Optionally, the tags value can be displayed as a text descriptor, for example ON, OFF, True, False, Run, Stop, Auto, Manual, HOLD etc.
If three bits are read or written from the field device, up to 8 state descriptors are used to display the 'State" of the tag's value. If a single bit is read or written form the device, then only two state descriptors are used.
Length State Descriptors Used
1-BIT STATE 0 and STATE 1
0, 1, 2, and STATE 3
3-BITS STATE 0 thru STATE 7
The value of the Tag read by calculation tags, accumulation tags, scripts, keymacros and user programs is always the integer representation (0 to 7). The tag descriptor fields can be read scripts and user programs (DESCR0 to DESCR7).
The value of the Discrete Tag on Displays and Dialog boxes will use the STATE descriptors specified her (STATE 0 to 7)
12 alphanumeric characters
Field Type: Text
Tag fields: .DESCR0 .DESCR1 .DESCR2 .DESCR3 .DESCR4 .DESCR5 DESCR6 .DESCR7
Figure 4-6 Change Dialog Box for 8-state (3 -bit) Discrete Tag
Figure 4-7 Change Dialog Box for 2-state (1-bit) Digital Tag
It is highly recommended to leave the NotUsed descriptor for states that will not be used. The Change Dialog box will show too many buttons is NotUsed is erased or replaced. For example, if it is a 1 bit length tag, then State0 Descriptor and State1 Descriptor should be changed, but the descriptor for States 2 to 7 should be left as NotUsed.