Installation Instructions

Summary of Changes

This publication contains the following new or updated information. This list includes substantive updates only and is not intended to reflect all changes.

Environment and Enclosure

ATTENTION: This equipment is intended for use in a Pollution Degree 2 industrial environment, in overvoltage Category II applications (as defined in EN/IEC 60664-1), at altitudes up to 2000 m (6562 ft) without derating. This equipment is not intended for use in residential environments and may not provide adequate protection to radio communication services in such environments. This equipment is supplied as open-type equipment for indoor use. It must be mounted within an enclosure that is suitably designed for those specific environmental conditions that will be present and appropriately designed to prevent personal injury resulting from accessibility to live parts. The enclosure must have suitable flame-retardant properties to prevent or minimize the spread of flame, complying with a flame spread rating of 5V A or be approved for the application if nonmetallic. The interior of the enclosure must be accessible only by the use of a tool. Subsequent sections of this publication may contain more information regarding specific enclosure type ratings that are required to comply with certain product safety certifications.

In addition to this publication, see the following:

• Industrial Automation Wiring and Grounding Guidelines, publication 1770-4.1, for additional installation requirements.
• NEMA Standard 250 and EN/IEC 60529, as applicable, for explanations of the degrees of protection provided by enclosures.

WARNING: When you insert or remove the module while backplane power is on, an electrical arc can occur. This could cause an explosion in hazardous location installations. Be sure that power is removed or the area is nonhazardous before proceeding. ⚠️

WARNING: If you connect or disconnect wiring while the field side power is on, an electrical arc can occur. This could cause an explosion in hazardous location installations. Be sure that power is removed or the area is nonhazardous before proceeding. ⚠️

ATTENTION: This product is grounded through the DIN rail to chassis ground. Use zinc plated chromate-passivated steel DIN rail to assure proper grounding. The use of other DIN rail materials (for example, aluminum or plastic) that can corrode, oxidize, or are poor conductors, can result in improper or intermittent grounding. Secure DIN rail to mounting surface approximately every 200 mm (7.8 in.) and use end-anchors appropriately. Be sure to ground the DIN rail properly. See the Industrial Automation Wiring and Grounding Guidelines, Rockwell Automation publication 1770-4.1, for more information.

ATTENTION: Preventing Electrostatic Discharge
This equipment is sensitive to electrostatic discharge, which can cause internal damage and affect normal operation. Follow these guidelines when you handle this equipment:

• Touch a grounded object to discharge potential static.
• Wear an approved grounding wriststrap.
• Do not touch connectors or pins on component boards.
• Do not touch circuit components inside the equipment.
• If available, use a static-safe workstation.

UK and European Hazardous Location Approval

The following analog input/output modules are European Zone 2 approved: 1794-IE8, 1794-OE4, and 1794-IE4XOE2, Series B.

The following applies to products marked II 3 G:

• Are Equipment Group II, Equipment Category 3, and comply with the Essential Health and Safety Requirements relating to the design and construction of such equipment given in Schedule 1 of UKEX and Annex II of EU Directive 2014/34/EU. See the UKEx and EU Declaration of Conformity at rok.auto/certifications for details.
• The type of protection is Ex ec IIC T4 Gc (1794 IE8) according to EN IEC 60079-0:2018 and EN IEC 60079-7:2015+A1:2018.
• The type of protection is Ex nA IIC T4 Gc (1794-OE4 and 1794-IE4XOE2) according to EN 60079-0:2009 & EN 60079-15:2010.
• Comply to Standard EN IEC 60079-0:2018 & EN IEC 60079-7:2015+A1:2018 reference certificate number DEMKO 14 ATEX 1342501X and UL22UKEX2378X.
• Comply to Standards: EN 60079-0:2009, EN 60079-15:2010, reference certificate number LCIE 01ATEX6020X.
• Are intended for use in areas in which explosive atmospheres caused by gases, vapors, mists, or air are unlikely to occur, or are likely to occur only infrequently and for short periods. Such locations correspond to Zone 2 classification according to UKEX regulation 2016 No. 1107 and ATEX directive 2014/34/EU.

IEC Hazardous Location Approval

The following applies to products marked with IECEx certification (1794-IE8):

• Are intended for use in areas in which explosive atmospheres caused by gases, vapors, mists, or air are unlikely to occur, or are likely to occur only infrequently and for short periods. Such locations correspond to Zone 2 classification to IEC 60079-0.
• The type of protection is Ex ec IIC T4 Gc according to IEC 60079-0 and IEC 60079-7.
• Comply to Standards IEC 60079-0, Explosive atmospheres Part 0: Equipment - General requirements, Edition 7, Revision Date 2017, IEC 60079-7, 5.1 Edition revision date 2017, Explosive atmospheres - Part 7: Equipment protection by increased safety "e", reference IECEx certificate number IECEx UL 14.0066X.

Installing Your Analog Input/Output Module

The FLEX™ I/O Input, Output and Input/Output Analog module mounts on a 1794 terminal base.

ATTENTION: During mounting of all devices, be sure that all debris (metal chips, wire strands, etc.) is kept from falling into the module. Debris that falls into the module could cause damage on power up. ⚠️

Diagram showing a FLEX I/O module mounting onto a terminal base. Numbered components include: 1. Keyswitch, 2. Terminal base, 3. Flexbus connector, 4. Module, 5. Alignment bar, 6. Groove on terminal base, 7. Latching mechanism.

1. Rotate the keyswitch (1) on the terminal base (2) clockwise to position 3 (1794-IE8), 4 (1794-OE4) or 5 (1794-IE4XOE2) as required.
2. Make certain the Flexbus connector (3) is pushed all the way to the left to connect with the neighboring terminal base or adapter. You cannot install the module unless the connector is fully extended.
3. Make sure the pins on the bottom of the module are straight so they will align properly with the connector in the terminal base.
4. Position the module (4) with its alignment bar (5) aligned with the groove (6) on the terminal base.
5. Press firmly and evenly to seat the module in the terminal base unit. The module is seated when the latching mechanism (7) is locked into the module.

Connecting Wiring for the Analog Inputs and Outputs

Connect individual input/output wiring to numbered terminals on the 0-15 row (A) for 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3T, and 1794-TB3TS, or on row (B) for the 1794-TBN as indicated in Table 1, Table 2, and Table 3.

IMPORTANT: Use Belden 8761 cable for signal wiring.

Connect channel common/return to the associated terminal on row (A) or row (B) for the 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3T, and 1794-TB3TS, or on row C for the 1794-TBN. For input devices requiring terminal base power, connect the channel power wiring to the associated terminal on row (C).

Connect any signal wiring shields to functional ground as near as possible to the module. 1794-TB3T or 1794-TB3TS only: Connect to earth ground terminals C-39...C-46.

Connect the +V DC power to terminal 34 on the 34-51 row (C) and -V common/return to terminal 16 on the B row.

ATTENTION: To reduce susceptibility to noise, power analog modules and digital modules from separate power supplies. Do not exceed a length of 9.8 ft (3 m) for DC power cabling. ⚠️

If daisychaining +V power to the next terminal base, connect a jumper from terminal 51 (+V DC) on this base unit to terminal 34 on the next base unit.

If continuing DC common (-V) to the next base unit, connect a jumper from terminal 33 (common) on this base unit to terminal 16 on the next base unit.

Table 1 - Wiring Connections for the 1794-IE8 Analog Input Modules

(1) Use when transmitter requires terminal base power.

Terminal Base Wiring for the 1794-IE8

Terminal base wiring diagram for 1794-IE8. It shows terminal rows A (0-15 Input), B (16-33 24V Common), and C (34-51 24V Power). Various connection types are illustrated: AC or DC 4-Wire Current Transmitter (External power), AC or DC 4-Wire Voltage Transmitter (External power), 3-Wire Transmitter (Terminal base powered), and 2-Wire Current Transmitter (Terminal base powered loop).

(1) 1, 3, 5, 7, 9, 11, 13, and 15 are internally connected in the module to 24V DC common.

(2) 1, 3, 5, 7, 9, 11, 13, and 15 are internally connected in the module to 24V DC common.

Terminal Base Wiring for the 1794-OE4

Terminal base wiring diagram for 1794-OE4. It shows terminal rows B (16, 0, 2, 4, 6, 8, 10, 12, 14, 33) and C (34, 1, 3, 5, 7, 9, 11, 13, 15, 51). Connection types include: Current Output Device, Voltage Output Device, Current only 2-Wire Output Device, DC only 3-Wire Output Device.

(1) 1, 3, 5, 7, 9, 11, 13, and 15 are internally connected in the module to 24V DC common.

(2) 1, 3, 5, 7, 9, 11, 13, and 15 are internally connected in the module to 24V DC common.

Table 3 - Wiring Connections for the 1794-IE4XOE2 4-Input 2-Output Analog Module

(1) A-9, 11, 13 and 15 are internally connected in the module to 24V DC common.

(2) Use when transmitter requires terminal base power.

Terminal Base Wiring for the 1794-IE4XOE2

Terminal base wiring diagram for 1794-IE4XOE2. It shows terminal rows A (0-15), B (16-33), and C (34-51). Connection types include: Current Input, Voltage Input, AC or DC 4-Wire Current Transmitter, DC only 3-Wire Transmitter, Current Output Device, Voltage Output Device, Current only 2-Wire Output Device, DC only 3-Wire Output Device.

Specifications

Input Specifications

(1) Includes offset, gain, nonlinearity, and repeatability error terms.

Output Specifications

(1) Includes offset, gain, nonlinearity, and repeatability error terms.

General Specifications

General Specifications for 1794-IE8, 1794-OE4, and 1794-IE4XOE2

Environmental Specifications

(1) You use this category information for planning conductor routing as described in the Industrial Automation Wiring and Grounding Guidelines, Rockwell Automation publication 1770-4.1.

Certifications

(1) See the Product Certification link at rok.auto/certifications for Declaration of Conformity, Certificates, and other certification details.

Rockwell Automation Support

Use these resources to access support information.

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Waste Electrical and Electronic Equipment (WEEE)

At the end of life, this equipment should be collected separately from any unsorted municipal waste.

Rockwell Automation maintains current product environmental compliance information on its website at rok.auto/pec.

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Publication 1794-IN100C-EN-P - October 2022 | Supersedes Publication 1794-IN100B-EN-P - June 2004

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