Configuration set-up
In SctApi.cxx::cacheModuleConfig SctApi loads module configurations from the configuration service.
Here it checks for the "Off-ROD" condition and then puts the module in to an (SctApi internal) list attached to each ROD. In the ROD with the redundant connection, it is placed at a position above the standard 48. This number is constructed and stored in the offRODTTC list.
The on-ROD configuration has the rTTC member set to OFF_ROD_TTC to signify this to the ROD.
The off-ROD configuration has the correct TTC value and the rx fibres set to DATA_LINK_OFF.
- Oops!! a bug. Currently the off ROD configuration is not constructed!! **
ROD configuration
In SctApiMConf?.cxx::setABCDModules the configuration is sent to the ROD. This involves sending the configurations in the standard module list. The offRODTTC list of each ROD is then checked and those configurations are also sent to the ROD.
When sendABCDModules is called a ROD will iterate over the whole of its list including the configurations stored above position 48.
Caveats
The system doesn't expect a ROD to be present in the configuration if there are no modules to do a scan on it. Thus an extra module may need including on the off-ROD to make it run (this can probably be fixed).
You can't run normal scans as the trigger for the redundant connection to the module would have to come from a ROD that can't synchronise itself with the ROD receiving the data. TIM scans should be fine. (this can't be fixed, it may be flagged to MRS already, but the module could also be removed).