Forward and Backward Scheduling

[Former Member]

I have a couple of related questions.

1. Where can I configure if I want Forward/Backward Scheduling in Customization? and if I leave it blank will it do forward or backward scheduling?

2. Does the system not perform backward scheduling if Replenishment Lead Time (RLT) is setup? If yes why?

[Former Member]

Hi,

System actually calculates delivery date by Backward scheduleing method first, Incase delivery date lies in the past, then system carries out forward scheduling. There is not customisation settings.

We can control whether system can perform backward scheduling only to certain extent in T.Code: OVLY.

Please note that, when we activate this system may confirm the delivery date in the past.

As far as the RLT is concerned, It does not control the scheduling type, if set it will propose a delivery date considering the RLT period.

Hope this helps.

Regards,

Sharan

[Former Member]

If RLT calculates its own thing rather than forward/backward schedule; that means that the date is first proposed by backward scheduling and using RLT if the material is available it is "kind of a backward scheduling" but if the required MAD can not be met still, the system then goes to the end of RLT and declares that as the MAD and calculates rest of the dates accordingly hence making it a "kind of forward scheduling"? Please clarify because the job of RLT is to commit the stock if it is available on the required date ignoring the Sales Requirements of the future (already made sales orders and perhaps outbound deliveries too?).

Furthermore, I still have one confusion. What if the "Delivery Scheduling" and "Transport Scheduling" are left blank and the system does the backward scheduling - how does it do it? Because with no Pick/Pack time and Loading time to calculate Material Availability Date (MAD) and Loading date and no Transportation lead time and Transit time, what is left to carry out the backward scheduling out with?

Even with forward scheduling the system needs these times and dates for the proposed delivery date of its own? Kindly help.

Edited by: shabie on Nov 14, 2011 6:38 AM

[former_member223981]

The system works as follows (In this sequence):

> A requested delivery date is entered

> A Backwards Scheduling is executed, which determines GI Date, Loading Date & Material Availability Date

> If the system has determined dates in the past, and your customising does not allow this, the system will trigger a forwards scheduling, starting with the current date as the material availability date.

So lets say scheduling determines a material availability date = 20th Novemeber; this should be considered a requested material availability date.

> The system then executes the actual availability check

> If the required quantity is not available on November 20th, the system looks to other dates where it is available.

> If the quantity is not available anywhere and you are using RLT, the system will go out as far as the RLT and confirm after this date; everything is considered available after the RLT - this is the purpose of the RLT function.

The purpose of RLT is not to "RLT is to commit the stock if it is available on the required date ignoring the Sales Requirements of the future"

"What if the "Delivery Scheduling" and "Transport Scheduling" are left blank and the system does the backward scheduling - how does it do it? Because with no Pick/Pack time and Loading time to calculate Material Availability Date (MAD) and Loading date and no Transportation lead time and Transit time, what is left to carry out the backward scheduling out with?"

It doesnt; the system will not execute a backwards scheduling in this case. The system just takes the date from the requested delivery date and populates the scheduling dates.

[Former Member]

When you say "Everything is considered available after RLT" What exactly does EVERYTHING include? Its only stock that matters because rest of times required (like loading time and transit time) are determined by different factors and does not need consideration in the first place since the system just adds up all the different time duration to give the final date of delivery.

Am I getting something wrong here?

Come on guys, write me up a small reply please? The forum has never disappointed me. Why do it now? Can anyone tell me the full meaning of EVERYTHING in the last post? That is all I ask!

[former_member223981]

By "everything", I meant all requirements outside the lead time are considered available.

[Lakshmipathi]

Where can I configure

It is in OVLY

G. Lakshmipathi

[Former Member]

Hi,

Backward scheduling is the calculation of deadline dates: the arrival time at the customer site is calculated as the earliest

possible goods receipt time at the customers unloading point on the requested delivery date. All four of the delivery and

transportation scheduling lead times are subtracted from the customeru2019s requested delivery date to determine if this date can

be met.

The transit time, loading time, and pick/pack time are subtracted from the customeru2019s requested delivery date to calculate the

required material availability date.

The system calculates backward scheduling as follows:

Requested delivery date minus transit time = Goods issue date

Goods issue date minus loading time = Loading date

Loading date minus transportation lead time = Transportation scheduling date

Loading date minus pick/pack time = Material availability date

Forward scheduling is also done if no product is available on the material availability date calculated by backward

scheduling. The system does an availability check to determine the first possible date when product will be available. This

new material availability date forms the starting point for scheduling the remaining activities. The loading time, pick/pack time,

transit time, and transportation lead time are added to the new material availability date to calculate the confirmed delivery

date.

Regards

Ram

[Former Member]

Note quite the answer I was looking for but thanks all the same. I actually know all this stuff.