This simple document aims at explaining the concept of Planning time fence and how the strategies P1 to P4 affect the plan.
What is Planning Time Fence: Planning time fence (PTF) is a period which we define in number of days in the MRP1 view of material master
It is a period which we can set so that the consequent MRP runs do not affect the plan which falls within the PTF
In the above screen shot we have set the PTF as 5 days, this will be calculated and set for the next 5 days, so once a planned order falls within
this period it will be firmed (based on the MRP type) and hence be protected from any automatic changes based on the MRP runs.
Working with MRP types
MRP type P1: With MRP type P1, system will consider the requirements which fall within the PTF and creates new requirements to cover the shortages
within the PTF, but the procurement proposals will be created outside teh PTF
Once these procurement proposals come within the PTF, they will be firmed automatically
In the above example, we can observe in the ‘stock requirements list’ that there was an available stock of 10 and a PIR was created for 20 units
well within the PTF, once we execute MRP, system has created a planned order to cover the shortage outside of the PTF.
With MRP type P1, the planned orders coming within the PTF will be firmed automatically (as in the below example)
Now, if there is a change in teh requirement which falls within the PTF, system will not make changes for the planned orders which falls within the PTF, only the
planned orders or procurement proposals falling outside the PTF will be adjusted
In the above example we can observe that the PIR was changed from 20 to 15, but there is no change in the planned order which comes inside the PTF
MRP type P2: With MRP type P2, system will not consider the PIR’s falling within the PTF, planned orders or procurement proposals will be created only
for the requirements which falls outside the PTF. Hence with type P2 there will not be any planned orders created to cover shortages within the PTF.
Planned orders coming within the PTF will be firmed, hence protecting it from changes in the consequent MRP runs
Here in the above example we can observe that, there was no requirement created by the system to cover the PIR, which falls within the PTF
Now if there is a PIR which falls outside teh PTF, system will consider this requirement and create planned orders to cover this requirement
MRP type P3: With type P3 system will consider the requirements which falls within the PTF and creates planned orders outside of the PTF.
Requirements which falls outside the PTF are also consider in the requirements planning.
Though this MRP type looks similar to P1, the difference between the two is that with type P3, planned orders coming within the PTF are not firmed
automatically by the system.
MRP Type P4: With type P4, no new planned orders are created to cover the requirements which falls within the PTF, system considers the
requirements which falls oustide the PTF.
Now the diference between P2 and P4 is that in P2, all the planned orders coming within teh PTF are firmed, whereas in P4, there is no automatic
firming for requirements coming within the PTF
The logic will be the same for M1 to M4 MRP types