DCS has no way to push information to SIEM or syslog servers, unlike SEP for example.
I only have experience assisting with IBM Tivoli when it comes to this so, not sure what facilities QRadar has, but with Tivoli I believe it was possible to use a SQL connector to query the DB attached to DCS for event and status information, and this was deemed to be one of the most efficient ways to integrate into SIEM.
I'm by no means a SIEM expert however. But from a DCS perspective, events need to be pulled, and doing it from the DB is generally the best way. Specifically CSPEVENT_VW for event data, and ASSET_HEALTH_VW for asset information.