Obtaining Ethernet IP information from a 1756-ENET

1. First create a USER DEFINED tag called IP, and configure it as shown below:
   
   
   
   
2. Create a CIP message instruction like the one shown below.
   
   NOTE: Tag B3.0 is not required.
   
   
   
   
   
3. Configure the CIP message as shown below.  Note that the destination tag ENET_IP_INFO
   is a tag of type IP (User Defined).
   
   
   
   
   
   
4. Also note that the values that come back into IPx will be in reverse order.
   
   Example:
   IP Address of 130.151.191.138  would come back as:
   
   ENET_IP_INFO.IP1 = 8Ah = -118 (SINT) = 138 (DINT)
   ENET_IP_INFO.IP2 = BFh = -65  (SINT) = 191 (DINT)
   ENET_IP_INFO.IP3 = 97h = -105 (SINT) = 151 (DINT)
   ENET_IP_INFO.IP4 = 82h = -126 (SINT) = 130 (DINT)
   
   Since the values that come back have to be stored in a SINT, you would need to move them to an INT or a DINT.
   
   Below, I use the BTD (Bit Field Distribute) functions to move the data.
   
   
   
   
   
   
5. To determine if the Modules Bootp is enabled, create a MSG instruction configured as shown below:
   
   
   
   
   Memory5 is a DINT array, 2 elements in length.
   
   -  If Memory5[0] = 0, then Bootp is DISABLED
   
   -  If Memory5[0] = 1, then Bootp is ENABLED
   
   
6. To enable or disabled Bootp, you would configure a MSG instruction as shown below:
   
   
   
    - Place a value of 1 into Memory5[0] to ENABLE bootp.
   
    - Place a value of 0 into Memory5[0] to DISABLE bootp.
   
   After changing the modules mode to bootp, the module will not request a bootp
   address until the next time it is power cycled.

Source : http://rockwellautomation.custhelp.com/app/answers/detail/a_id/18606/related/1