Ledger Setup contains the rules relating to the management and processing of standard transactions for each Business Unit, across all ledgers.  The company is able to define the general rules for the ledger, as well as those relating to transactions, rough book accounting and dual base currency accounting. Ledger Setup (LS) allows you to specify rules about how a financials ledger, within a business unit, operates.

For example, you can specify the accounting periods that are open for posting, whether the automatic payments facility is available, determine any automatic sequence numbering requirements.
There are five tab screens used to define these rules:

Let’s now define the rules for our ledger using Ledger Setup - LS

Click here to see the screenshot

This screen is divided into four frames in order to define the Ledger Validity, Provisional Postings, Assets and Allocations. 

Current Period
The current accounting period for the business unit. The current period is often used as the default period in SunSystems. You set the current period here initially. Thereafter, at the end of each period you should use Change Period (CP) to update this period number.

Open Periods From/To
An operator can post journals to any periods in this range. If you leave both fields blank, there are no posting restrictions. You can use relative period numbers, for example +nnn or -nnn, where nnn is the number of periods after or before the current period. You can also enter C, for Current, to allow postings to the current period only, this means to the period specified in the Current Period field.
Open Dates From/To
This controls the only date, or a range of transaction dates, for which operators can post journals. If you leave both fields blank, there are no posting restrictions. You can use relative dates, in the form +nnn and -nnn, where nnn is the number of days after or before the current date. You can also enter T, for Today's date, to allow postings to the current system date only.
Provisional Postings
This setting determines whether or not provisional postings can be made. Provisional postings can be viewed, reported on, and amended before they become permanent ledger postings. Three options are available:

Timing Rule Code
The depreciation timing rule to be used for assets in this ledger.

Exclude Final Value from Calculation
If this option is chosen, by default the final value of an asset is excluded from the depreciation calculations. This can be overridden on particular assets.