diffrent on time off time settings for the pump to turn on and off.

Thats fine, the same method can handle different times. The general idea I'm trying to get across is to handle each day separately instead of trying to handle a midnight roll over. Write it either using words or make a timing chart, day by day with your start and stop times. Any midnight crossing is a stop for that day and a start for the next day. From there it should be easy to program the rungs.

You can use a start time in hours and have the operator enter the duration time of the pump run time

Thanks, for you help.

@TConnolly can you please post an example of the logic when you get at chance. Thank you.I used the logic that Mickey and Adam303 posted but I really want to use the off time as an actual hour, and I'm not fully understanding your concept of doing this.

Will each run of the pump start late in one day and run past midnight until sometime early in the next morning? That would be easier. If it could be any time to any time then it's a little more complicated. We need to have a handle on the range of possibilities.

I see three cases:

1. If Stop time > Start time, start today and stop today.
2. If Stop time < Start time, start today and stop tomorrow. This includes stop at midnight, 12:00am or 0000 hours.
3. If Stop time = Start time, this is the trivial case where the pump never runs.

You can use the day of week to point to arrays of start and stop times, but freeze the pointer while the pump is running.

I wonder why no one has suggested using a 7 day minute value

Timer = 0 to 7 * 24 * 60 -1 (Max Value is 10079)

Value is calculated from the RTC
(DOW * 24 * 60 ) + HR *60 + Min

Logic is now just GRT OR LES a value that spans a week

On Time and Off Time are also calculated based on settings - Up to the programmer to create the ON/OFF comparison values for each time
EG On Time = 10 pm DOW 0 to 4 gives 5 on times
Off Time = 3 am for DOW 1 to 5 gives 5 off times
eg
IF Time >= On1 and time < Off1 OR
Time >= On2 and time < Off3 OR
Time >= On3 and time < Off3 etc
Then Pump is on
Else Pump is off

GEQ  -----LES  -----|-----(Pump ON)

Timer     Timer     |

On1       Off1      |

                    |

GEQ  -----LES  -----|

Timer     Timer     |

On2       Off2      |

                    |

GEQ  -----LES  -----|

Timer     Timer     

On3       Off3      



ETC

Only hard part is a pump that starts before the end of the week and then must continue running into the start of the next week
one way to do this is use two comparisons one for the start of the week the other for the end of the week

Start of the week is On1 = 0 Off1 = ???

End of the Week On19 = ??? Off19 = 10080

Will each run of the pump start late in one day and run past midnight until sometime early in the next morning? That would be easier. If it could be any time to any time then it's a little more complicated. We need to have a handle on the range of possibilities.

Click to expand...

Bernie the pump run times will be as follow for each day of the week

DOW On Time Off Time
Sunday 1:00 5:00
Monday 20:00 3:00
Tuesday 20:00 3:00
Wednesday 20:00 3:00
Thursday 20:00 3:00
Friday 20:00 3:00
Saturday 18:00 4:30

Although it may initially seem more complicated, using a sequencer is a great was to accomplish this. I have several set up for things like automatic temperature and pressure set-back that you just can't rely on employees to do on a regular basis. The nice thing about a sequencer is that you can use an HMI to form a graph with hours on the horizontal axis and days of the week on the vertical. Assigning a indicator pushbutton to each block alloows multiple schedule changes in a day if the need ever arises. Easy for anyone to change, too.

Can you guys give your opinion on the attached logic for the schedule.