1. P age |1
As an internal procurement activity system performs two functions that are
a) Availability check
b) Transfer of requirements
Availability Check:
As a availability check system carries out availability check for particular material,
particular
order quantity, at particular plant level & calculates ATP quantities by following a formula
i.e.
ATP Qty. = Warehouse Stock + Planed Receipts – Planed Issues
If system finds positive ATP qty. then it confirms the quantities on the requested delivery
date
by following backward scheduling.
If system finds negative ATP qty. then it may confirm the qty after requested delivery date
by
following forward scheduling as well as it transfers the sales order requirements to MRP
(MD04) through transfer of requirements.
Availability check involves two important aspects that are:
1. Checking group of availability check
2. Checking rule
Checking group defines whether system has to carry out availability check or not for the
material. If it has to carry out then for what kind of requirements:
Individual requirements (System immediately transfers the SO requirements to MRP)
Collective requirements ( System transfers the requirements collectively per day / per
week)
Checking rule is determined by two factors that are material type and delivering plant
Checking rule specifies what kind of MRP elements system should include or it should not
include in ATP calculation.
Checking rule is going to be assigned to checking group.
Transfer of requirements:
It involves two important aspects:
a) Requirement class
b) Requirement Type
Requirement class defines whether system has to carry out TOR & Av.Chk. for a transaction
that is going to be determined through requirement type.
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2. P age |2
1 Requirement Class (have)  Many Requirement Types
1 Requirement Type (assigned)  1 Requirement Class
Requirement Class also defines:
 Whether configuration is possible or mandatory for the line item
 Certain costing related data for customer specific requirements
 Also specifies what kind of assembling order type that system has to use for
customer individual requirements
 It also specifies accounting data
As a requirement type it defines what kind of requirement it is i.e. sales order requirement
or delivery requirement or customer specific requirement
Requirement type is going to be assigned to requirement class.
Requirement type is going to be determined by following one search strategy for a
transaction:
1. System first checks strategy group in the MRP fore view of the material master
2. Then it checks the MRP group in the MRP fore view.
3. Checks the material type
4. System assumes a special rule “Item category + MRP type” or in other words the
schedule line category.
5. Checks the item category.
Finally after these 5 checks system declares that the transaction is not relevant for TOR &
availability check functions.
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