70 likes | 197 Views
EPICS – ACNET Issues. OAC Solution. OAC Summary. AN OAC could do an adequate job of implementing a gateway for EPICS readings and settings to some degree. Issues such as precise timing, data correlation, or adding an “accelerator time” timestamp will take more thought and work.
E N D
EPICS – ACNET Issues OAC Solution
OAC Summary • AN OAC could do an adequate job of implementing a gateway for EPICS readings and settings to some degree. Issues such as precise timing, data correlation, or adding an “accelerator time” timestamp will take more thought and work. • The diversity of EPICS IOC platforms becomes a non-issue with the OAC solution. • Java Channel Access already exists caj.cosylab.com
OAC Details • The map from Acnet device to PV could be easily read from a DB table (or use the Acnet long name). • There is a large diversity of PV fields besides the .VAL value field that would probably not be automatically supported. • EPICS PVs support various data types that would require some diligence by the DABBELer to make sure the mapping is done correctly. • EPICS also has better support for string types than ACNET that might be difficult to support.
OAC Potential Problems • An OAC could do a CA Monitor on a PV when a periodic read request arrives for the device/PV, avoiding too much unnecessary network traffic. • There might be problems with a race condition when reading on events --- which comes first, multicast or IOC post? • an “accelerator time” timestamp might be useful. • What do we do about passive PVs?
OAC Alarms • EPICS supports multiple alarm levels that ACNET doesn’t support. Some mapping would have to be created. • OAC could detect which of its Acnet devices have alarm blocks, and if the corresponding PV has alarm information, then the OAC can set up a monitor on the PV alarm to set the Acnet device alarm info.
OAC Misc • It would be nice to generate the DABBEL info automatically from the PV databases. • It will be necessary to enumerate a list of limitations or choices that were made so that every one knows the rules, i.e. in how alarm level mapping is done, or in supporting (or not) various PV fields and data types.
EPICS-Acnet Opinions • Is this a solution looking for a problem or just a longer term problem? We don’t really have many VME/vxWorks Epics IOCs.: SNS LLRF (going away), and klystron interlocks (easily converted to MOOC). • We have several soft IOCs which are mostly easily converted to ACNET std. front-ends or OACS: GPIB, multiple PLCs, HINS Modulator, PID loops.