Siemens SIMATIC TD 200, User Manual

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D-18
SIMATIC TD 200 Operator Interface
C79000-G7076-C272-01
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 1.7549*10
-38
to
3.40282*10
38
.
Note
Due to the size of the display, the TD 200 can display real numbers between
1*10
-7
and 9.99999*10
19
. Values smaller than 1*10
-7
are displayed as “0”, and
values larger than 9.99999*10
19
are displayed as “eeeeee”.
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
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
Format Word Optional Data Value
Byte 0 Byte 1 Byte 2 Byte 3 Byte 4 Byte 5
MSB of
Format
LSB of
Format
MSB of
Data
LSB of
Data
0
S
S S 0 D D
7 6 5 4 3 2 1 0
MSB LSB
D
Figure D-18 Bit Values of Byte 1 of the Format Word
TD 200 Parameters and Messages