General parameters > Chapter Accounting > Parameter GASNEGAMT (Journal entry negative amounts) 

To avoid unexpected results and to be compliant with Portuguese SVAT rules, set this parameter to No to prevent negative amounts in journal entries.

For Portuguese Law, this is not an option and all amounts entered in the general ledger must be positive.

Level of localization/Global variable

This parameter is defined at the level Company.It belongs to Chapter CPT (Accounting) and the Group ACC (Accounting Interface),The following parameters are also associated with this chapter and group :

The global variable GGASNEGAMT is associated with it.