Replacing a Device (FDR)

Overview

This topic describes replacing a device and how to configure the device after it has been replaced.

configuration is accessible only through the embedded Web pages.

Fast Device Replacement

The FDR service offers you an easy method of handling device replacement with minimal disruption of service. Should a device fail, replacing that device is easy. The technician can then get a new device from stores, enter the corresponding role name into the device, and place the device in the system. When the new device is physically connected to the network, the system (including the new device) is able to:

provide the replacement device with the IP address of the previous device
ensure that new device is functioning properly
restore the I/O device application parameters in order to restart the device with the same configuration as before the failure

FDR enables you to avoid configuring a new device when a device is replaced.

FDR is implemented using the combination of DHCP and FTP standard protocols.

Obtaining IP Parameters using FDR

When the device boots up, it attempts to obtain its IP parameters from the FDR server using the DHCP protocol. After receiving its IP parameters, the Momentum 170ENT11001 will check for agreement between the served IP parameters and the IP parameters stored in FLASH. If the parameters agree, it will simply apply these parameters to the current configuration.

In the event that the IP parameters do not agree and prior to using the parameters, the Momentum 170ENT11001 will:

overwrite the saved IP parameters with the served IP parameters to maintain consistency across parameter databases

If, for what ever reason, the Momentum 170ENT11001 could not get the IP parameters from the FDR server, the Momentum 170ENT11001 will check the IPFallBack bit, and, if set, will use the stored IP parameters. If the IPFallBack bit is not set, the Momentum 170ENT11001 will continue to request its IP parameters for approximately 5 minutes.

Into Safe I/O Mode

After the request parameters time has timed out, the Momentum 170ENT11001 will go to safe I/O mode with its default IP parameters and blink the default IP indication on the LAN_ST LED.

Access to the I/O is disabled.

Obtaining Configuration (Runtime) Parameters using FDR

After receiving its IP parameters, the device attempts to obtain its configuration (runtime) parameters.

The device:

checks if there are any outstanding updates:
- If outstanding updates exist, the device attempts to push these changes to the FDR server.
- If no outstanding updates exist, the device attempts to obtain its configuration (runtime) parameters form the FDR server using the FTP protocol.
after checking for updates and if the FDR server responds with the device’s configuration (runtime) parameters:
- checks for agreement between the served configuration parameters and the configuration parameters stored in FLASH:

In the event that, for whatever reason, the Momentum 170ENT11001 could not get access to the parameter file on the FDR server, the Momentum 170ENT11001 will check the ConfigFallBack bit, and, if set, will use the parameters stored in FLASH. If the ConfigFallBack bit is not set, the Momentum 170ENT11001 will go to safe I/O mode with served IP parameters.

Finishing the Process

When the initialization phase is completed successfully, the communication adapter is ready to communicate using the Modbus TCP/IP protocol. The RUN LED will be on steady. Access to the I/O is enabled by finishing the process.