Siemens SIMATIC ET 200AL, System Manual

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Addressing via DHCP
10.3 Activate DHCP
Communication
368
Function Manual, 05/2021, A5E03735815-AJ
10.3 Activate DHCP
Requirements
• S7-1500 CPU firmware V2.9 or higher
Procedure
To activate DHCP for the PROFINET interface of an S7-1500 CPU, follow these steps:
1.
Select the PROFINET interface of the S7-1500 CPU in STEP 7.
2. In the properties of the interface, navigate to "Ethernet addresses" > "Internet Protocol
Version 4 (IPv4)".
3. Select the option "IP address of DHCP server".
Result
You have set the interface so that it obtains your IP address via a DHCP server.
"Use MAC address as client ID" is set as the operating mode for DHCP on the S7-1500 CPU.
How to adjust the client ID is described under Configuring the client ID (Page 368).
10.4 Configuring the client ID
The client ID
The S7-1500 CPU always identifies itself to a DHCP server with the client ID (DHCP option 61).
The client ID is interface specific.
The S7-1500 CPU supports the following two operating modes with regard to the client ID:
•
Use the MAC address as the client ID: The MAC address of the CPU is used as the client ID
for the DHCP client. Note, if you execute a device exchange of the CPU in this operating
mode, the MAC address and therefore also the client ID changes.
• User-defined client ID: With this option you specify the client ID in the configuration in
STEP 7. You also have the option of adapting the client ID during runtime, for example, in
the user program using the "CommConfig" instruction.
If you perform a device exchange of the CPU in this operating mode, the new CPU is
assigned the configured client ID.
Requirement
• You have activated address assignment via DHCP for the interface.