Siemens SIMATIC NET CP 243-2 Manual page 54

Access to the Data of the AS-i Slaves
Example
Figure 3-1 shows an example of the CP 243-2 addressing four AS-i slaves. In the
example, m = 0 is the start address for the input data and n = 0 is the start address
for the output data.
The bits relevant for the user program (existing AS-i slaves) are shown on a gray
background. The bits on a white background are irrelevant for the user program.
CP 243-2
16 input bytes
0
Bit 3 Bit 2 Bit 1 Bit 0
Slave 2
1
Bit 3 Bit 2 Bit 1 Bit 0 Bit 3
Slave 4
2
. Bit 2 Bit 1 Bit 0
Bit 3
.
.
Slave 30
15
Bit 2 Bit 1 Bit 0
Bit 3
7 6 5 4
Slave no. 2
AS-i slaves
4 I module
4 I module
Figure 3-1
In the figure above, for example, the 2I/2O module (AS-i slave number 3 with two
inputs and two outputs) occupies bits 0 and 1 in input byte 1 and bits 2 and 3 in
output byte 1.
The assignment of the AS-i terminals of the bus modules to the data bits of the
input/output bytes is shown below based on the example of slave number 3:
Input byte 1
Output byte 1
Terminal 4 on the AS-i bus module
Terminal 3 on the AS-i bus module
3-6
Slave 1
Bit 3 Bit 0
Bit 2 Bit 1
Slave 3
Bit 2 Bit 1
Bit 0
Slave 5
Bit 1 Bit 0
Bit 3 Bit 2
Slave 31
Bit 3 Bit 2 Bit 1 Bit 0
3 2 1 0
Slave no. 3 Slave no. 4
2 I/2 O module
Terminal 2 on the AS-i bus module
Terminal 1 on the AS-i bus module
16 output bytes
Slave 1
0
Bit 0
Bit 2 Bit 1 Bit 3 Bit 1
Bit 3 Bit 2
Slave 2 Slave 3
1
Bit 3 Bit 2 Bit 1 Bit 0 Bit 3
Bit 2 Bit 1
Slave 4
Slave 5
2
Bit 2
Bit 3 Bit 0 Bit 3 Bit 1
Bit 1 Bit 2
.
.
.
Slave 30 Slave 31
15
Bit 3 Bit 2 Bit 1 Bit 0 Bit 3 Bit 2 Bit 1
7 6 5 4 3 2 1
Slave no. 31
4 O module 4 I/4 O module
1 0
3 2
SIMATIC NET CP 243-2 AS-i Master
C79000-G8976-C142/02
Bit 0
Bit 0
Bit 0
Bit 0
0
Bit no.
Bit no.