1. Berliner Elektronenspeicherringgesellschaft für Synchrotronstrahlung mbH (BESSY) OPC - Device Support Bernhard Kuner, Carsten Winkler BESSY, Berlin, Germany

2. Kuner, Winkler: OPC Device Support – EPICS Collaboration Meeting at Diamond, June 2003 Introduction to OPC OPC: OLE (COM) for process control DCOM: Distributed Component Object Model Client/Server scalable and distributed over network “Data Access” specification read/write, time stamps, quality polled or callback “Alarm and Event” specification Existing OPC servers support only a subset of the defined OPC features

3. Kuner, Winkler: OPC Device Support – EPICS Collaboration Meeting at Diamond, June 2003 Data Flow Device - OPC server communication: proprietary, vendor dependant OPC client - OPC server communication: via DCOM (Microsoft) OPC libraries available for: all Windows, Unix, not vxWorks

4. Kuner, Winkler: OPC Device Support – EPICS Collaboration Meeting at Diamond, June 2003 Client Data Access Connect to server Client will start/stop the server Add group Client defines groups with common parameters for all items within the group Add items Client subscribes for several data objects

5. Kuner, Winkler: OPC Device Support – EPICS Collaboration Meeting at Diamond, June 2003 Bessy Installation Connect PLC controlled beamlines to EPICS - 30 PLCs: c. 6,000 PVs - 4 OPC servers -Currently 600 PVs with the new iocShell -In the future: 30,000 PVs Data volume One PLC: 6 kB/s, polled with 50 ms - > 2 GB/d raw data over the network - > 200 kB Channel Access data

6. Kuner, Winkler: OPC Device Support – EPICS Collaboration Meeting at Diamond, June 2003 Former Approaches OPC_CAS –Doesn’t work reliably –Several crashes a day VisualBasic program with Kepware OPC client and ActiveX_CAS -Proper handling of values, alarms and graphic limits -Crashes ALH and other clients -No access security -OPC can’t set STAT and SEVR XCas –Another CAS based solution

7. Kuner, Winkler: OPC Device Support – EPICS Collaboration Meeting at Diamond, June 2003 Device Support for EPICS 3.14 For these record types: - ai, ao - bi, bo - mbbi, mbbo - mbbiDirect, mbboDirect - longin, longout - stringin, stringout - (waveform) OPC client with - Softing OPC Toolbox 3.01 - Other client libraries possible

8. Kuner, Winkler: OPC Device Support – EPICS Collaboration Meeting at Diamond, June 2003 opcDevSup Features Data conversion for all integer and float data types Timestamp generated by OPC server or EPICS determined by the record‘s TSE field Map OPC quality to records STAT/SEVR fields Out records may be written by the PLC and by EPICS in - records: read only records out - records: read/write records Record processing: SCAN field: „I/O Intr“ or „.1 second“ to „10 second“ OUT records are not „Passive“, but „I/O Intr“

9. Kuner, Winkler: OPC Device Support – EPICS Collaboration Meeting at Diamond, June 2003 Conclusions Portable CAS solutions never satisfy EPICS clients. For full range of EPICS functionality EPICS records are required.