Write_Ctt2_String - Siemens SIMATIC NET IE/AS-INTERFACE LINK PN IO Manual

8.2.2.12

Write_CTT2_String

Meaning
Using this call, a CTT2 request according to AS-i slave profile
"CombinedTranslationType2" can be sent to the AS-i master as a byte string. This
forwards the string bytes to the AS-i slave address specified in the send buffer.
With this call, a string with a maximum of 220 bytes is transferred to the
AS-i master. The actual number of string bytes to be sent to the AS-i slave is
calculated by the AS-i master from byte 2 of the send buffer (number of string
bytes). The number of string bytes is set by the user program.
The CTT2 request is replied to by the addressed AS-i slave with a CTT2 response.
This response can be fetched with the "Read CTT2 request" call.
The structure of the CTT2 request or CTT2 response (code, index, ...) always
begins with string byte 1. For more detailed information, refer to the relevant AS-i
slave description.
As long as the string transfers are handled on AS-i, there is no cyclic user
data/analog data transfer with the addressed AS-i slave (this does not apply to
digital I/O bits).
Due to the type of protocol, the transfer of approximately 200 bytes can take up to
half a minute.
Structure of the RecordDataWrite service − Index 31
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
163