Siemens SIMATIC S5 CP 523 Manual page 148

CP 523
7.4 CP 523 Feedback Information
The CP 523 has an eight-byte transfer memory for data exchange with the CPU.
The CP 523 reads the data from the transfer memory and updates the transfer memory with
current values only when the start address of the module has been written into word 0 of the
transfer memory with T PW in the user program. The current data can then be read in the user
program with L PW statements.
CPU transfers job
request in word 0 of
the transfer memory
*
(T PW X).
* 5.2
The meaning of the data written into the transfer memory by the CP depends on:
• the job number that was transferred to the CP in word 0
and
• the initialized mode
Table 7-21. Job Requests and the Associated Feedback Information
Job Requests
0000 : Read status byte, status of I/O device
H
and current clock data ( 7.4.1)
1000 : Set clock
H
( 6.7.2)
90XX : Transfer parameter setting data
H
( 7.3.2)
A0XX : Coordinate data transfer
H
( 7.6 and 7.7)
EWA 4NEB 811 6044-02a
CP reads bytes 0 to
7 of the transfer
memory.
Figure 7-6. Using the Transfer Memory
CP writes current
data into bytes 0
to 7 of the transfer
memory.
Initialized Return Info from CP
Mode
1, 2, 3
1, 2, 3
1, 2
3
1
2
3
Communications Mode
CPU can read the
current data from
the transfer
memory (L PW X).
See Section
7.4.1
7.4.1
7.4.1
7.4.1
7.4.2
7.4.2
7.4.2
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