APS Overview

Advanced Planning and Scheduling (APS) generates real-time projections of when you can complete orders by comparing all demands (such as customer orders) against a long-term plan. The system views the current status of inventory levels, forecasts, job schedules, PO due dates, customer orders, etc. and creates planned orders accordingly to satisfy the demands. You then "firm" the planned orders into purchase orders, purchase requisitions, job orders, production schedules, or transfer orders.

The long-term plan includes information such as:

Demand orders that consume inventory and resource capacity
Supply orders that add to inventory
Each operation in the plan
Each item in the plan
The projected completion date for every planned order
Each resource allocated to a job
Scheduled operations (for work orders in which the resource usage is frozen)
Every lateness cause for every demand in the plan

Infinite APS vs. APS

You can run Advanced Planning and Scheduling in Infinite APS Mode or APS Mode. The difference between these modes of planning is in the resource capacity the system considers when generating a plan. Infinite APS assumes infinite resource capacity, while APS constrains the plan realistically based on availability of resources.

APS mode considers whether the crew and machines are on-shift and not busy working on another demand. In APS, resources are capable of working on a limited number of tasks while on shift. In APS mode, the Get CTP button is available on various forms such as Customer Order Lines and Job Orders.
Infinite APS mode uses the sum of the Move, Queue, Setup, Run, and Finish times defined for the operations and assumes the resources are capable of working on an unlimited number of tasks while on shift. In Infinite APS mode, the Get ATP button is available rather than the Get CTP button.

See Resource Planning Examples for an illustration of how Infinite APS and APS plan resources for the same order data.

See About the APS Planning Process for a detailed discussion of how the APS algorithm plans demands into available supplies, on-hand inventory, and resource capacity.

Note: If the APS module is unlicensed, APS Planning can only be run in Infinite mode.

MRP vs. APS

Material Requirements Planning (MRP) plans requirements for items according to the level the item appears in a BOM, batching together requirements needed at the same period of time. Like APS, MRP generates planned orders, which you firm into actual SyteLine transactions.

MRP and APS use the same basic input data. However, the APS system plans all requirements for one demand (through the end item's entire BOM), then plans all requirements for the next demand, and so forth for all the demands, based on order priority and each demand's due date.

Examples of APS differences from MRP are as follows:

APS "pull-plans" each demand backward in time, starting from the due date, to determine the start dates for the planned orders. If any single component from the demand cannot be pull planned within the time between the due date and the current date, the system "push-plans" the entire demand forward in time, starting from the current date, out to an as-soon-as-possible date. APS never plans into the past (unlike MRP, which allows start dates in the past).
APS does not automatically combine planned orders for items that are needed within the same period of time. You can set the Planned Orders Consolidation options on the APS tab of the Planning Parameters form if you want planned orders to be combined, such as for a "days supply."
See Consolidating Planned Orders for more information.
APS does not always recommend moving a job to an earlier date to satisfy a demand. Instead, it creates a new planned order due earlier than the existing firmed job. However, if the supply is available within the Supply Usage Tolerance, the system will use the supply when the demand needs it. This behavior is appropriate in a finite capacity environment because you may be able to feasibly fit in a small job for a small order in situations where a larger job could not be moved.

Setup Steps and Daily Procedures

See the Installation Guide for installation and setup procedures related to APS.
See APS Steps for the general business process and related procedures.

Methods of Planning

You run APS in the following situations:

APS Planning form: When you initially set up the system, and then on a scheduled basis (such as nightly), you run APS Planning to synchronize all demands with the latest inventory, supply, shifts, and resources information. You can run APS Planning for a single site or globally across all sites defined on the APS Sites and Alternative Management form. You can also set up the system to replicate demand transfer orders to your supply sites.
The system deletes all existing plan information and regenerates it using the latest data. In most situations, you will run APS Planning for a long horizon, such as one or two months. (If you are using Scheduling, you will likely run the Scheduler with a shorter horizon, such as one or two days.) The APS Planning activity creates planned orders and exception messages.
Incremental planning: When you save certain types of transactions (such as customer orders and job orders), and the Plan on Save field is selected on the transaction, SyteLine inserts the new demand into the existing APS plan. The demand is planned using the inventory, supplies, and capacity that were not allocated to other demands during the last run of APS Planning or by demands that were previously incrementally planned.
Get ATP/CTP: For certain transaction types, the system can insert a single demand/line item into a temporary "test" copy of the plan to determine feasibility. In Infinite APS mode, the resulting availability date is referred to as the available-to-promise (ATP) date. In APS mode, it is the capable-to-promise (CTP) date. The ATP/CTP process returns a projected availability date for the demand; if the date is acceptable, you can allow the system to insert the demand incrementally into the actual plan.

Planned Orders and Interaction with the Scheduler

When you run APS Planning, the system creates planned orders for demands that were not satisfied by on-hand inventory and planned supplies. On the Shop Floor Control Parameters form, you can specify that the Scheduler consider these planned orders as demands that must allocate resources (thus creating a more realistic scheduling simulation).

After you firm the planned order into a job, purchase order, etc., you can run APS Planning again to plan the new demand (using its routing/BOM). When you then run the Scheduler, the operation start and end dates are based on the dates APS calculated for the original planned order (the operation start and end dates may change depending on the rules set up for the Scheduler). Subsequent runs of APS Planning will treat those scheduled operations as "frozen," and will not move the operation start and end dates. However, subsequent runs of the Scheduler may move the operation start and end dates again based on the latest information.