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The CNOE-311 is an Ethernet option module for Schneider Automation's TSX Compact PLC. The CNOE-311 includes an LCD screen and 5-button keypad which simplifies basic configuration such as setting the IP Address. The LCD also provides the ability to display status messages, Ethernet and backplane statistics, and firmware revisions.

This module is a drop-in replacement for the Niobrara CNOE-211.


The single 10/100BaseT RJ45 Ethernet port is Modbus/TCP compatible.

  • The PLC can issue 0x, 1x, 3x, and 4x MSTR reads over Ethernet.
  • The PLC can issue 0x and 4x MSTR writes over Ethernet.
  • A PC can program the PLC via Ethernet.
  • Any Modbus/TCP compatible device can read/write the PLC via Ethernet.
  • PLC peer-to-peer communications over Modbus/TCP Ethernet.
  • I/O Ethernet scanning.

The Ethernet port of the CNOE-311 is also SY/MAX 802.3 compatible, which enables:

  • The PLC to read or write SY/MAX registers over Ethernet.
    • Including SY/MAX 450 and 650 PLCs directly.
    • Including other SY/MAX and PowerLogic equipment through NR&D network products.
  • Any SY/MAX 802.3 compatible device to read/write PLC registers.
  • Modbus/TCP <> SY/MAX 802.3 bridging without PLC intervention.


  • TSX Compact PLC (-258, -265, -275, -285 only).
  • Free slot in the main rack (slots 3, 4, or 5).
  • Compact PLC Executive version 2.07 or greater. The Compact executive required for the CNOE-311 is now available at Schneider Automation's website.


IP configuration can occur from the front panel using the LCD and keypad, over Ethernet via BOOTP or DHCP, or from the PLC via MSTR or conifg extensions*. Multiple CNOEs can work in a single local PLC rack. No web pages are served by this module. Modules come with a user manual and configuration software on CD, 1-year warranty and 1-year free firmware upgrades.


The CNOE-311 is available as: CNOE-311 with one 100BaseT Ethernet port

* Contact Schneider Automation for programming software that supports Ethernet configuration extensions for the Compact PLC.

Effective 26 March 2008 - Specifications subject to change without notice.