Question

APB Need date as a hard constraint, Fixing plan, Unscheduled vs Infinite scheduled operations

  • 13 May 2021
  • 5 replies
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Hello all,

I have 3 questions related to APB:

  1. I am wondering whether it is possible somehow to setup and/or use functionality of APB in order to fulfill need date everytime (consider need dates as a hard constraint). This can lead to situations when operations of the shop order are scheduled partially to the past. I am expecting that the answer is NO, but I just wanna be sure that I haven’t missed anything.
  2. Possibilities of fixing scheduled operations in the schedule - presuming these:
  • fixing based on the shop order operation state - do not schedule the released operations
  • fixing by the time fence given by an offset of hours from now/sysdate - configurable from the basic data
  • anything else?
  1. What is the difference between the automatic scheduling of Unscheduled operations and Infinite scheduled operations.

Thanks for your advices.

 

Best regards,

Zdenek Baumelt

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5 replies

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Hi @zdenek.baumelt ,


To answer regarding possibility of  fixing a time fence given by an offset is possible to do using shop order scheduling basic data>Scheduling Settings. 


There you can define the scheduling start point.

 

Regards,

Naveena

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Dear Naveena, 

thanks for Your picture related to question 2. This figure is depicting one of 2 options that have been mentioned in the question how to fix the plan in APB. If more, please describe which one…

Best regards,

Zdenek Baumelt

MBENSE
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In APB, you can modify the current now time, i.e the time that APB thinks that the clock is when scheduling the operations. If you set this date/time value to a very early date (like first of January in my example), and then reschedule the operations, all operations will meet its need date (as long as they are a bit later then first of January), When you save back to database, some of the operations will end up as past due, since they are scheduled in the past!

You can find the this In APB Menu - Tools- Settings:

 

/ Martin
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Dear Martin,

 

thank you very much for Your response to the question #1. I have missed this settings, it works, this is exactly what I have looked for!

Regarding question #2 I am assuming that there is no other option how to freeze schedule.

Regarding question #3, could I ask You to clarify the difference between Unscheduled and Infinite scheduled operations? From my point of view, Unscheduled are really Unscheduled in APB, while Infinite scheduled are scheduled by an in-built IFS planner.

 

Once more thanks!

 

Have a nice weekend,

Zdenek

MBENSE
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To be able to freeze the schedule, you could do as you have suggested. I.e. when rescheduling operations, exclude the released once. Another option is to select only a subset of the operations and reschedule only those. (like select all orders scheduled from next week or similar). Also not loading all operations is an option, but then APB will not be aware of those, and then you could extend the offset for earliest possible start time, to make sure you are not overbooking the resources in now time.

The unscheduled operations are operations that the APB scheduler has tried to schedule, but was not able to find a slot where all constraints were fulfilled. This could be a material constraint can not be fulfilled, the labor class does not have any employees (capacity) or the calendars of the constraints does not overlaps enough. those operations are not plotted in the Gant chart, since they don´t have a gap between start and finish. Unscheduled operations are not producing any load, i.e. when saving back to database, those operations will not be shown in the load charts etc.

Infinite scheduled operations, are the operations that has been scheduled by infinite scheduler (the normal scheduler that schedules the operations when the shop order is created). Since the infinite scheduler does not consider load from other orders, it can overload a finite work center. Therefore, when loading such operations into APB, it is important to reschedule them, if you want to make sure to create a finite schedule. The infinite scheduler also have other limitations, i.e. it does not consider labor or tools when scheduling.

/ Martin
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