Interfacing EPICS IOCs With Allen Bradley PLCs ApplicationsApplications Recent enhancementsRecent enhancements Backwards compatibilityBackwards compatibility ReliabilityReliability

EPICS device and driver support for Allen Bradley DF1 protocol Originally written for (and funded by) the KECK observatoryOriginally written for (and funded by) the KECK observatory Recently updated for APT high power RF and personnel safety subsystemsRecently updated for APT high power RF and personnel safety subsystems

DF1 Driver Applications IOC host architecture neutralIOC host architecture neutral –runs on PC, VME, and VXI IOCs Point to point serial communicationPoint to point serial communication Allen Bradley Data Highway communicationAllen Bradley Data Highway communication –Allen Bradley KF2 standalone –Data Link DL PC low cost ISA card

Recent Enhancements Support for Allan Bradley PLC5 architectureSupport for Allan Bradley PLC5 architecture Output trackingOutput tracking DF1 serverDF1 server OthersOthers

Support for Allan Bradley PLC5 architecture PLC5 addressingPLC5 addressing –Thanks to Eric Bjorklund for improved ASCII address parser PLC5 protocolPLC5 protocol –Data type safe R/W –Elements in files Improved access control granularityImproved access control granularity

Output Tracking IOC initialization does not block for Initial output value query completionIOC initialization does not block for Initial output value query completion –Output records in invalid / undefined alarm state until this query completes Output records track changes occurring in PLC (they are processed)Output records track changes occurring in PLC (they are processed) –Potential side effects when output records have forward links

DF1 server Allan Bradley PLCs see EPICS records as elements in files in a PLC5 on DH+Allan Bradley PLCs see EPICS records as elements in files in a PLC5 on DH+ Reduced latencyReduced latency Occurs when record addresses data highway node number of IOCOccurs when record addresses data highway node number of IOC

Other Enhancements Specification of independent scan rate for each PLC5 fileSpecification of independent scan rate for each PLC5 file Each serial link or Data Highway may be assigned a different local node addressEach serial link or Data Highway may be assigned a different local node address “drvSerial” does not delete tasks when a link drops out“drvSerial” does not delete tasks when a link drops out

Backward compatibility Continue to support original addressing and protocol of older PLCsContinue to support original addressing and protocol of older PLCs –additional testing required for this version Driver no-longer aborts a write in the queue so that it can be combined with another subsequent writeDriver no-longer aborts a write in the queue so that it can be combined with another subsequent write

Reliability This driver has been supporting the APT high level RF and window test systems since the beginning of the calendar yearThis driver has been supporting the APT high level RF and window test systems since the beginning of the calendar year The driver has been very reliable on this very lightly loaded PLC5 systemThe driver has been very reliable on this very lightly loaded PLC5 system Now have operational experience with Allen Bradley Data HighwayNow have operational experience with Allen Bradley Data Highway

Getting a copy of the DF1 protocol driver described here KECK (Allan Honey) is the distribution point but I have not yet sent them a copy of this versionKECK (Allan Honey) is the distribution point but I have not yet sent them a copy of this version

In Memory Communication with VME Resident Allen Bradley PLC5? Contact Eric Bjorklund (LANL LANSCE-6) for his driverContact Eric Bjorklund (LANL LANSCE-6) for his driver Both the DF1 driver (described here) and Eric’s VME driver use the same common PLC5 enhanced device supportBoth the DF1 driver (described here) and Eric’s VME driver use the same common PLC5 enhanced device support

Conclusions The Allen Bradley DF1 device / driver support has been upgraded to support PLC5s, output tracking, and DF1 server operation.The Allen Bradley DF1 device / driver support has been upgraded to support PLC5s, output tracking, and DF1 server operation. It has been very reliable under continuous production, but lightly loaded, operation of the APT high power RF system.It has been very reliable under continuous production, but lightly loaded, operation of the APT high power RF system.