ATP Basics (可用性检查基础)
This note covers the Available-to-Promise (ATP) logic and availability checking in SD.
What is Availability Check?
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| Availability Check = Checking if requested material is available on requested date
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Availability check answers: Can we deliver the customer’s order on time?
ATP Logic (ATP逻辑)
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| ATP Quantity = Warehouse Stock + Planned Receipts - Planned Issues
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ATP Components
| Component |
Description |
Examples |
| Warehouse Stock |
Physical stock in plant/storage location |
Unrestricted-use stock |
| Planned Receipts |
Incoming stock movements |
Purchase orders, Production orders, Inbound deliveries |
| Planned Issues |
Outgoing stock movements |
Sales orders, Deliveries, Requisitions |
ATP Calculation Example
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| Initial Situation:
Warehouse Stock: 100 units
Purchase Orders (incoming): 50 units
Sales Orders (outgoing): 30 units
ATP Calculation:
ATP = 100 + 50 - 30 = 120 units available
New Order: Customer requests 40 units
Check: 40 ≤ 120? YES
Result: Order can be confirmed
Updated ATP:
ATP = 100 + 50 - (30 + 40) = 80 units
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Checking Group vs Checking Rule (检查组 vs 检查规则)
Checking Group (检查组)
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| Checking Group = Material-specific availability check settings
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| Attribute |
Description |
| Scope |
Material-specific (defined in material master) |
| Control |
How availability check is performed for this material |
| Examples - Daily check, Weekly check, Individual requirements |
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- Checking group is assigned to material master (sales view)
- Multiple materials can share same checking group
- Controls inclusion of stock and receipts
Checking Rule (检查规则)
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| Checking Rule = Transaction-specific availability check settings
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| Attribute |
Description |
| Scope |
Transaction-specific (defined in sales order type, delivery type) |
| Control |
How availability check is performed for this transaction |
| Examples - Sales order check, Delivery check, RP check |
|
- Checking rule is assigned to sales order type, delivery type
- Different rules for different business processes
- Controls scope of check (what to include/exclude)
Combination Effect
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| Checking Group (Material) + Checking Rule (Transaction) = Complete Check
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| Combination |
Result |
| Material A + Sales Order Check |
ATP check for order of Material A |
| Material A + Delivery Check |
ATP check for delivery of Material A |
| Material B + Sales Order Check |
ATP check for order of Material B |
Availability Check Procedure (可用性检查流程)
Check Sequence
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| ┌─────────────────────────────────────────────────────────┐
│ AVAILABILITY CHECK SEQUENCE │
├─────────────────────────────────────────────────────────┤
│ 1. Enter sales order item │
│ ↓ │
│ 2. System reads checking group (from material master) │
│ + checking rule (from order type) │
│ ↓ │
│ 3. Calculate ATP quantity │
│ ├─ Include: Warehouse stock │
│ ├─ Include: Planned receipts (POs, PROs) │
│ └─ Include: Planned issues (other orders) │
│ ↓ │
│ 4. Compare requested quantity vs. ATP quantity │
│ ↓ │
│ 5. If sufficient: Confirm full quantity │
│ If insufficient: │
│ ├─ Partial delivery: Confirm available quantity │
│ ├─ Backorder: Confirm later date │
│ └─ No confirmation: Reject order │
│ ↓ │
│ 6. Update ATP quantity │
│ ├─ Reduce ATP by confirmed quantity │
│ └─ Reserve stock for this order │
└─────────────────────────────────────────────────────────┘
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Confirmation Categories (确认类别)
Confirmation Types
| Type |
Code |
Description |
| Full Confirmation |
- |
Full quantity on requested date |
| Partial Confirmation |
- |
Partial quantity on requested date, remainder later |
| Backorder |
- |
Full quantity on later date |
| No Confirmation |
- |
Cannot confirm (customer decision) |
Schedule Line Categories (计划行类别)
| Category |
Description |
Usage |
| CP |
No availability check |
No ATP check performed |
| CN |
Not relevant |
Not relevant for ATP |
| CT |
Delivery selection |
Individual delivery selection |
| CS |
Goods issue |
No ATP check |
Special Business Scenarios (特殊业务场景)
Make-to-Order (按订单生产)
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| Make-to-Order = Product produced specifically for customer order
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| Attribute |
Description |
| Strategy |
Individual requirements (strategy 20) |
| ATP Scope |
Check only for this order (no shared stock) |
| Linkage |
Sales order linked to production order |
| Inventory |
No general stock, only order-specific stock |
Make-to-Stock (按库存生产)
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| Make-to-Stock = Product produced for general stock
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| Attribute |
Description |
| Strategy |
Planned independent requirements (strategy 10) |
| ATP Scope |
Check against general stock |
| Linkage |
Sales order not linked to production |
| Inventory |
General stock shared by all orders |
Rush Orders (紧急订单)
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| Rush Order = Immediate delivery required
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| Attribute |
Description |
| Procedure |
Check current stock, ignore future receipts |
| Logic |
ATP = Warehouse stock - Planned issues |
| Result |
Confirms only what’s currently available |
ATP in Delivery (交货时的可用性检查)
Delivery ATP Check
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| Delivery ATP = Final confirmation before goods issue
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| Difference from Order Check |
Description |
| Timing |
At delivery creation (not order entry) |
| Scope |
More accurate (other orders may have been created) |
| Result |
Can change order confirmation |
| Action |
May create picking, shipping documents |
Stages
| Stage |
Check |
Action |
| Order Entry |
Preliminary check |
Tentative confirmation |
| Delivery Creation |
Final check |
Definitive confirmation |
| Picking |
Physical check |
Verify physical availability |
| Goods Issue |
Stock posting |
Inventory reduction |
Rescheduling (重新计划)
What is Rescheduling?
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| Rescheduling = Moving delivery dates based on availability changes
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Rescheduling Process
| Step |
Description |
| 1. ATP situation changes (new receipts, issues) |
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| 2. System runs rescheduling program |
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| 3. Proposes new dates based on ATP |
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| 4. User accepts/rejects proposals |
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Customizing Availability Check (定制可用性检查)
Key Settings
| Setting |
Description |
Location |
| Define Checking Groups |
Material-specific check settings |
IMG → SD → Basic Functions → Availability Check |
| Define Checking Rules |
Transaction-specific check settings |
IMG → SD → Basic Functions → Availability Check |
| Define Scope of Check |
What to include in ATP calculation |
IMG → SD → Basic Functions → Availability Check |
| Define Procedure |
Confirmation logic |
IMG → SD → Basic Functions → Availability Check |
Summary Diagram
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| ┌─────────────────────────────────────────────────────────┐
│ ATP CALCULATION │
├─────────────────────────────────────────────────────────┤
│ │
│ ATP = Warehouse Stock + Planned Receipts - Planned Issues
│ │
│ ┌──────────────┐ ┌──────────────┐ ┌─────────────┐│
│ │ Warehouse │ │ Planned │ │ Planned ││
│ │ Stock │ │ Receipts │ │ Issues ││
│ ├──────────────┤ ├──────────────┤ ├─────────────┤│
│ │ - Unrestricted│ │ - POs │ │ - Orders ││
│ │ - Quality │ │ - PROs │ │ - Deliveries││
│ │ - Consignment│ │ - Inbound │ │ - Requisitions│
│ └──────────────┘ └──────────────┘ └─────────────┘│
│ │ │ │ │
│ └────────────────────┴────────────────────┘ │
│ │ │
│ ▼ │
│ ┌───────────────┐ │
│ │ ATP Quantity │ │
│ └───────────────┘ │
│ │ │
│ ▼ │
│ ┌──────────────────────────────┐ │
│ │ Compare: Requested vs ATP │ │
│ └──────────────────────────────┘ │
│ │ │
│ ┌─────────┴─────────┐ │
│ ▼ ▼ │
│ ┌──────────────┐ ┌──────────────┐ │
│ │ Sufficient │ │ Insufficient │ │
│ │ → Confirm │ │ → Partial/ │ │
│ │ Full Qty │ │ Backorder │ │
│ └──────────────┘ └──────────────┘ │
│ │
└─────────────────────────────────────────────────────────┘
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- [[05-Availability-Check/Business-Scenarios]] → Sample business scenarios
- [[05-Availability-Check/Transportation]] → Transportation processing
- [[05-Availability-Check/Practice-08-09-Availability]] → Practice exercises
- [[06-Make-to-Order/Presales-Processing]] → Make-to-order processing
- [[05-Availability-Check/Practice-08-09-Availability]]