Understanding Fast Device Replacement
 
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About Fast Device Replacement
Fast device replacement (FDR) configuration is accessible only through the embedded Web pages.
FDR with role name allows replacement without reconfiguring the device.
Choosing to use FDR depends upon both your automation environment and your needs for replacement capabilities.
Benefits of FDR:
Choice
Reason for Using
Using FDR
FDR provides the following advantages:
  • centralized IP management
  • centralized storage of configuration (runtime) parameters
  • A technician only needs to know the device’s role name to replace a device.
  • Configuration parameters are never lost.
Not using FDR
No FDR server is available.
Using FDR requires assigning a unique role name to your Momentum 170ENT11001.
FDR and Role Names
WARNING
UNEXPECTED APPLICATION BEHAVIOR - DUPLICATE ROLE NAME"
Ensure that:
  • ALL devices have a unique role name.
  • the unique role name appears in only one DHCP/FDR server table.
A non-unique role name may cause an DHCP/FDR server to serve a configuration belonging to another device.
Failure to follow these instructions can result in death, serious injury, or equipment damage.
Inherent in the discussion of FDR is the idea of a role name.
The Momentum 170ENT11001:
A device that does not have a role name does not participate in FDR.
A role name is a logical name that you assign to a device, a logical name that has meaning in your application.
Valid role names are alphanumeric and underscore, with a maximum of 16 characters.
Some examples of role names might be:
NOTE: The logical role name should be written on the device.
Device Uses a Role Name to Boot Up–FDR Server Responds
The Momentum 170ENT11001 will:
Step
Action
1
Transmit DHCP Discover messages to request its IP parameters from an FDR server.
2
If an FDR server responds with an IP address, the Momentum 170ENT11001:
  1. uses the IP parameters received
  2. attempts to get its configuration (runtime) parameters from an FDR server
    • Configuration parameters are served from an FDR server.
      Device uses those configuration parameters and is operational (I/Os are running).
    • Configuration parameters are not served from an FDR server, and the configuration parameters are stored in FLASH, and the ConfigFallBack flag* check box is selected.
      Device uses configuration parameters and is operational.
    • \Configuration parameters are not served from an FDR server, and configuration parameters are not stored, and/or ConfigFallBack* check box is not selected.
      Device goes to safe I/O mode and uses the IP address from FDR server.
      I/Os are not operational.
      Blink code on LAN ST indicator (LED): 8 flashes
    * Fall Back to Stored Application Parameters in the absence of an FDR server check box appears on the Current Communication Adapter Configuration Web page.
Device Uses a Role Name to Boot up–FDR Server Does Not Respond
The Momentum 170ENT11001 will:
Step
Action
1
Transmit DHCP Discover messages to request its IP parameters from an FDR server.
2
If an FDR server does not respond with an IP address, the device:
  1. checks if both IP parameters exist in FLASH and IPFallBack flag* is selected
  2. IP parameters exist in FLASH and IPFallBack flag is selected
    Device uses stored IP parameters, and checks for configuration (runtime) parameters in FLASH.
    • Configuration parameters exist, and ConfigFallBack flag** is selected.
      Device uses configuration parameters and is operational.
    • Configuration parameters do not exist, and/or the ConfigFallBack flag is not selected.
      Device goes to safe I/O mode and uses IP address from FLASH.
      I/Os are not operational.
      Blink code on LAN ST indicator (LED): 6 flashes
  3. IP parameters do not exist in FLASH and/or IPFallBack flag is not selected.
    Device uses default IP parameters and goes to safe I/O mode.
    I/Os are not operational.
    Blink code on LAN ST indicator (LED): 8 flashes
*Fall Back to Stored Application Parameters in the absence of an FDR server check box appears on the Current Communication Adapter Configuration Web page.
**The check box appears on the Current IP Configuration page.
Note: In the absence of a configured role name, the Momentum 170ENT11001 will not participate in FDR.