Dynamic negative days


I’m trying to understand why Master scheduling is creating a new planned purchase order, where I believe it should not, based on the fact that I have flagged ‘Use dynamic negative days = Yes’. Following is a very simple example:

My product is Min/Max controlled (min=10, max = 20). Fulfill minimum = Today’s date + Lead time

Today, March 23rd, there is no stock of the item. There is a sales demand of 7 pieces on March 29th

Lead time is 10 working; Purchase in multiple of 5; negative days is 5

After running master scheduling the system shows a planned order of 30pcs (requirement date April 10th, generating a future message given the lead time). This covers the sales demand, and the min. stock and replenishes to the maximum stock level (rouded up to nearest multiple). This is fine. Then the planned order is firmed.

Master scheduling then runs again. This creates a NEW planned order for 30 pcs. (There is an action message to reduce the firmed order from 30 to 10?). However, I expected NO new planned order as there is a firmed order due on April 10th that should still cover both the sales demand and min. stock, given that Use dynamic negative days = YES. By the way, if I change the negative days in the coverage group from 5 to 15 (more than lead time) I get the expected result… (i.e. no new planned order). I thought however that the dynamic negative days functionality should take care of this.

Any thoughts or perhaps a setup thing I might have overlooked.


I’m afraid this is not possible, at least in AX 2012 R2. This functionality of dynamic negative days works for all other coverage types except Min\Max. If you check code under \Classes\ReqSetupDim\maxNegativeDays, you’ll see this condition (line 16). I guess that was done to accomodate the Min\Max rules (seasonal fluctuations, for example) and don’t let them to be distracted with the lead time setups. I know, that does not help much, but maybe it is a time to cinsider another coverage type, for example, Requirement + min order qty that should give you your max qty during the planning.

Thank you Grygory for your investigation and sharing your findings!

I reported the issue to MS and they have provided me with a hotfix (see info below)


KB Article Number (s) : 2875555

Language: All (Global)

Platform: i386

Location: ( http://hotfixv4.microsoft.com/Microsoft%20Dynamics%20AX%202012%20R2/nosp/KB2875555/6.2.1000.2318/free/466404_intl_i386_zip.exe )

NOTE: Be sure to include all text between ‘(’ and ‘)’ when navigating to this hot fix location!

This is an Application hotfix.