Well,
When you use item coverage, it applies with Master Planning.
First you need to understand the Coverage Group concept.
This is the most important structuring setup, from my point of view, for master planning for items.
Coverage group defines how stocked items have to be managed when planned orders are generated by the master plan.
You have to define a coverage group for each item that will be use within master planning (you will choose the policy like Min/Max, Period, etc).
Note that you can default one in the master planning setup.
After that, you can work at a finest level for each item, that is called item coverage.
When your coverage group is setup with the Min/Max policy, you have to finish the setup by using item coverage.
For each warehouse/Site, you will specify what is the min level acceptable (e.g. security stock) for that stock dimension and the also the Max acceptable.
Example : in the warehouse WH, item A is a physical item. You have setup min to 50 and max to 200.
T0 : you have 150 in stock.
T1 : you are running the master plan for item A -> nothing happens.
T2 : you setup a SO for 50 and process it (you have 100 in stock)
T3 : you are running the master plan for item A -> nothing happens.
T4 : you setup a SO for 60 and process it (you have 40 in stock)
T5 : you are running the master plan for item A -> a planned order is generated for 160, as the min is reached, to replanish the stock until the max is reched, you will have 200 in stock at the end.
That's it.
