Ethernet/IP Driver

Ethernet/IP is used to communicate with multiple generations and families of Rockwell Automation / Allen Bradley PLCs. The name can be confusing, and actually stands for [Common] Industrial Protocol over Ethernet. It is an application layer protocol, layered on top of standard TCP/IP networking.

There are two distinct families of PLCs with which this driver can be used, and they have significant operational differences. The newer devices such as ControlLogix, CompactLogix, and FlexLogix PLCs implement native CIP Protocol. This allows reads and writes using the actual tag-names from the PLC, complex tag structuring, and grouping of unrelated tags in a single message.

The older devices such as PLC5, SLC5, and MicroLogix implement PCCC/DF1 protocol, encapsulated in Ethernet/IP. These devices group their tags into very specific categories of File, Instance, and SubElement. Only requests for items within the same file can be grouped in a given request.

  • Uses standard Ethernet networking hardware

  • The WinCC OA system is always the master and initiates all connections and transactions

  • Through-routing to remote PLCs without an Ethernet connection is only supported for transparent interfaces such as the 1761-NET-ENI

  • Supports WinCC OA Redundancy

  • Supports redundant connection to PLC

  • Supported devices include the following:

PLC Series Model Used Protocol Interface
ControlLogix Native EIP CPU Direct 1756-ENBT 1756-ENET/B 1756-EN2T
CompactLogix

1769-L32E

1769-L35E

 Native EIP CPU Direct
Other models Native EIP

1768-ENBT

1761-NET-ENI
FlexLogix

1794-L34

1794-L33

Other models

 Native EIP

1788

1761-NET-ENI
Omron CJ2 CJ2M Native EIP CJ2M-CPU32
PLC5E - PCCC CPU Direct
PLC5E PLC5C - PCCC

1785-ENET

1761-NET-ENI
SLC500 SLC 5/05 PCCC CPU Direct

SLC 5/04

SLC 5/03

 PCCC 1761-NET-ENI
MicroLogix

MicroLogix 1100

MicroLogix 1400

 PCCC CPU Direct

MicroLogix 1100

MicroLogix 1200

MicroLogix 1500

 PCCC 1761-NET-ENI
Note:

  • Some older devices may require firmware updates if they were not previously being used with Ethernet/IP.

  • The 1761-NET-ENI bridges to a PLC’s serial port, so compared to direct Ethernet, throughput will be reduced.

  • ControlLogix processors with firmware V20 or higher support read-by-id mode for most tag types. Older firmware requires always reading by name.

  • Newer Ethernet adapters such as the 1756-EN2T support message-sizes up to 2048 bytes. Older adapters require using the original 500-byte message size.

  • Omron PLCs support messages with a size of up to 1992 bytes.

Other models supporting native EIP should work if they have a built-in Ethernet port or an Ethernet interface card but no guarantee can be given.

Other models supporting PCCC should work if they have a built-in Ethernet port supporting EIP encapsulation, or through a transparent Ethernet to serial bridge such as a 1761-NET-ENI, but no guarantee can be given.