Address Assignment With The Primary Setup Tool - Siemens SCALANCE W786-xPRO Operating Instructions Manual

5.2.4

Address assignment with the Primary Setup Tool

Introduction
The PST (Primary Setup Tool) is capable of assigning such an address to unconfigured
devices without an IP address.
Prerequisite
This is possible only when the devices have a default Ethernet (MAC) address and are
reachable online in the network.
Note
For more detailed information, refer to the Primary Setup Tool configuration manual.
You will find the PST at Siemens Automation and Drives Service & Support on the Internet
under entry ID 19440762. The URL for this entry is:
http://support.automation.siemens.com/WW/view/en/19440762
SCALANCE W786-xPRO
Operating Instructions, Release 08/2007, C79000-G8976-C221-02
Note
DHCP uses a mechanism with which the IP address is assigned for only a short time
(lease time). If the device does not reach the DHCP server with a new request on expiry
of the lease time, the assigned IP address, the subnet mask and the gateway are
changed to static entries.
The device therefore remains accessible under the last assigned IP address even without
a DHCP server. This is not the standard behavior of office devices but is necessary for
problem-free operation of the plant.
Since the DHCP client also sends a RELEASE to the server, the server can assign this
address to a further device so that inconsistencies can occur within the network.
Remedy:
After disabling DHCP, you should therefore
• change the IP address of the device to an address not assigned by DHCP
or
• remove the IP address assigned to the device from the address pool of the DHCP
server.
Working with a mixture of dynamic address assignment and statically assigned
addresses is not advisable.
Configuration / project engineering
5.2 Assignment of an IP address
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