A Next Generation OCS

OCS&

A Next Generation OCS

What is Ethernet/IP?• Open Network

specified by ODVA• Uses standard

Ethernet components• Based on CIP -

Common Industrial Protocol

• Allen-Bradley’s bet for the future

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A Next Generation OCS

Ethernet/IP Messaging Basics• Explicit (Class 3) Messaging

• Uses TCP/IP• Follows a Client/Server Model• Intended for occasional data reading/writing

• Implicit (Class 1) Messaging• Sometimes called I/O Messaging• Uses UDP/IP• Follows a Producer/Consumer Model• Can be Multicast• Designed for continuous type data exchange

A Next Generation OCS

Does OCS Do Ethernet/IP?• The OCS has an embedded

Ethernet/IP Driver in all models with “full” Ethernet functionality• NX, QX (also SVGA OCS,

ETN200/300)• This implementation is well-defined,

but not well understood (SUP740 - Ethernet Supplement)

• The INTENTION of the OCS Ethernet/IP implementation is to allow an OCS/RCS to act as an I/O Drop on an Ethernet/IP Network

• Additional functionality will be added to the OCS’ Ethernet/IP capability in 2008

A Next Generation OCS

How Do I Setup OCS/RCS with an Ethernet/IP I/O Connection?• Select Ethernet/IP Checkbox in Cscape• Select Size and Location of Produced

and Consumed Data (up to 256bytes)• Assign 16-bit Status Register

SLC 5/05PLC-5E

ControlLogix

NX OCSCompactLogix

A Next Generation OCS

What’s Involved on the A-B side?• The appropriate A-B software

configuration tool must be used (ie RSLogix 5000)

• The goal is to setup an I/O Data Connection between the PLC and the OCS/RCS• Used to transfer data between a PLC

and a field device (OCS/RCS)• PLC is the “Originator”• I/O Device (OCS/RCS) is the “Target”• PLC Input flows T>O• PLC Output flows O>T• Target Device must be present in the

PLC’s I/O tree

A Next Generation OCS

RSLogix 5000 Configuration• From the Controller

Properties pane, add a new Ethernet “Module” into the I/O tree

• Point to I/O Configuration, Right-click and select “Add Module”. Select the interface module (eg 1756-ENBT or 1756-ENET/B) and apply changes

• Point to the EIP interface module, right click and select “Insert Module” and choose “ETHERNET MODULE - Generic Ethernet Module”

A Next Generation OCS

RSLogix 5000 Configuration

• Select the Module Properties tag• Input Assembly Instance and Size. This is for data

produced by the OCS. Set this to 100. Set the size to the same number of bytes produced by the OCS

• Output Assembly Instance and Size. This is for data consumed by the OCS. Set this to 101.

• Configuration Assembly Instance and Size. Set the size to 0.

• Select the Module Properties tag and configure the following:• Name. This will also be

used as the tag. An example is “NXOCS”.

• COMM Format. The OCS supports INT, DINT, REAL

• IP Address

A Next Generation OCS

Tag Creation

• Select the Module Properties tag• The ‘:O’ tag is the PLC output data consumed by the

OCS.• The ‘:I’ tag is the PLC input data produced by the

OCS.• the ‘:S’ tag (if created) is unused with the OCS

• Tags associated with the OCS will be inserted into the ControlLogix’ I/O tree after the completion of the module selection and configuration process

• The tag name is the same name given to the module in the module properties screen

Example Tags:

NXOCS:I.Data[0]NXOCS:I.Data[1]

...NXOCS:I.Data[127]