As we know purchasing order acknowledgement is vendor confirmation.
https://help.sap.com/saphelp_46c/helpdata/en/75/ee13f555c811d189900000e8322d00/frameset.html
http://www.cnblogs.com/jefflu2012/archive/2013/07/25/3214774.html
http://blog.163.com/chengzhi_vang/blog/static/5661858920144152555107/
一、說明 Definition
很多時候，下了PO都希望知道Vendor是否能夠按照我們PO要求交貨，這里就需要Vendor給一個確認。Order Acknowledgement就是在PO中維護這些確認信息的功能。
當然這些信息可以手動維護，也可以透過EDI有Vendor的系統回傳回來。
Acknowledgement信息包括
1. order acknowledgements
2. loading or transport confirmations
3. shipping notifications
二、目的Purpose
1.使用訂單確認，物料計划就不會僅僅依賴采購訂單中的交貨日期和交貨數量或者框架協議中的計划行了，也可以追蹤物料需求計划；
2.一旦啟用Order Ack.功能，by PO收貨的時候就會只能按照確認的數量收貨；
3.可以通過多種方式確認訂單，即可以一步確認delivery date，或者分兩步，就是確認+出貨裝運確認，采用哪種確認是通過Conf. Control來控制的，
三、業務流程Business Process Flow
1.Order Acknowledge+Shipping Inbound Delivery
1.1 先做訂單確認
在采購訂單的Confirmation 這個tab下，Conf. control選擇0001，
然后CC（confirmation category）這個字段選擇“AB Order Acknowledge”，輸入交貨日期和數量等信息。
1.2 待供應商貨裝好后，建立Shipping Notif.
這個有兩種操作，一種是現在PO的confirmation頁簽下CC行創建一行LA的。然后用VL31N創建一個Inbound delivery；另一種是直接用VL31N創建一個inbound delivery，系統會自動在PO的confirmation頁簽下創建一行LA的數據，並將所有數據都填好。
1.3 GR（若存在inbound delivery,收貨就by inbound delivery,若沒有就by PO),這里收貨是否能用by inbound delivery，是CC這個在后台的配置控制的。
If you wish to post a goods receipt with reference to vendor confirmations, you should set the GR assignment indicator for the desired confirmation category in Customizing for Purchasing.
2.一步Shipping.Notif
這個方法和第一個相比，就是省去了Order Ackknowledge這一步，
2.1 Conf. Control這里選擇
2.2 輸入LA數據行，或者直接創建Inbound Delivery
2.3 GR
常用的就是這兩種。下面看后台配置。
三、后台配置Customize Configuration
Path:IMG-->Material management-->Purchaisng-->Confirmations
1.Define External Confirmation Categories
這里定義了Confirmation category,外部確認是針對供應商可能反饋的信息類別，比如針對PO的確認、發貨通知等
2.Define Internal Confirmation Categories
內部確認是企業內部將供應商確認信息進行分類，以確定哪些是訂單回執，哪些是裝運通知（可以創建內向交貨單的），哪些是粗收貨
Dlv Ty:Delivery Type,A classification that distinguishes between different types of delivery.The delivery type determines how the system processes a delivery. For example, depending on the delivery type, the system determines which screens to present and which data to request from the user.
Ret.Del.Vis：If you have set this indicator, any return deliveries created with MBRL for inbound deliveries are visible in the confirmation overview.**Visible return deliveries are only possible for inbound deliveries whose confirmation control key is set for GR assignment and whose previous goods movements were NOT posted using Inventory Management transactions。
3.Set Up Confirmation Control
1).Create Inbound Delivery:該標識如果勾選，則用戶可以運行VL34為分配了此確認控制的滿足條件的PO自動創建交貨單；附：如何分配默認控制類型給PO，后勤執行-->裝運-->交貨
這種自動創建內向交貨的前提條件是：
If your enterprise does not work with shipping notifications, or only uses them to a limited extent, you can generate inbound deliveries automatically from purchase orders.
2）POD相關：收貨時是否向供應商發送收貨回執作為Proof of delivery
POD Control (Proof of Delivery)
This indicator controls the POD relevance of a delivery item along with the delivery item category, that is to say, whether a delivery item is relevant for proof of delivery on the ship-to party side.
The indicator can have the following settings:
' ': not POD relevant
'A' : always POD relevant
'B' : only POD relevant when there are quantity differences
The indicator is copied from the purchasing or sales document into the delivery, if control of POD relevance in the delivery item category is set to "Copy POD relevance from preceding document".
》》》》》》》》》》POD相關的配置
路徑：Logistic Execution-->Shipping-->Deliveries-->Proof of devliery-->Set POD-Relevance Depending on Delivery Item Category
3)Qty.Diff.Profile
轉到Confirmation sequence.
1) MRP-relevant :MRP是否考慮此外部確認的數量,勾選了這個后，MD04中將會出現這個采購訂單的的交貨需求信息
2)GR-relevant:這個CC是否控制收貨，例如AB類型的不能收貨，LA類型的可以收貨，就是這個控制的；
Indicator: Confirmation is GR-Relevant
Specifies that the relevant confirmation category is cancelled out by a goods receipt.
Use
This indicator is needed to close transactions for materials planning purposes.
When goods are received against a PO, materials planning and control must know that this GR relates to the last confirmation you received.
This means that only one confirmation category can have the indicator 'GR relevant'.
Examples
If, for example, a GR of 200 pc of the material Steel 1 is entered against a PO item for 200 pc after an inbound delivery marked as GR-relevant has been posted, the inbound delivery is cancelled out by the goods receipt.
如果一個確認控制中的所有外部確認類別都不勾選“GR-Relevant”,系統會提示：
即最后一個確認類別必須勾選“收貨相關”，且只鞥勾選一個。
如果勾選了，則ＧＲ會沖減外部確認的數量，且內向交貨單一旦創建，如果訂單回執也是ＭＲＰ相關的，則內向交貨數量會沖減訂單回執數量，ＧＲ后，GR數量會沖減內向交貨數量。
3）收貨分配
Indicator: GR with Reference to Vendor Confirmation
In the case of a PO item with several confirmations, this indicator ensures that goods receipts are assigned to the relevant confirmation in each case.
Use
Assignment to confirmations received at the time of goods receipt (GR) means that the quantity from the associated confirmation will be suggested in the GR and that the GR reduces or cancels out precisely the relevant confirmation in the stock/requirements list.
You can use GR assignment only for confirmation categories that are GR-relevant.
Note
Note that you can only post a goods receipt if a confirmation (e.g. an inbound delivery) has already been entered.
If goods receipt takes place before inbound delivery, you cannot post the goods receipt because the GR cannot then be assigned to an inbound delivery.
Example
Assume you have a PO item covering 100 tons of "Steel 1". You have been notified of two inbound deliveries of 50 tons each. The system will assign each of the subsequent goods receipts to the relevant inbound delivery.
When you post a goods receipt, it is not the total quantity from the PO item (here 100 tons) that appears as the default (suggested) quantity. Instead, the default data will be taken from the inbound deliveries of the item (in this case, the system will provide two default quantities of 50 tons each).
Dependencies
If the batch split realized in the inbound delivery is to be taken into account at the time of goods receipt, you must set the GR assignment indicator for the confirmation category "inbound delivery".
控制作用：
- 不勾選則可以直接參考PO收貨（當然亦可以參考內向交貨收貨），且收貨建議數量是整個PO未清數量；
-
勾選則可以參考內向交貨收貨，亦可以參考PO收貨，但參考PO的前提是必須先創建內向交貨，且如果參考PO收貨，MIGO時會把內向交貨項目建議出來而不是整個PO的未清數量。