Low Level Code

Dear all,

I have a Finished good A with an assigned production BOM made out of components x, y and z.

I have another finished good B with an assigned production BOM made out of Components x, y, z and w. In this case component y is made out of z and w.

I understand the LLC of component z is 1 in the A production BOM and 2 in the B production BOM.

So how are these LLC(s) used in terms of proving the statement ‘Planning system works by the order of the low-level code’? please explain.

Thanks in advance! Ilak

An item can be in different levels in BOM’s therefore you can have mixed requirements. Systems handle this by assigning a low level code to the item, this will be the lowest position in any BOM. When the planning engine begines its calculations it starts with all the items in the lowest code, and works upwards, in this manner it does not miss any demand for an item.

Appreciate your quick response Adam.

So do you mean the Planning Engine lists me all the LLC=0 items in the first lines on the planning worksheet and then LLC=1 and so on? Is that accomplished by the order of the items listed on the planning worksheet?

If so, when I run the planning engine for my example posted in original question, it lists me A, B, x, y, w and z in order. But according to the example, w is assigned the highest level and I would expect it to be listed at last in the planning worksheet.

Please correct me… Many Thanks!


It is irrelevant to the presentation of the results. It is how it calculates behind the scenes the bundling ensures that all supply and demand regarding the item is processed at the same time - if you calculated this in item order then the routine would take a lot longer to run.

Now I can understand this is calculated behind the scene and can imagine how long it would take if it it’s calculated in item order as you explain.

But still I’m unable to picture the way it calculates according to the LLC. I’m trying to think if there was a demand for 2 items, then system would go to each item’s production BOM and calculate the demand for each component. Assuming a similar component is being used in both BOM’s at different levels how would you explain this?

Would you mind explaining using this example?


Well think of an item, this item has sub-assemblies. The top level is 0. At level 1 you need 6x item 0001HEX-NUT. There are sub-assemblies, and one of these has one level, at this level (2) you need 4x item 0001HEX-NUT. Another sub assembly at level 1 has a subassembly at level 2 that within it at level 3 you need 10x item 0001HEX-NUT.

The total requirement for the item 0001HEX-NUT is 20. With the low level code approach the system would see the requirement as 20 by netting the requirements. The alternative would be to start at the top and blow down through each level, the system would get to 20, but by going up and down the demand and supply chain.

Basically the system will process from one low level to the next, It will start at 0 and head down. This will ensure all of the gross requirements are passed down before the MRP record is processed. This means the component parts are always planned with needs of all higher level parts considered. In the example given without LLCs the system would blow down from level 0 and find a subassemnly, blow through this until it finds the item 0001HEX-NUT at level 3, this would need to be stored whilst the process went back to level 0 and started the downward search again for more of the item 0001HEX-NUT. With LLC’s this exhaustive searching is greatly reduced.

Very clear now. Appreciate your great help!