Product Overview

The 1794-IF4I belongs to the Flex I/O family for distributed analog measurement. Each of its four channels provides individual isolation for signal integrity. This design prevents ground loops and protects your control system. The module arrives factory-calibrated and supports field recalibration when needed. A bi-color status LED indicates module health and configuration mode.

Technical Specifications

The 1794-IF4I offers flexible input configuration with excellent resolution.

• Manufacturer: Rockwell Automation / Allen-Bradley

• Part Number: 1794-IF4I

• Number of Inputs: 4 differential-ended isolated channels

• Conversion Type: Sigma-Delta

• Resolution: 16 bits unipolar, 15 bits plus sign bipolar

• Flexbus Current: 50 mA at 5 VDC

• External DC Power Supply: 24 VDC nominal (19.2 to 31.2 VDC range)

Configurable Input Ranges

Voltage Signals (User Configurable):

• ±10 VDC

• 0 to 10 VDC

• ±5 VDC

• 0 to 5 VDC

Current Signals (User Configurable):

• 4 to 20 mA

• 0 to 20 mA

• ±20 mA

Resolution Details

• Voltage Unipolar: 0.156 mV per count

• Voltage Bipolar: 0.313 mV per count

• Current Unipolar: 0.320 µA per count

• Current Bipolar: 0.640 µA per count

Accuracy and Performance

• Absolute Accuracy: 0.1% full scale at 25°C (voltage and current)

• Voltage Accuracy Drift: 0.0028% full scale per °C

• Current Accuracy Drift: 0.0038% full scale per °C

• Input Conversion Rate: 2.5 to 7.5 milliseconds for all channels

• Common Mode Rejection: High due to isolated design

Power and Thermal Data

• External DC Supply Current: 80 mA at 24 VDC

• Maximum Power Dissipation: 2.0 Watts at 31.2 VDC

• Maximum Thermal Dissipation: 6.8 BTU/hr at 31.2 VDC

Environmental and Physical Ratings

• Operating Temperature: 0 to 55 °C (32 to 131 °F)

• Storage Temperature: -40 to 85 °C (-40 to 185 °F)

• Relative Humidity: 5 to 95% non-condensing

• Vibration Resistance: 5G at 10 to 500 Hz

• Operating Shock: 30G

• Non-Operating Shock: 50G

• Enclosure Type: Open

• Mounting: DIN rail or panel

Isolation Voltage (Depends on Terminal Base)

• With 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3T, 1794-TB3TS : 120 Volts continuous

• With 1794-TBN base unit: 250 Volts continuous

Status Indicators

• OK Status LED (Bi-color):

  • Flashing green: Power-up reset, 24VDC off, or configuration mode

  • Solid red: Module failed initial hardware test

Compatible Terminal Bases

The 1794-IF4I works with these terminal base units:

• 1794-TB2

• 1794-TB3

• 1794-TB3S

• 1794-TB3T

• 1794-TB3TS

• 1794-TBN

Installation Guidance

Follow these steps to install the 1794-IF4I correctly.

1. Mount the Terminal Base: Secure a compatible base like 1794-TB3 onto a DIN rail.

2. Connect External 24VDC Supply: Provide 19.2 to 31.2 VDC to the base terminals.

3. Wire Analog Sensors: Connect 4-20mA transmitters or voltage devices per channel.

4. Insert the Module: Press the 1794-IF4I firmly into the terminal base until latched.

5. Attach the Adapter: Connect a communication adapter like 1794-AENT on the left.

6. Configure Input Ranges: Set each channel for current or voltage using your software.

7. Verify Operation: Check the OK LED shows steady green after configuration.

The 1794-IF4I uses sigma-delta conversion for high noise rejection. The module supports update rates of 2.5 ms, 5.0 ms, or 7.5 ms. Step response varies with the selected conversion rate.

Package Contents

• One (1) Allen-Bradley 1794-IF4I Isolated Analog Input Module

• Installation instructions quick reference guide

Frequently Asked Questions (FAQ)

1. What input signal types does the 1794-IF4I support?
The 1794-IF4I supports 4-20mA, 0-20mA, ±20mA, ±10V, 0-10V, ±5V, and 0-5V. Each of the four channels is user-configurable for current or voltage.

2. Does the 1794-IF4I provide channel-to-channel isolation?
Yes, the 1794-IF4I has individually isolated channels. Isolation voltage reaches 120V with standard bases or 250V with the 1794-TBN base.

3. What is the resolution of the 1794-IF4I module?
The 1794-IF4I provides 16-bit resolution for unipolar signals. Bipolar signals receive 15 bits plus a sign bit for accurate measurements.

4. Which terminal bases work with the 1794-IF4I?
Compatible bases include 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3T, 1794-TB3TS, and 1794-TBN. The 1794-TBN offers higher isolation voltage.

5. How do I know if the 1794-IF4I is working properly?
The 1794-IF4I has a bi-color OK status LED. A flashing green indicates power-up or configuration mode. A red light signals a hardware failure.