Communication
C3I22T11
334 192-120114 N5 C3I22T11 June 2008
5.4.5.4 Data formats of the bus objects
In this chapter you can read about:
Integer formats................................................................................................................. 334
Unsigned - Form
ats ......................................................................................................... 334
Fixed point format E2_6................................................................................................... 334
Fixed point format C4_3 .................................................................................................. 335
Bus format Y2 and Y4...................................................................................................... 335
Bit sequence V2............................................................................................................... 336
Byte string OS.................................................................................................................. 336
Integer formats
Twos complement representation;
The highest order bit (MSB) is the bit after the sign bit (VZ) in the first octet.
VZ == 0: positive numbers and zero; VZ == 1: negative numbers
Type Bit 8 7 6 5 4 3 2 1
Integer 8
length: 1 Byte
VZ 2
6
2
5
2
4
2
3
2
2
2
1
2
0
Integer 16
MSB VZ 2
14
2
13
2
12
2
11
2
10
2
9
2
8
Length: 1 Word LSB 2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
Integer 32
MSB VZ 2
30
2
29
2
28
2
27
2
26
2
25
2
24
Length: 2 Words
2
23
2
22
2
21
2
20
2
19
2
18
2
17
2
16
2
15
2
14
2
13
2
12
2
11
2
10
2
9
2
8
LSB 2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
Unsigned - Formats
Type Bit 8 7 6 5 4 3 2 1
Unsigned 8
Length: 1 Byte
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
Unsigned 16
MSB 2
15
2
14
2
13
2
12
2
11
2
10
2
9
2
8
Length: 1 Word LSB 2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
Unsigned 32
MSB 2
31
2
30
2
29
2
28
2
27
2
26
2
25
2
24
Length: 2 Words
2
23
2
22
2
21
2
20
2
19
2
18
2
17
2
16
2
15
2
14
2
13
2
12
2
11
2
10
2
9
2
8
LSB 2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
Fixed point format E2_6
Linear fixed point value with six binary places after the decimal point. 0 cor-
responds to 0, 256 corresponds to 2
14
(0x4000).
Twos complement representation;
MSB is the bit after the sign bit
VZ == 0: positive numbers and zero;
VZ == 1: negative numbers
Type Bit 8 7 6 5 4 3 2 1
E2_6
MSB VZ 2
8
2
7
2
6
2
5
2
4
2
3
2
2
Length: 1 Word LSB 2
1
2
0
2
-1
2
-2
2
-3
2
-4
2
-5
2
-6