No. 43: Read_String - Siemens SIMATIC ET 200SP Manual

9.4.32

No. 43: Read_String

Significance
This command causes the AS-i slave to read a diagnostics string in accordance with AS-
i slave profile 7.4 with the AS-i slave address specified in the send buffer. The AS-i master
supplies up to 221 bytes of reply data. The AS-i master signals the actual number of
diagnostics bytes sent by the AS-i slave in Byte 0 of the receive buffer.
If the AS-i slave sends a diagnostics string longer than 220 bytes, the AS-i master aborts
string transfer and terminates the job with an error. The received data is not made available
to the user program.
While transmission of the diagnostics string is being executed, there is no transfer of user
data / analog data with the addressed AS-i slave.
Structure of the job data in the send buffer
Table 9- 61 Structure of the job data in the send buffer
Byte
0
1
Structure of the reply data in the receive buffer
Table 9- 62 Structure of the reply data in the receive buffer
Byte
0
1
2
...
n - 1
n
Maximum value for n = 220
AS-Interface master CM AS-i Master ST (3RK7137-6SA00-0BC1)
Manual, 07/2017, A5E02655262020A/RS-AD/004
Significance
Command number: 43
H
Slave address
Significance
Number of diagnostics bytes
Diagnostic string byte 1
Diagnostic string byte 2
...
Diagnostic string byte n - 1
Diagnostic string byte n
Using the command interface
9.4 Description of the AS-i commands
151