Siemens SIMATIC ET 200AL, System Manual

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Addressing via DHCP
10.2 DHCP with DNS
Communication
Function Manual, 05/2021, A5E03735815-AJ
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Configuring a domain in STEP 7
To configure the domain in STEP 7, follow these steps:
1.
Select the S7-1500 CPU in STEP 7.
2. In the properties of the CPU, navigate to "Advanced configuration" > "Host and domain
name" > "Host and domain name configuration" > "Domain".
3. For "Domain configuration:" select "Set domain in the project" from the drop-down list.
4. Enter your desired domain under "Domain:".
Only if you have configured the host and domain name in STEP 7, the full name is displayed
for "Full name:".
Assigning a domain in the user program
To assign the domain in the user program, follow these steps:
1.
Select the S7-1500 CPU in STEP 7.
2. In the properties of the CPU, navigate to "Advanced configuration" > "Host and domain
name" > "Host and domain name configuration" > "Domain".
3. Under "Hostname configuration:" select "Set domain directly on the device (for example PLC
program, display)" in the drop-down list.
4. Call the instruction "CommConfig" in the user program. The DATA parameter must point to a
UDT "Conf_Domainname" where the domain name is specified.
You can find additional information on the "CommConfig" instruction and on the UDT "Conf-
Domainname" in the STEP 7 online help.
Rules for maximum lengths of host name, domain and client ID
Note the following maximum lengths in bytes. One byte corresponds to one character:
•
Host name: Maximum 63 bytes
• Domain: Maximum 252 bytes
• Client ID: Maximum 254 bytes
• Host + Domain name : Maximum 254 bytes
• Host + Domain name + Client ID: Maximum 260 bytes
Applies only when host name and domain must be sent to the DHCP server.