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5.1.6
Reply-Update-Ptr/ SDN-/DDB-Tln-Tab-Ptr:
The "Reply-Update-Ptr/ SDN-/DDB-Tln-Tab-Ptr" pointer points to the indication
reply buffer or to the SDN/DDB-Tln list (see also SDN-/DDB filter). The data buffers
must be located above the UMBR-PTR in the SPC 4-2.
Structure
The structure of the SDN-/DDB-Tln list is described in the following table:
SDN-/DDB-Tln-List (Optional
tab-data-
length
don't care
Request-
SA 1
Request-
SSAP 1
........
Request-
SA n
Request-
SSAP n
Table 5-4 : SDN-/DDB-Tln List
SDN Frames
All SDN frames (except for SM-TIME, that is always indicated) and DDB response
frames can be filtered by the SPC 4-2 using the node table. The "Request-SA" and
the "Request-SSAP" are defined in this node table per entry. An indication results
only if the received SDN-/DDB frame is validated by one of the entries.
SDN Filter
The SDN-/DDB filter is active when the "SDN/DDB Filter" bit is set in the receive
SAP. The node table is addressed using the "SDN-/DDB-Tln-Tab-Ptr" pointer. If
"tab-data-length"=0, there is no validation of the SDN-/DDB-Tln list.
40
)
8 bits
Number of entries in the SDN-/DDB-Tln list. The physical
length of the list is (n*2)+2 bytes for "n" entries
8 bits
8 bits
First entry in the DDB-Tln list, meaning as for Request-SA
8 bits
First entry in the DDB-Tln list, meaning as for Request-
SSAP.
8 bits
nth entry in the DDB-Tln list, meaning as for Request-SA
nth entry in the DDB-Tln list, meaning as for Request-
8 bits
SSAP.
PROFIBUS Controller SPC 4®-2 LF
C79000-G8976-C157-3
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