Technical Data · Publication 1756-TD003 · Rockwell Automation

1756 ControlLogix Communication Modules Specifications

This technical data sheet covers specifications for the 1756 ControlLogix communication module family, published March 2022. It documents electrical, environmental, and connection specifications for modules spanning EtherNet/IP, ControlNet, DeviceNet, DH+, Remote I/O, DH-485, and SynchLink networks. Catalog numbers include standard, conformal coated (K suffix), and extended environment (XT suffix) variants. Engineers use this document to select and specify modules for ControlLogix chassis installations.

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1000 Max CIP I/O Connections
50,000 packets/sec Max I/O Packet Rate
256 axes Max Integrated Motion Axes
-25…+70 Operating Temp, XT Modules

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Specifications

EtherNet/IP Connection Specifications

1756-ENBT, TCP / CIP Connections 64 TCP / 128 CIP
1756-EN2F/EN2T/EN2TP/EN2TR/EN3TR, TCP / CIP Connections 128 TCP / 256 CIP
1756-EN4TR, TCP Connections 512 TCP
1756-EN4TR, CIP Connections 1000 I/O + 528 messaging
1756-EN4TR, Max I/O Packet Rate (no CIP Security) 50,000 packets/sec
1756-EN4TR, Max I/O Packet Rate (with CIP Security integrity) 25,000 packets/sec
1756-EN4TR, Max I/O Packet Rate (integrity + confidentiality) 15,000 packets/sec
1756-EN2F/EN2T Communication Rate 100 Mbps (no auto-negotiation) for EN2F; 10/100 Mbps for EN2T
1756-EN4TR Communication Rate 10/100 Mbps and 1 Gbps

EtherNet/IP Module Technical Specifications

1756-EN2F Current Draw @ 5.1V DC 1.2 A
1756-EN2T/EN2TR/EN2TP/EN3TR Current Draw @ 5.1V DC 1 A
1756-EN4TR Current Draw @ 5.1V DC 1.2 A
1756-EN2F Power Dissipation 6.2 W
1756-EN2T/EN2TR/EN2TP/EN3TR Power Dissipation 5.1 W
1756-EN4TR Power Dissipation 6.12 W
Slot Width (all modules) 1
Module Location Chassis-based, any slot
Compatible Chassis 1756-A4, 1756-A7, 1756-A10, 1756-A13, 1756-A17
USB Port USB full speed (12 Mbps), temporary local programming only

EtherNet/IP Environmental Specifications

Operating Temperature (standard modules) 0…60 °C (32…140 °F)
Operating Temperature (XT modules) -25…+70 °C (-13…+158 °F)
Storage Temperature -40…+85 °C (-40…+185 °F)
Relative Humidity 5…95% noncondensing
Vibration (Operating) 2 g @ 10…500 Hz
Shock, Operating 30 g
ESD Immunity 6 kV contact / 8 kV air discharges
Emissions Class A (CISPR 11 / IEC 61000-6-4)

DeviceNet Module (1756-DNB) Specifications

Communication Rates 125 Kbps (500 m max), 250 Kbps (250 m max), 500 Kbps (100 m max)
Number of Nodes, Max 64
Current Draw @ 5.1V DC 400 mA
Power Dissipation 3.5 W
DeviceNet Voltage Range 11…25V DC CL 2/SELV

DH+ and Remote I/O Module Specifications

1756-DHRIO Communication Rate 57.6 Kbps, 115.2 Kbps, 230.4 Kbps
1756-DHRIO Remote I/O Scanner only; 32 logical rack connections per channel; 16 block transfer connections per channel
1756-RIO Remote I/O Scanner or adapter; 32 physical racks (0…76)
1756-DHRIO Current Draw @ 5.1V DC 850 mA
1756-RIO Current Draw @ 5.1V DC 450 mA
1756-DHRIO Ports 2, individually selectable for DH+ or remote I/O

ControlNet Module Specifications

ControlNet Communication Rate 5 Mbps
1756-CN2 Logix Connections 128
1756-CNB Logix Connections 40…48
Number of Nodes, Max 99
1756-CN2 Current Draw @ 5.1V DC 1100 mA
1756-CN2R Current Draw @ 5.1V DC 1300 mA

SynchLink Module (1756-SYNCH) Specifications

SynchLink Data Rate 5 Mbps
Operating Wavelength 650 nm (red)
Type of Communication Synchronous
Frame Period 50 µs
Cable Fiber Type 200/230 micron HCS (Hard Clad Silica)
Cable Length 1…300 m (3.28…984.2 ft)
Current Draw @ 5.1V DC 1200 mA

Communication Protocols

Supported industrial networks and field buses for the products covered by this publication.

EtherNet/IP Supported by 1756-EN2F, 1756-EN2T, 1756-EN2TP, 1756-EN2TR, 1756-EN3TR, 1756-EN4TR, 1756-ENBT, and XT/K variants. Supports DLR, PRP (EN2TP and EN4TR with firmware 4.001+), redundant adapters, and CIP Security (EN4TR). ControlNet Supported by 1756-CN2, 1756-CN2R, 1756-CNB, 1756-CNBR, 1756-CN2RXT. 5 Mbps, up to 99 nodes. Considered a legacy network per the publication. DeviceNet Supported by 1756-DNB. 125/250/500 Kbps, up to 64 nodes. Uses Common Industrial Protocol (CIP). Data Highway Plus (DH+) Supported by 1756-DHRIO and 1756-DHRIOXT. 57.6, 115.2, or 230.4 Kbps. Two ports individually selectable for DH+ or remote I/O. Remote I/O Supported by 1756-DHRIO (scanner only) and 1756-RIO (scanner or adapter). When 1756-RIO is used as an adapter, the chassis must include a ControlLogix controller. DH-485 Supported by 1756-DH485 at 9600 bps or 19.2 Kbps. SynchLink Supported by 1756-SYNCH. 5 Mbps fiber-optic synchronous link for coordinated motion and drive control across ControlLogix chassis.

Certifications & Compliance

c-UL-us: UL Listed Industrial Control Equipment (UL File E65584); UL Listed Class I, Division 2 Group A,B,C,D Hazardous Locations (UL File E194810) CSA: CSA Certified Process Control Equipment (CSA File LR54689C); Class I, Division 2 Group A,B,C,D Hazardous Locations (CSA File LR69960C) CE: EU 2004/108/IEC EMC Directive, EN 61326-1, EN 61000-6-2, EN 61000-6-4, EN 61131-2 ATEX: EU 94/9/EC ATEX Directive, EN 60079-15, EN 60079-0; II 3 G Ex nA IIC T4 Gc X (standard modules); EU 2014/34/EU ATEX Directive, EN IEC 60079-0, EN 60079-7; II 3 G Ex EC IIC T4 Gc (1756-EN4TR) IECEx: IEC 60079-0, IEC 60079-15, II 3 G Ex nA IIC T4 Gc (select modules); IEC 60079-0, 60079-7, II 3 G Ex EC IIC T4 Gc (1756-EN4TR, IECExUL 18.0130X) FM: FM Approved Equipment for Class I Division 2 Group A,B,C,D Hazardous Locations RCM: Australian Radiocommunications Act, compliant with EN 61000-6-4 KC: Korean Registration of Broadcasting and Communications Equipment, Article 58-2 of Radio Waves Act, Clause 3 EAC: Russian Customs Union TR CU 020/2011 EMC and TR CU 004/2011 LV Technical Regulations EtherNet/IP: ODVA conformance tested to EtherNet/IP specifications DeviceNet: ODVA conformance tested to DeviceNet specifications CI: ControlNet International conformance tested to ControlNet specifications

Document Contents

Full PDF covers the following topics in detail:

  • Summary of Changes
  • Available Communication Modules
  • EtherNet/IP Network, module selection guide and connection specifications
  • EtherNet/IP Network Specifications, Tables 1–6: connections, data, packet rates, technical specs, environmental specs, certifications
  • EtherNet/IP-XT Module Specifications, Tables 7–9: technical specs, environmental specs, certifications
  • EtherNet/IP Module Diagrams (1756-EN2T, EN2TP, EN2TR, EN3TR, EN2F, EN4TR)
  • Accessories, Ethernet Network
  • DeviceNet Network, Tables 10–12: technical specs, environmental specs, certifications
  • Accessories, DeviceNet Network
  • DH+ and Remote I/O Networks, Tables 13–18: technical specs, environmental specs, certifications (standard and XT modules)
  • Accessories, DH+ and Remote I/O Networks
  • DH-485 Network, Tables 19–21: technical specs, environmental specs, certifications
  • Accessories, DH-485 Network
  • SynchLink Communication, Tables 22–24: technical specs, environmental specs, certifications
  • Accessories, SynchLink Network
  • ControlNet Network, Tables 25–30: technical specs, environmental specs, certifications (standard and XT modules)
  • ControlNet Module Diagrams (1756-CN2, CN2R)
  • Accessories, ControlNet Network
  • Legacy Modules, 1756-EWEB (End of Life) and 1756-TIME (End of Life) specifications
  • Additional Resources

In-Stock Products Covered by This Document

Every product below is in stock at our Charlotte, NC warehouse and covered by this publication. Ships same-day (orders before 4 PM ET) with 2.5-year warranty included.

1756-EN2T
1756-EN2T
Allen-Bradley 1756-EN2T ControlLogix Module
$1,508.15
1756-ENBT
1756-ENBT
Allen-Bradley 1756-ENBT ControlLogix Module
$1,357.80

Frequently Asked Questions

Which 1756 EtherNet/IP modules support Parallel Redundancy Protocol (PRP)?
The 1756-EN2TP, 1756-EN2TPK, 1756-EN2TPXT, 1756-EN4TR, 1756-EN4TRK, and 1756-EN4TRXT support PRP. The 1756-EN4TR requires firmware revision 4.001 or higher to enable PRP.
What is the maximum number of CIP connections on the 1756-EN4TR?
The 1756-EN4TR supports 1000 CIP I/O connections and 528 CIP messaging connections. It also supports 512 TCP connections.
What packet rate can the 1756-EN4TR achieve for I/O traffic?
Without CIP Security, the 1756-EN4TR supports up to 50,000 I/O packets per second. With CIP Security integrity enabled, the rate is 25,000 packets per second. With integrity and confidentiality, the rate is 15,000 packets per second.
What operating temperature range do the ControlLogix-XT (extended environment) communication modules support?
The XT modules, including 1756-EN2TXT, 1756-EN2TRXT, 1756-EN2TPXT, 1756-EN4TRXT, 1756-DHRIOXT, and 1756-CN2RXT, operate from -25 to +70 °C (-13 to +158 °F).
Can the 1756-RIO module operate as a remote I/O adapter?
Yes, the 1756-RIO/B can operate as either a remote I/O scanner or a remote I/O adapter. When used as an adapter, the chassis must include a ControlLogix controller.
What is the status of the 1756-EWEB and 1756-TIME modules?
Both modules reached End of Life on November 1, 2021. The publication recommends using a ControlLogix 1756 Compute module (1756-CMS1B1 or 1756-CMS1C1) as an engineered replacement for the 1756-EWEB, and the Aparian Time Sync A-TSM/B module as a replacement for the 1756-TIME.
What integrated motion axis counts are supported by the EtherNet/IP modules?
With a 1756-L8x or 1756-L7x controller, the 1756-EN2F, 1756-EN2T and 1756-EN2TXT support up to 8 axes at firmware revision 3.6 or later, the 1756-EN2TR at 5.x or later, the 1756-EN2TRXT at 5.028 or later, and the 1756-EN2TP and 1756-EN2TPXT at their listed firmware. The 1756-EN3TR supports up to 128 axes. The 1756-EN4TR and 1756-EN4TRXT support up to 256 axes.

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