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Siemens CP 243-2 User Manual

Page 56

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Access to the Data of the AS-i Slaves

3-8

SIMATIC NET CP 243-2 AS-i Master

C79000-G8976-C142/02

3.2

Access to the Analog Data of the AS-i Slaves
(Slaves complying with Profile 7.3 or 7.4)

3.2.1

Addressing the Analog AS-i Slaves in the User Program

Requirements

Before you can access the I/O data of the AS-i slaves, the following requirements
must be met:

S

Deactivate the filtering of the analog inputs for the CP 243–2 in the system data
block of the S7–200 CPU.

S

Set the “PLC_RUN” bit (bit 7) in the digital control byte to ’1’ at the beginning of
the cyclic program.

S

Access to the I/O data of the slaves is then only allowed when the “CP_Ready”
bit (bit 1) in the digital status byte is set to ’1’.

The following explanations do not apply to analog slaves complying with profile 7.1
or 7.2. Analog value transfer for these slaves is not supported by the CP 243-2.

Access to the Analog Values

The CP 243-2 assigns four words in the input area and four words in the output
area for each AS-i slave. The PLC can write these values (analog outputs) or read
these values (analog inputs).

Assignment of the AS-i Analog Data

Bank Byte no. Meaning

32

0

Slave 1, channel 1, high byte

32

1

Slave 1, channel 1, low byte

32

2

Slave 1, channel 2, high byte

32

3

Slave 1, channel 2, low byte

32

4

Slave 1, channel 3, high byte

32

5

Slave 1, channel 3, low byte

32

6

Slave 1, channel 4, high byte

32

7

Slave 1, channel 4, low byte

32

8

Slave 2, channel 1, high byte

32

9

Slave 2, channel 1, low byte

32

10

Slave 2, channel 2, high byte

32

11

Slave 2, channel 2, low byte

32

12

Slave 2, channel 3, high byte

32

13

Slave 2, channel 3, low byte

32

14

Slave 2, channel 4, high byte

32

15

Slave 2, channel 4, low byte