Siemens SIMATIC NET CP 243-1 IT Technical Manual page 75

03/03
The structure of the NDB is shown in the following table. The identifiers for
read/write jobs are represented by the letters n, m, p = 0, ..., 31 and the channel
identifiers with the letters r = 0, ...,7.
Byte Offset in
Variable Memory
Header
128-129 NDB_LENGTH
Entries for the first client
130 COM_CH0_ID
131 COM_CH0_OFF
132 COM_CH0_LEN0
...
n+132 COM_CH0_LENn
n+5 COM_CH0_0
... ...
+
n 5
COM_CH0_n
−
n 1
∑
+
COM _ CH 0 _ LENi
i = 0
Entries for the second client channel
... COM_CH1_ID
... COM_CH1_OFF
... COM_CH1_LEN0
... ...
... COM_CH1_LENm
... COM_CH1_0
... ...
... COM_CH1_m
... ...
Entries for the rth client channel
... COM_CHr_ID
... COM_CHr_OFF
... COM_CHr_LEN0
... ...
... COM_CHr_LENp
... COM_CHr_0
CP 243-1 IT
J31069-D0429-U001-A0-7618
Name
Specifies the length of the NDB
Identifier of the first client channel
Specifies the offset to the first communication
block (COM0)
Specifies the length of the first communica-
tion block (COM0)
Specifies the length of the COMn structure
COM0 structure for read/write job 0 for first
client channel
"<op>=<cnt>,<local_buffer>,<remote_buffer>"
(For a description, see Table 10)
...
COMn structure for read/write job n for first
client channel
"<op>=<cnt>,<local_buffer>,<remote_buffer>"
(For a description, see Table 10)
Identifier of the second client channel
(up to 8 channels)
Identifier of the last client channel
Description
Configuration
Data
Format
2 bytes, hex
1 byte, hex
1 byte, hex
1 byte, hex
n bytes
1 byte, hex
ASCII
ASCII
ASCII
1 byte, hex
1 byte, hex
1 byte, hex
1 byte, hex
1 byte, hex
ASCII
ASCII
ASCII
1 byte, hex
1 byte, hex
1 byte, hex
1 byte, hex
1 byte, hex
ASCII
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