Configuration
3.4 Other options when configuring a CP 243-1
CP 243-1
72 Operating Instructions, 03/2012, C79000-G8976-C244-02
3.4.3 Structure of the network parameter block (NPB)
The CP 243-1 creates this data block automatically based on the current set of network
parameters. It contains the currently used TCP/IP parameter values if the CP 243-1 was
configured correctly. If configuration errors occurred, the NPB does not contain valid entries.
Byte offset in
variable memory
Description Calculation of the
value
Data
Format
Example
108-109 Common flag byte
• Bit [0] duplex mode
– 0: half duplex
– 1: full duplex
• Bit [1] data rate
– 0: 10 Mbps
– 1: 100 Mbps
• Bit [2] Autonegotiation
– 0: No autonegotiation
– 1: Autonegotiation
• Bit [3] aut. address
assignment
– 0: use configured
network parameters
– 1: BOOTP/DHCP
• Bit [4] protocol
– 0: BOOTP
– 1: DHCP
• Bit [5-15] not used
Depends on the
current configuration
2 bytes, hex 16#04:
Autonegotiation,
use configured
network parameters
110-113 Current IP address Depends on the
current configuration
4 bytes, hex 192.12.45.23:
16#C00C2D17
114-117 Current subnet mask Depends on the
current configuration
4 bytes, hex 255.255.255.0:
16#FFFFFF00
118-121 IP address of the current
gateway
Depends on the
current configuration
4 bytes, hex 192.12.45.24:
16#C00C2D18
122-127 MAC address Read from hardware 6 bytes, hex 16#080006021F04
08-00-06-02-1F-04
Structure of the NPB
3.4.4 Structure of the network data block (NDB)
The NDB is created by the Internet wizard in STEP 7 Micro/WIN 32. The read/write requests
possible for clients are configured in this data block. Up to 32 read/write requests can be
configured for each of the 8 possible S7 channels. if the CP 243-1 is the server on a
channel, there is no entry in the NDB structure for this channel.