Problem in the MRP Run and Frequency

Our central warehouse runs the MRP for the planning plant and uses special procurement key in the material master MRP2 view for the planning plant, so that the STPO are generated for different production plants. But purchase requisitions are also being generated when MRP is run at the planning plant.

Our requirement is that purchase requisitions should not be generated when the MRP is run at the planning plant. purchase requisitions should be generated when MRP is run again at the production plant. Please note that BOM are maintained in the production plant material master only.

I believe that you are maintaining PIR at planning plant where MRP is run. Please note the following basic MRP principle and logic.

1. MRP performs net requirements calculation based on forecast, available inventory and scheduled reciepts and scheduled issues out of the plant.

2. Then it applies the lot sizing procedure to calculate the order quantites and creates scheduled receipts (requisitions or planned orders) in the planning plant.

3. It creates planned orders for the lotsized quantity and determines the order dates via scheduling strategy selected during the run initiation.

4. Explodes the BOM for each planning proposal it created and repeats step 1 to 4 for each component.

Please note that the MRP logic always starts with L-L code 000 and works progressively increasing code levels.

Based on the logic explained, MRP will mandatory create planning proposals at planning plant (STTR in case of Stock Transports) in order to fulfill the step 3 and plan the production plants using logic in step 4.

The SPK will only allow you to procure from one production plant. Whereas if there are multiple production plants supplying to your planning plant, you have to consider using MEQ1 as suggested:

Try giving quota arrangement in MEQ1 , specify the spl procurment key there "p" or "u" specify qty 100% & give the production plant there. Maintain quota arrangement key 03 in mrp 2 screen.

Muthu P. Chinnadurai.

How frequently we should run MRP i.e daily weekly or fortnightly?

The frequency of MRP run depends on the business scenario. How complex the system is, how fast you would like to respond to changes. What is your planning strategy (MTO/MTS)?

In most cases, the MRP is run in background every night or can be run evevery 12 hours. It again depends on the business scenario. If it is pure MTS with very little variation...then you can run MRP twice a week. But if you are using pure MTO with lot of variation and you would like to respond immediately to client's requirement, then you will run the MRP daily or more frequently.

To answer this question, the sap consultant would have to know what planning strategy the company is using.
- How frequently does the data change?
- How huge the client data?
- How quickly the client would like to respond to you customers? etc..