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Hi All,

 

I’ve been looking at a scenario where Master Scheduling is being used in conjunction with Order Gap time, but I’m struggling to understand the logic of how MPS is generated. 

 

I’ve set up a simple example in my test environment (24R1) to demonstrate:

 

Max Lot size = 10

Order Gap Time = 1 (just to simplify - in reality this would be different hence why rate by period hasn’t be set up)

Test 1 - Works as I would expect - the MPS generation stops at the PTF, so the system cannot keep the Projected balance positive and an Action Message is generated.

 

Test 2 - However, if I split the forecast into 2 overlapping periods, the Order Gap time rule is ignored and multiple MPS/SORs are generated on the same day and the project balance is now always at 0 or above.

If I add a large forecast at the PTF, I get a strange pattern, I think where each demand entry (forecast) is searching back for a free day, hitting the PTF and creating one SOR for the max lot size. However the overlapping demands are not considered, so the order gap time is not followed.

 

Is this intended system behavior? Or is there a logic that needs to be followed carefully when using order gap time and Master Scheduling?

 

Thanks in advance for any comments/ideas.

Hi Katie,

Order Gap Time work the same way in MRP as in MS. Well the difference is of course the PTF rule that cuts in in MS. Here below you see a result of an MRP planned part with max lot size of 20 pcs and an Order Gap Time of 1 day:

So at the 9th of September I get 3 SORs. The Order Gap time functionality is not that fancy as you may think it is. It does not put a max capacity limit per day. In MRP you can to some extent “mitigate” this behavior by using planning method G - Order Cover time. In MS you cannot use G as a planning method. I do believe there is an open idea in the Community to be able to use G in the MS Level 1 Calculation.

Best Regards,

Mats

Thanks Mats that is very helpful,

 

Ah ok that’s clear now - so basically the MS calculation is working out the projected balance each day, if this is negative (or below Safety stock) supplies are generated in line with the max lot size & order gap rule up to the PTF. However the MS calculation for the next day will generate another set of supplies up to the PTF if the projected balance is still negative.

 

So the order gap rule is applied to each day’s calculated supply, but not collectively, so this is why you get overlapping SORs.

 

I re-created in excel step by step for my own understanding and have attached in case it is useful for anyone.

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