Dynamics NAV MRP or MPS
The terms MRP refer to the calculation of the master production schedule and the material requirements based on actual and the forecasted demand. The planning system can calculate either Dynamics NAV MPS (Master Planning Schedule) or Dynamics NAV MRP (Material Requirements Planning) on request, or it can calculate both at the same time.
- Dynamics NAV MPS are the calculation of a master production schedule based on actual demand and the production forecast. The MPS calculation is used for end items that have a forecast or a sales order line. These items are called as the MPS items and are identified dynamically when the calculation starts.
- Dynamics NAV MRP is the calculation of material requirements based on actual demand for components and the production forecast on the component level. Dynamics NAV MRP is calculated only for items that are not MPS items. The purpose of Dynamics NAV MRP is to provide time-phased formal plans, by item, to supply the appropriate item, at the appropriate time, in the appropriate location, in the appropriate quantity.
The planning algorithms used for both Microsoft Dynamics NAV MRP and MPS are identical. The planning algorithms pertain to netting, reuse of existing replenishment orders, and the action messages.
The planning system process examines what is needed or will be needed and what is on-hand or expected. When these quantities are netted against each other, Dynamics NAV MRP provides action messages. Action messages are suggestions to create the new order, change an order, or cancel an order already on order. The term order adds the purchase orders, assembly orders, production orders, and transfer orders.
Links created by the planning engine between demand and it’s related supply can be tracked in the Order Tracking window.
The proper planning results depend on the set up done on an item cards, assembly BOMs, production BOMs, and routings.
Methods for Generating a Plan
- Calculate Regenerative Plan: This function processes or regenerates material plan. This process begins by deleting all the planned supply orders that are currently loaded. All items in the database are re-planned.
- Calculate Net Change Plan: This function processes the net change plan. Items are considered in the net change planning from 2 types of changes:
- Demand/supply changes: These involve the modifications to the quantities on sales orders, production forecasts, assembly orders, production orders, or purchase orders. The unplanned inventory level change is considered as the quantity change.
- Planning parameter changes: These involve the changes in the safety stock, reorder point, routing, bill of material, and changes to the lead time calculation.
- Get Action Messages: This function serves as a short-term planning tool by issuing the action messages to alert the user of any modifications made since the last regenerative or net change plan was calculated.
With each planned method, Dynamics NAV MRP generates worksheet entries assuming infinite capacity. Work center and the machine center capacity is not considered when you develop schedules.
To calculate the planning worksheet
- Enter the Planning Worksheets, and then select the related link.
- Choose the Calculate Regenerative Plan action to open the Calculate Plan window.
- On the Options FastTab, fill in the fields as described in the following table.
Field Description MPS Choose to initiate the calculation of a master production schedule. Items with open sales orders or the production forecasts are considered in this run. MRP Choose to initiate the calculation of material requirements planning. Items with the dependent requirements are considered in this run. Typically, Dynamics NAV MRP and MPS are run at the same time. To run MPS and Dynamics Navision MRP at the same time, the Combined MPS/MRP Calculation field must be selected on the Planning FastTab in the Manufacturing Setup window. Starting Date This date is used to evaluate the inventory availability. If the item’s on-hand quantity is below the reorder point, the system forward-schedules the replenishment order from this date. If an item is below its safety stock, the system back-schedules a replenishment order due on the planning starting date. Ending Date This is a ending date of the planning horizon. Neither demand nor the supply is considered after this date. If the reorder cycle for the item extends beyond the ending date, the effective planning horizon for that the item is equal to the order date + reorder cycle.
The planning horizon is a time that plan is extended to. If the horizon is Very small, the items with a longer lead time are not ordered on time. If the horizon is very long, too much time is spent in reviewing and processing the information that likely changes before it is needed. It is possible to set 1 planning horizon for the production and a longer one for purchases, although it is not required. The planning horizon for the purchases and production should be set to cover the cumulative lead time for components.
Stop and Show First Error Choose if you want the planning run to stop as soon as it encounters the error. At the same time, the message is displayed with data about the first error. If the error exists, only the successful planning lines made before the error was encountered will be presented in planning worksheet. If you do not select this field, the Calculate Plan batch job will continue until it has completed, that is, errors will not interrupt the batch job. If one or more errors exist, the message will show after completion with information about how many items are affected. The Planning Error Log window will then open to provide more details about the error and links to the affected item cards. Use Forecast Choose the forecast that should be added as demand when you run the planning batch job. The default forecast is set up on a Planning FastTab in Manufacturing Setup window. Exclude Forecast Before Define how much of the chosen forecast to add in the planning run by entering the date before which forecast demand is not included, thus allowing you to exclude old information. Respect Planning Parameters for Exception Warnings By default, this field is selected.
Supply on the planning lines with warnings is normally not modified according to planning parameters. Instead, the planning system suggests the supply to cover the exact demand quantity. However, you can define the certain planning parameters for planning lines to be respected with the certain warnings.
- On the Item, FastTab, set filters to run the planning based on the item, item description, or location.
- Choose the OK button. The batch job runs and the planning worksheet is populated with the planning lines.
To perform action messages
- In the Planning Worksheet window, select the Carry Out Action Message action.
- On the Options FastTab, specify how to create the supplies. Fill the fields as described in the below table.
Field Description Production Order Mention how you want to create the production orders. You can do this directly from planning line proposals. You can make either the planned or firm planned production orders. Assembly Order Mention how you want to create the assembly orders. You can do this directly from planning line proposals. Purchase Order Specify how you want to create purchase orders. You can do this directly from planning line proposals.
If you select to copy the planning line proposals for purchase orders to the requisition worksheet, Choose the template and worksheet name.
Transfer Order Specify how you want to create transfer orders. You can do this directly from planning line proposals.
If you Select to copy the planning line proposals for transfer orders to the requisition worksheet, choose the template and worksheet name.
Combine Transfer Orders Choose if you want to combine transfer orders. Stop and Show First Error Choose if you want the Carry Out Action Msg. – Plan. batch job to stop as soon as it encounters the error. At the same time, the message is shown with data about the first error. If the error exists, the planning lines processed before an error was encountered will create supply orders.
- On the Planning Line FastTab, you can set filters to limit the perform action messages.
- Choose the OK button.
The batch job deletes the lines in a planning worksheet after it has performed the action message. The other lines remain in a planning worksheet until they are either accepted at a later date or else deleted. You can also delete the lines manually.
Action messages are issued by the order tracking system when the balance is unattainable in the existing order network. They can be seen as the suggestion for you to process changes that reestablish the equilibrium between supply and demand.
The generation of the action messages occurs one level at a time, for each item’s low-level code. This makes sure all the items that experience or will experience changes in the supply or demand are considered.
To avoid small, superfluous, or unimportant action messages, the user can establish dampeners, which serve to restrict the generation of action messages to only those changes that exceed the defined quantity or number of days.
After you have reviewed the action messages and determined whether to accept all of the suggested changes, select the Accept Action Message field, and then you are ready to update the schedules accordingly.
In response to any supply/demand imbalances, the below action messages are generated.
|New||If demand cannot be fulfilled by suggesting action messages to Change Qty., Reschedule, or Reschedule & Change Qty. On existing orders, the action message New is generated, which suggests the new order. In addition, message New is generated if there are no existing supply orders in a reorder cycle of the item in question. This parameter determines the number of periods forward and backward in the availability profile when it searches for the order to reschedule.|
|Change Quantity||When demand that is tracked to a supply order experiences a quantity change, the action message Change Qty. Is generated, which indicates the related supply should be changed relative to the change in demand. If a new demand emerges, Dynamics NAV MRP searches for the nearest existing unreserved supply order in the reorder cycle and issues a change of action message for that order.|
|Reschedule||When a supply or demand order experiences a date modification causing an imbalance in the ordered network, the action message Reschedule is generated. If there is a one-to-one relationship between demand and supply, an action message is generated suggesting that the supply order is moved accordingly. If the supply-order covers the demand from more than one sales order, the supply order is re-scheduled equal to the date of the 1st demand.|
|Resch. & Chg. Qty.||If both the dates and the quantities of the order have been modified, you must change the plans with regard to both circumstances. Action messaging gathers both actions in one message, Reached. and Chg. Qty., to ensure that the ordered network returns to balance.|
|Cancel||If the demand, which has been covered on the order-to-order basis, is deleted, the action message is generated to cancel the related supply order. If the relationship is not order to order, the action message is generated to change it and in order to reduce the supply. If through other factors, such as the inventory adjustments, the supply order is not required at the time the action messages are generated by a user, the Dynamics NAV suggests the action message of Cancel in the worksheet.|