Read_Parameter_String - Siemens SIMATIC NET IE/AS-INTERFACE LINK PN IO Manual

8.2.2.8

Read_Parameter_String

Meaning
With AS-i slaves with profile 7.4, this call can be used to read a parameter string
from the AS-i slave with the specified AS-i slave address.
The AS-i master returns up to 220 bytes of response data. The actual number of
parameter bytes sent by the AS-i slave is signaled by the AS-i master in byte 2.
The maximum number of parameter bytes is 220.
If the AS-i slave sends a string longer than 220 bytes, the AS-i master aborts the
string transfer and terminates the job with an error. The received data are then not
made available to the user program.
As long as the string transfer is active, there is no user/analog data exchange with
the addressed AS-i slave.
Structure of the RecordDataRead service − Index 27
Byte
Bit 7
0
1
2
3
4
...
221
222
IE/AS−INTERFACE LINK PN IO
Release 08/2018
C79000−G8976−C216−03
Bit 6 Bit 5 Bit 4
Version_hi = 0x00
Version_lo = 0x00
Number of string bytes
String byte 219 (may be irrelevant)
String byte 220 (may be irrelevant)
as of hardware version 1, as of firmware version V2.0
8 Using the Data Record Interface
Meaning
Bit 3 Bit 2
String byte 1
String byte 2
...
Bit 1 Bit 0
159