Explain how to define val. class for NLAG material type?

To make this clear for everyone who seems to have problems understanding the concept of NLAG materials:

1. NLAG means non-stock. 
This means that when you do goods receipt of these items, they are posted directly to consumption. 
Non-stock material is material that is not held in stock because it is consumed immediately. 
(Office supplies such as stationary. You need to create purchase order and accounting document for payment but the stock balance is always zero as it is issued out immediately to the various department.) 

2. Since there materials are posted to consumption, there is NEVER any updating of any stock quantities or stock values.

3. Since the valuation class is used to determine which STOCK account is to be posted to, there is NEVER a valuation class for non-stock materials. 
If you system ask you for this, it is set up incorrectly.

4. In the customising of the material type NLAG, neither quantity updating or stock updating should be ticked.

5. In the customising of the material type, the accounting view MUST NOT be ticked.

6. When you create a P.O. you will have to enter an account assignment category.

7. In  account determination the system will use GBB. In this case, GBB is configured usually to use the account modification as an influencing factor. The account modification used is found in the customising of the account assignment you use in the purchase order.

8. Try it.  It works.
 

NLAG Material type field selection  

I have material type (NLAG), which is having only view (Basic data1, Basic data2, Foreign Trade Import data and Purchase order text) available. But during creation of material master as a industry sector(M) and Material type: NLAG, system asked me to enter Profit center as a mandatory field.
I would like to know, Profit Center field is coming from where and how do I make it as a non-mandatory field for a particular material type(NLAG) only.

Follow following steps:
1. Go to Material master creation - Profit center field
2. Press F1 & see technical details for field name,
3. Go in spro - IMG - Log General - Material master - field selection- Assign Fields to Field Selection Groups - put a field name in field name tab at bottom after clicking tab - It will show you selection group - Click the arrow near selection group number - 
then choose your field reference NLAG & click optional radio button. & save.

Also:

Go to OMSR transaction, enter the filed name MARC-PRCTR there, it will show the field selection group assigned to it say for e.g.; 27 is assigned to the filed Marc-Prctr.

Now go to OMS9 trx, give the filed status group as 27 and against the material type nlag, you make it in to OPTIONAL one.

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