Every input field read in binary format is assigned a field length (number of digits) by the compiler. A length of 4 is assigned to a 2-byte binary field; a length of 9 is assigned to a 4-byte binary field, if the field is not defined elsewhere in the program. Because of these length restrictions, the highest decimal value that can be assigned to a 2-byte binary field is 9999 and the highest decimal value that can be assigned to a 4-byte binary field is 999 999 999. In general, a binary field of n digits can have a maximum value of n 9s. This discussion assumes zero decimal positions.
Because a 2-byte field in binary format is converted by the compiler to a decimal field with 1 to 4 digits, the input value may be too large. If it is, the leftmost digit of the number is dropped. For example, if a four digit binary input field has a binary value of hexadecimal 6000, the compiler converts this to 24 576 in decimal. The 2 is dropped and the result is 4576. Similarly, the input value may be too large for a 4-byte field in binary format. If the binary fields have zero (0) decimal positions, then you can avoid this conversion problem by defining integer fields instead of binary fields.