Structure Of The Internet Data Block (Idb); Table 9 Structure Of The Ndb; Table 10 Configuration Of The Read/Write Jobs - Siemens SIMATIC NET CP 243-1 IT Technical Manual

Configuration
Byte Offset in
Variable Memory
... ...
... COM_CHr_p
CRC section
The last two bytes CRC for all NDB
of the NDB bytes without the
CRC section itself
Table 9
Name
<op> Job type
Value range: R for read
<cnt> Number of bytes to be transferred
Value range: 1 to 212
<local_buffer> Address of the memory area in the local system
Value range:
<remote_buffer> Address of the memory area on the communication partner
Value range:
Table 10
4.4.5

Structure of the Internet Data Block (IDB)

The IDB is created by the Internet wizard in STEP 7 Micro/WIN 32. The structure of
the IDB is shown in the following table.
The IDB immediately follows the NDB in variable memory. Since the length of the
NDB varies with the current configuration, no general start address can be given
for the IDB. The byte offsets in the table below all refer to this start address.
76
Name
2 bytes, hex
Structure of the NDB
Description
W for write
VB0 to VBx, whereby x is the max. V address
IB0 to IBx, whereby x is the max. input address
(S7-200 / S7-300 / S7-400)
QB0 to QB, whereby x is the max. output address
(S7-200 / S7-300 / S7-400)
MB0 to MBx, whereby x is the max. marker address
(S7-200 / S7-300 / S7-400)
VB0 to VBx, whereby x is the max. variable address
(S7-200)
DB0.DBB0 to DBx.DBBy, whereby x is the max DB
number, and y is the highest address in the data block
within the DB (S7-300 / S7-400)
Configuration of the read/write jobs
Description
J31069-D0429-U001-A0-7618
03/03
Data
Format
ASCII
ASCII
The last two
bytes of the
NDB
Data
Format
ASCII
ASCII
ASCII
ASCII
CP 243-1 IT