B&B Electronics VFG3000 - Manual - Manual (Page 90)

E DITING S TRING T AGS V LINX F IELDBUS G ATEWAY M ANAGER U SER M ANUAL
P AGE 74
T
HE
D
ATA
T
AB
(V
ARIABLES
)
The Data tab of a string variable contains the following properties...
• The Mapping property is used to specify if the variable is to be mapped to a
register in a remote device, or if it exists only within the terminal. If you press
the arrow button and select a device name from the resulting menu, you will be
presented with a dialog box that will allow a PLC register to be selected.
• The Encoding property is used to specify how text will be packed into mapped
registers that contain more than 8 bits of data. Selecting unpacked will store one
character per register no matter how large the register, leaving the high-order bits
empty. Selecting low-to-high packed mode will store one character in each 8 bits
of the target register, storing the first character in the lowest order bits. Selecting
high-to-low packed mode will store one character in each 8 bits of the target
register, storing the first character in the highest order bits.
• The Length property is used to indicate how many characters of storage should
be allocated for this string. A value need only be entered if you have configured
the variable for retentive storage. Strings that are kept in the terminal’s RAM and
not committed to FLASH have no practical limit on their length.
• The remainder of the properties are as described for flag variables.