Siemens CP 243-1 IT, Техническое руководство

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Configuration 03/03
CP 243-1 IT
J31069-D0429-U001-A0-7618
76
Byte Offset in
Variable Memory
Name Description Data
Format
... ... ASCII
... COM_CHr_p ASCII
CRC section
The last two bytes
of the NDB CRC for all NDB
bytes without the
CRC section itself 2 bytes, hex The last two
bytes of the
NDB
Table 9 Structure of the NDB
Name Description Data
Format
<op>
Job type
Value range: R for read
W
for write
ASCII
<cnt>
Number of bytes to be transferred
Value range: 1 to 212 ASCII
<local_buffer> Address of the memory area in the local system
Value range:
VB0 to VBx, whereby x is the max. V address
ASCII
<remote_buffer> Address of the memory area on the communication partner
Value range:
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)
ASCII
Table 10 Configuration of the read/write jobs
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.