每個月的月初，ERP系統就要重新設定現行單據的會計年度及期別，如果現在是2009/10/09要進行物料的轉移，會計年度期別還是2009/09，這時候系統就會不允許輸入十月份的單據。（單據日期必須大於關帳日期，小於等於現行年度期別）
介紹以下三個指令:(Logistics→Materials management→Material Master→Other)
- MMPV : Close Period for Material Master Record
- MMRV : Allow Posting to Previous Perod（也可以用這個來檢視目前的會計期間)
- MMPI : Initialize Period for Material Master Record
MMPV:
這支程式用來設定新的會計期間並且關閉前一個會計期間。會計期間被關閉後就不能變更該期間內的單據 。
MMRV:
設定companycode在會計期間之前的單據也能變更。
MMPI:
Re-open Period closing: 假設有些前期的帳要調整，想重新打開之前的會計期間修正，可使用MMPI處理
如果目前期別是2009/10，要打開2009/07，就要依序打開2009/09, 2009/08,2009/07，修正完資料後，再依序關帳
2009/07→2009/08→2009/09。這個指令對系統的影響性很大不建議經常使用。
提醒：使用MMPI可能造成的問題
Be careful if the period used for initialization precedes the current period in the control record for the company code since this can result in an inconsistency between goods movements and material master segments. This is because the stock information in the material master segments is assigned to the new current period in this case (see the following example).
Example:
Current period 02
Opening stock balance 0 pieces
Goods receipt 10 pieces
Period used for initialization 01
According to the material master segment, there are 10 pieces in stock in period 01, although 10 pieces were posted to stock in period 02 according to the goods movement document.
