Siemens SIMATIC NET S7-300 Manual page 177

6.6 Subfield types
Different parameters are required depending on the parameter field. Each
parameter is described by a subfield. Which subfields are required is explained in
the descriptions of the system data and the connection types in the previous
sections.
Each subfield consists of the specific parameter section and the header (4 Byte).
Example
The following excerpt from a CONF_DB illustrates the structure of a subfield based
on the example of the SUBNET_MASK subfield type.
Address
+14.0
+0.0
Header
+2.0
+4.0
+0.0
+1.0
Parameter
+2.0
+3.0
=4.0
=8.0
In total, the following subfield types are available:
Table 6-10
Subfield Subfield type
1)
ID
1 SUB_IP_V4
2 SUB_NETMASK
3 SUB_DNS_NAME
4 SUB_DNS_SERV_ADDR
8 SUB_DEF_ROUTER
9 SUB_LOC_PORT
10 SUB_REM_PORT
11 SUB_LOC_TSAP
S7-CPs for Industrial Ethernet Configuring and Commissioning
Release 01/2007
C79000-G8976-C182-07
Name Type
Sub_field_2 STRUCT
Sub_field_ID INT
Sub_field_len INT
Parameter STRUCT
Value_1 BYTE
Value_2 BYTE
Value_3 BYTE
Value_4 BYTE
END_ STRUCT
END_ STRUCT
Subfield length
(in bytes)
4 + 4
4 + 4
Length of DNS
name + 4
4 + 4
4 + 4
2 + 4
2 + 4
TSAP length + 4 Local TSAP
6 Programmed Communication Connections
Initial Value
// Subfield 2 type SUBNET_MASK
2 // Subfield ID
8 // Total length of the subfield in bytes
Parameter range of SUBNET_MASK
B#16#FF
B#16#FF
B#16#FF
B#16#0
Meaning of the Parameter
IP address according to IPv4
Subnet mask
DNS name
DNS server address
IP address of default router
Local port
Remote port, also for E-mail
connections
Comment
A -177