# Infor LN Master Planning: How It Works and a Setup and Run Checklist > Source: https://netray.co/erp-help/infor-ln-master-planning-setup-run-checklist > Publisher: Netray (netray.co), AI and integration engineering for ERP and manufacturing systems. > Section: ERP Help ## Short answer Master planning in Infor LN looks at demand (sales orders, forecasts, dependent demand), nets it against inventory and open supply within the planning horizon, and generates planned orders with pegging that links each supply to the demand it serves. The result is only as good as the item planning data, the plan unit, the calendars and the horizon settings, so the checklist below starts with data, not the run. ## Kind how-to ## System infor-ln ## Erp Infor LN ## Module Enterprise Planning / Master Planning ## Query infor ln master planning ## Alternate Queries - infor ln planner plus - infor ln planned orders pegging planning horizon - how does master planning work in infor ln ## Applies To Infor LN 10.x Enterprise Planning; the plan unit based planning model; session names vary by feature pack ## Steps ### Setup and run checklist **Items:** - Define the planning structure: the plan units, the items in each plan unit, and the plan item versus non-plan item split so the plan covers the right level. - Maintain item planning data: order policy, lead times, lot sizing, safety stock, and whether the item is planned or purchased by the planning engine. - Check the calendars and the enterprise unit so working days and lead times resolve correctly. - Set the planning horizon, time fences and period definitions for the plan, short enough to stay reliable and long enough to cover the longest lead time. - Make sure demand is clean: approve the sales orders and forecasts you want in the plan, and remove stale or duplicate demand. - Run the planning (generate planned orders) for the plan unit or a selected item range, first for a small range to inspect results. - Review the planned orders, the pegging and the messages (reschedule in, reschedule out, cancel) in the planner workbench. - Release or transfer the firm planned orders to the shop floor, purchasing or warehousing, and re-run to confirm the plan nets to zero exceptions. ## Sections ### How the planning engine reasons **Body:** For each planned item, the engine builds time buckets across the horizon and nets gross requirements against on-hand stock, open orders and planned supply. When net requirement is negative at a bucket, it creates a planned order sized by the order policy and offset by the lead time. Component requirements for those planned orders become dependent demand for the next level down, and the same logic repeats. Pegging records which supply serves which demand. It is what lets a planner answer the question which sales order caused this planned purchase, and it is what the project cost pegging uses downstream. If pegging looks wrong, the cause is nearly always demand that should not be in the plan or supply that is not allocated the way you expect. ### Planning horizons and time fences **Body:** The planning horizon is how far ahead the plan looks. Inside the frozen portion of the horizon, the engine should not reschedule existing orders on its own, and the exceptions it raises are suggestions for the planner. Beyond it, the plan is free to move. A horizon shorter than the cumulative lead time of the longest item means long-lead purchased parts are never planned in time. Typical misconfigurations: a horizon covering the order book but not the supplier lead time, safety stock set at several levels of a BOM and double counted, and lot sizes that were copied from a different item type. Review these before blaming the engine. ### Diagnosing a plan that looks wrong **Body:** Work from one item. Check its planning data, then its demand, then its supply, then the resulting planned orders. Most surprising plans come from one of these: the item is not flagged as planned, demand is not approved or is dated outside the horizon, or an open supply order is dated later than the demand and the engine suggests rescheduling it. If planned orders are not generated at all, see the dedicated page on Enterprise Planning not generating planned orders. If the plan is generated but too slow, review the size of the range, the number of plan items and the database load during the run, and run the planning in off-peak windows. ## Pitfalls - Running the plan for all items before verifying a small range. - A horizon shorter than the longest cumulative lead time. - Stale forecasts and unapproved orders feeding the plan. - Safety stock maintained at several BOM levels, inflating requirements. - Releasing planned orders without reviewing pegging and messages. ## Ai Angle Planners spend most of their time answering why for individual items. An assistant grounded in LN planning data can show for one item the demand, supply, order policy and the resulting planned orders in plain language. ERPray runs these read-only on-prem; releasing orders stays with the planner. ## Faq ### What is master planning in Infor LN? **Answer:** It is the planning process that nets demand against stock and open supply across a horizon and generates planned orders, with pegging to show which demand each supply serves. It is part of LN Enterprise Planning. ### What is Infor LN Planner Plus? **Answer:** Names for planning tools around LN have changed over the years. Confirm with your Infor partner which planning product and version you license; the core Enterprise Planning behavior described here is the standard LN module. ### Why are no planned orders generated? **Answer:** Usually the item is not set up as a planned item, demand is outside the horizon or unapproved, or supply already covers it. See the page on planned orders not generated for a full list of checks. ### How long should the planning horizon be? **Answer:** At least as long as the longest cumulative lead time of the items you plan, plus a margin. A shorter horizon means long-lead parts are not seen early enough to order on time. ## Search terms infor ln master planning, infor ln planner plus, infor ln enterprise planning, infor ln planned orders, infor ln pegging, infor ln planning horizon, infor ln mrp, infor ln plan unit --- Talk to an engineer: https://netray.co/contact?intent=erp_ai | Machine catalog: https://netray.co/agent/catalog.json