Siemens CP 243-2 installation instructions AS-i slaves, Output byte

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

Slave 1

Bit 3

Bit 2

Bit 1

Bit 0

Bit 3

Bit 2

Bit 1

Bit 0

1

Slave 2

Slave

3

Bit 3

Bit 2

Bit 1

Bit

0

Bit 3

Bit 2

Bit 1

Bit 0

2

Slave 4

Slave 5

Bit 1

Bit 0

.

Bit 3

Bit 2

Bit 3

Bit 2

Bit 1

Bit 0

.

.

15

Slave 30

Slave 31

Bit 3

Bit 2

Bit 1

Bit 0

Bit 3

Bit 2

Bit 1

Bit 0

7

6

5

4

3

2

1

0

16 output bytes

0							Slave 1
	Bit 3		Bit 2	Bit 1	Bit 0	Bit 3		Bit 2	Bit 1	Bit 0
		Slave 2					Slave		3
	Bit 3		Bit 2	Bit 1 Bit 0		Bit 3		Bit 2	Bit 1	Bit 0
2			Slave 4				Slave 5
	Bit 3		Bit 2	Bit 1	Bit 0	Bit 3		Bit 2	Bit 1	Bit 0
			Slave 30				Slave 31
15	Bit 3		Bit 2	Bit 1	Bit 0	Bit 3		Bit 2	Bit 1	Bit 0

AS-i slaves

Slave no. 2

4 I module

Slave no. 3

2 I/2 O module

Slave no. 4

4 O module

Slave no. 31

4 I/4 O 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:

1 0 Bit no.

Input byte 1

Terminal 2 on the AS-i bus module

Terminal 1 on the AS-i bus module

3 2 Bit no.

Output byte 1

Terminal 4 on the AS-i bus module

Terminal 3 on the AS-i bus module

3-6	SIMATIC NET CP 243-2 AS-i Master
	C79000-G8976-C142/02