Planning (MRP)
How demand turns into suggested jobs and purchase orders — and where that ends and scheduling begins.
Planning determines what to make or buy and in what quantity. Carbon's nets demand against supply across the complete . It converts shortages into suggested orders and offsets component demand by .
Two stages
Planning has two distinct stages:
- MRP, explode and net. The engine explodes demand through bills of material, nets it against on-hand plus open jobs and purchase orders, and writes period-bucketed demand forecasts (plus the demand and supply actuals it read). It then sizes each shortage with the item's and writes a for it, and one for every open order whose date or quantity no longer fits.
- Planning views, show and apply. The production and purchasing planning pages project running stock week by week, show the actions on each row, and let you apply them.
MRP suggests, it never auto-orders. The engine writes forecasts and suggestions; turning a suggestion into a real job or PO, or moving an existing one, is an explicit action you take on the planning page.
When it runs
MRP recalculates on its own every 3 hours. To run it once a day instead, go to Settings → Planning → MRP Schedule, choose Once a day, and pick the hour; the hour is on your company's time zone. You can also run it yourself at any moment with Recalculate on the planning pages, whichever schedule is set; hover the button to see which schedule is active.
What feeds it
| Input | Source |
|---|---|
| Customer demand | Open sales-order lines, by promised date. |
| Production demand | Job material still to issue, offset by lead time. |
| Forecast demand | Manually entered demand projections. |
| Open supply | Open jobs and open purchase-order lines. |
| On hand | The item ledger balance, without rejected lots and without stock in storage units. |
Reorder policy
Each item, per location, carries a reordering policy that decides how a suggestion is sized: Manual Reorder (suggests nothing), Demand-Based Reorder (the default), Fixed Reorder Quantity, or Maximum Quantity. Each is tuned by reorder point, order quantity, accumulation period, and min/max/multiple rounding. See Reordering for the parameters in full.
From suggestion to order
An item's determines where its shortage appears. Make items produce suggested on the production planning page; Buy items produce suggested POs on the purchasing page. Choosing Order creates a saved job or purchase order with status "Planned", pending release into its normal lifecycle. Purchase orders are grouped one per supplier per week, so each week's order is sent on its own and the later weeks stay open to planning changes.
"Planned" is a real, saved job or PO that came from a planning suggestion and is waiting to be released — distinct from a hand-started "Draft".
Reading the grid
Each row is an item at the location. Stock Availability draws the projected stock for every planning week as one strip; the CSV export keeps a column per week. Weeks are numbered from today ("Present Week", "Week 2", …); to number them by calendar week of the year instead ("Week 44", "Week 45", …), turn on Settings → Planning → Calendar Weeks. That setting also numbers the weeks in Demand Forecasts. 1st Negative On Hand is the first week the projection goes below zero. Latest Order Date is the date you must order by to receive in time (the required date less the lead time); it turns red once it has passed. Open a row to see the order drawer.
Planning actions
Every MRP run leaves a worklist on the planning pages. Each row's Actions column shows one chip per open action type, an ASAP flag when a suggestion is already late, and a muted count of the actions you dismissed. Expand the row to see each action with its target order, quantity, date and assignee; hover the action type for MRP's reason.
| Action | Target | What applying it does |
|---|---|---|
| Order / Make | none yet | Opens the order drawer; the existing Order button creates the PO or job. |
| Expedite / Defer | an open PO line or job | Moves the required date (PO line) or the due date (job) to the suggested date. |
| Increase / Decrease | an open PO line or job | Sets the line's purchase quantity, or the job's quantity, to the suggested quantity. |
| Cancel | an open PO line or job | Deletes the PO line, or cancels the job, when nothing needs it. |
Apply is offered only while the target can still change from planning: a PO at "Draft" or "Planned", a job at "Draft" or "Planned". A PO that has been sent or is in approval, a job on the floor, or a PO line whose date the supplier has promised shows Review instead, and you make the change on the order itself. Select several rows and choose Apply Suggested Changes to apply every open action on them at once. Apply writes the suggestion as it is at that moment: if an MRP run refreshed the action after the page loaded, the refreshed quantity or date is what lands. A job that had no deadline gets a Soft Deadline with its new date. Cancelling a PO line deletes it, so it needs the purchasing delete permission.
A dismissed action stays dismissed until the need changes
Dismiss hides an action you have decided not to take. The next MRP runs keep it hidden while the suggested quantity stays the same and the date moves by no more than the reschedule tolerance; a larger change reopens it. Reopen brings it back by hand. Assign to Me sets the owner, and MRP keeps a hand-set owner on later runs.
An applied action is finished: the next run re-evaluates the changed order and writes a fresh action only if something still does not fit.
The order drawer
The drawer shows the item's suggested orders — the same Order or Make suggestions as the row's action list, one per week, refreshed each time MRP runs — and, below them, its Open Jobs (production) or Open Orders (purchasing). An open order at "Draft" or "Planned" can be edited in place: change its Due Date or Quantity in the grid and the order is saved. The Suggestion column shows the open action on that order, with the same Apply, Dismiss, Reopen and Assign controls as the grid. Suggested orders due after the row's planning horizon stay out of the drawer until you choose N More After <date>. The chart in the drawer marks the planning horizon.
Planning horizon
The Planning Horizon column is a date per row: today plus the item's horizon in days. A row shows only the actions and suggested orders due on or before that date, so a long planning window does not bury next week's work. Set the company default in Settings → Planning → Planning Horizon, and override it per item on the item's planning tab (Planning Horizon (Days)). An item set to 0 shows everything MRP plans, whatever the company default.
Moving the date in the column widens or narrows that one row for this page view only; it never changes the item.
Reschedule tolerance
MRP suggests Expedite or Defer only when an open order lands more than the tolerance away from the date it is needed. The default is 7 days. Set it in Settings → Planning → Reschedule Tolerance; 0 suggests a move for any date difference.
Two kinds of open order never get a change suggestion. An order due after the planning window (48 weeks) is outside what the check can judge, so it is left alone rather than offered for Cancel. An order that holds the item's safety stock or reorder point is never Cancelled, Decreased or Deferred; it can still be Expedited when demand needs it earlier.
Planning ownership
Each action gets a , resolved from the most specific setting that names one: the item at that location, then the item group at that location, then the location, then the company default. Set the rungs in Settings → Planning → Planning Ownership and on the item's planning tab (Responsible Employee). Filter the grid by assignee to see your own worklist.
Planning vs scheduling
Planning determines quantities; scheduling determines timing and work-center allocation. After a job exists, scheduling places its on and calculates dates without changing quantities.
Related
The replenishment policies and parameters that size a suggestion.
What a Make suggestion becomes once you order it.
The projections MRP plans against, and how real orders consume them.
The planning settings behind the horizon, the tolerance and the owner ladder.