ABB S800 I/O Manual page 69

Section 4 Operation
Loading Parameters
At start-up, the configuration parameters are loaded by the FCI in the
NotConfigured state. When valid configuration parameters are written to the
module, it will change from the Not Configured state to the Ready state.
After entering the Ready state the module may be set to Operational.
The parameters do not need to be remembered on the modules after a reset of the
module since they are saved in the FCI.
Loading Invalid Parameters
If parameters that are in some way invalid are sent to a module, this is indicated
with a warning in the module status and by a diagnostic message. If channel
parameters are invalid an error on the channel is indicated.
Non-volatile Parameters
Each channel may, apart from the configuration parameters, also have non-volatile
parameters that are stored on the module and written during production and are not
changed by a running system.
OSP-Watchdog
The OSP-watchdog is a watchdog timer that all I/O modules with output channels
have. It supervises the communication to discover if the traffic on the ModuleBus is
interrupted. The OSP-watchdog is refreshed when the module is accessed. If this is
not done within the time limit the watchdog will force the module to the OSP state
(see
The OSP-watchdog is also activated when the PROFIBUS-DP/DPV1 watchdog has
elapsed. The supervision time for PROFIBUS-DP/DPV1 is defined in the
PROFIBUS configuration tool.
The watchdog on PROFIBUS must be enable to get the OSP function to work on
AO and DO modules at communication error on PROFIBUS.
The watchdog time-out should be set to at least four times the PROFIBUS's cycle
time.
3BSE020926-600
Module States on page 66).
I/O Module Functionality
69