http://hi.baidu.com/einsteinalbert/blog/item/6a39629ba58f7aa9c9eaf4ba.html[@more@]

Basically,MRP needs keep the balance for Supply/Demand.
The planning process calculates net material requirements from below Supply/Demand:
Supply:
- On hand (Nettable inventory)
- Approved PO/PR
- Planned order(the status shows as 'Release')
Demand:
- Negative On hand (Nettable inventory)
- Planned order demand
- Discrete Job demand
- Safety Stock
In addition,MRP Gross requirements ignored the demand of purchase item negative On hand,only give the suggested planned order quantity in 'Planning details report'. but it will consider the demand of finish good item negative On hand and will be generate planned order after MRP runs.

理解Planning Details Report？

1）Nettable Inventory:MRP初始数量。
2）Gross Requirements:毛需求　
3）Scheduled Receipts:计划接收数量
4)Planned Orders：MRP建议的已计划订单。
5）Projected Available：MRP计划后的可用量　
6）Current Scheduled Receipts：当前的计划接收数量（即未按MRP　Rechedule建议）
7）Current Projected On Hand:当前的计划在库（即未按MRP　Rechedule建议的在库）
8）Safety Stock：安全在库。　　
重点在于检查1)、2)、3)、4)、5)、8)的数值

Horizontal material Plan画面解释

1 采购订单：已存在的采购订单，其日期为MRP Due Date(即PO　neey by date-PO lead time).
2 正在接收：表示已接收但未入库的状态。只在MRP运行当日栏位显示。
3 当前计划的接收：MRP　Due Date，MRP视其为计划库存。
4 计划可用余额：等于合计供应减毛需求。
5 计划现有量：等于当计划的接收加上前一日计划现有量再减去毛需求。

Desc MRP Supply and Demand