Ether ip epics ethernet ip support for controllogix
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ether_ip - EPICS EtherNet/IP support for ControlLogix. Kay-Uwe Kasemir, LANL Nov. 2000. EtherNet/IP. IP = Industrial Protocol Evolved from “ControlNet over EtherNet” SIG Encapsulates CIP in TCP & UDP (Ctrl. & Info. Protocol, shared by DeviceNet and ControlNet) Part of ControlNet Specs:

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ether_ip - EPICS EtherNet/IP support for ControlLogix

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Ether ip epics ethernet ip support for controllogix

ether_ip - EPICS EtherNet/IP support for ControlLogix

Kay-Uwe Kasemir, LANL

Nov. 2000


Ethernet ip

EtherNet/IP

  • IP = Industrial Protocol

  • Evolved from “ControlNet over EtherNet” SIG

  • Encapsulates CIP in TCP & UDP

    • (Ctrl. & Info. Protocol, shared by DeviceNet and ControlNet)

  • Part of ControlNet Specs:

    • Open DeviceNet Vendor Assoc.,http://www.odva.org


Ethernet ip spec details

EtherNet/IP Spec. Details

  • ControlNet Spec.2 Errata 1, E.Net. still in red

  • Open portion of CIP (object & service codes):

    • How to route messages

    • How to read serial number and vendor code

  • Vendor specific:

    • Get data of real interest, e.g. PLC values

  • This driver:CIP Read/WriteData as used byAllen Bradley ControlLogix PLCs

    • Round-trip request/response mechanism

    • Subscription (ForwardOpen) with triggered updates via UDP not implemented/documented by AllenBradley


Epics driver device

EPICS Driver/Device

  • No special hardware, neither for setup nor runtime

  • IOCs (pc486, PPC), command-line (Win32, Unix)

  • Can read & write any tag on PLC

    • DTYP=“EtherIP”, [email protected] PS1RB2”

    • also: [email protected] arraytag[21]”, [email protected] struct.elem”

    • REAL, INT, DINT, BOOL,scalars, struct. elements, arrays

    • no need to “publish” tag in PLC’s LadderLogic or program ControlNet connection to allocate bandwidth

    • Records: ai, ao, bi, bo, mbbi, mbbo, mbbiDirect, mbboDirect

  • INP/OUT can be changed at runtime to use different tag on different PLC!

  • Handles disconnects/reconnects (e.g. PLC reboot)


Driver device details

Driver/Device Details

  • One communication thread per PLC

  • Combines requests to minimize transfers

    • (up to ~500 byte PLC buffer limit)

  • Arrays are transferred as a whole (default)

  • Output records:

    • Monitors PLC, updates rec. on change

  • Supports SCAN=I/O Event (also for e.g. 30Hz scans)

  • Provides statistics: min/max/last scan times, #errors, ...

  • Performance: about 8ms per transfer

    • Single REAL tag: 8ms

    • BOOL[352]: 8ms

    • 3xREAL[30]: ~20ms (combined requests)


Conclusion

Conclusion

  • Setup:

    • No additional hardware (neither for PC, IOC, nor communication setup)

  • Use:

    • No special LadderLogic required, though arrays might be preferred (performance)

    • Good IOC support (I/O Event, runtime change)

  • Performance:

    • 8ms/transfer, susceptible to network delays

    • good enough for most applications?


Ether ip epics ethernet ip support for controllogix

Taken after about 46000 runs,

PPC IOC, 350 BI @10Hz, 150 AI @ 1Hz, switched network.

After 1 week: max. scan time 0.15 sec

Test


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