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Data Size/Format, and Decimal Bits 0, 1, 2 and 4, 5, 6
The least significant byte of the format word is used to specify the size, the format, and the
position of the decimal point in a displayed value. The selection of signed or unsigned affects
the editing range of a value. Unsigned values are restricted to positive numbers. Signed
values can be either positive or negative. Figure D-18 shows the placement of the data
size/format and decimal point bits in byte 1 of the format word.
Unsigned words have a range from 0 to 32,767
Signed words have a range from –32,768 to 32,767
Unsigned double words have a range from 0 to 2,147,483,647
Signed double words have a range from –2,147,483,648 to 2,147,483,647
Real (floating-point) numbers have a range from
Note
Due to the size of the display, the TD 200 can display real numbers between 1*10
19
9.99999*10
19
9.99999*10
S– Data Size/Format
0 – No data value
1 – Signed word value
2 – Signed double word value
3 – Unsigned word value
4 – Unsigned double word value
5 – Real (floating-point) value
6 – Reserved
7 – Reserved
Figure D-18 Bit Values of Byte 1 of the Format Word
SIMATIC TD 200 Operator Interface
C79000-G7076-C205-04
–7
. Values smaller than 1*10
are displayed as "eeeeee".
Format Word
Byte 0
Byte 1
Byte 2
MSB of
LSB of
MSB of
Format
Format
Data
MSB
7 6
5
4
0
S S 0
D– Placement of the Decimal Point
0 – No decimal point
1 – One digit to the right of the decimal point
2 – Two digits to the right of the decimal point
3 – Three digits to the right of the decimal point
4 – Four digits to the right of the decimal point
5 – Five digits to the right of the decimal point
6 – Six digits to the right of the decimal point
7 – Seven digits to the right of the decimal point
TD 200 Parameters and Messages
–38
1.7549*10
to
are displayed as "0", and values larger than
Optional Data Value
Byte 3
Byte 4
Byte 5
LSB of
Data
LSB
3
2
1
0
D
D
D
38
3.40282*10
.
–7
and
D-17
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