Product Overview

The Allen-Bradley 1794-IE8 belongs to the Flex I/O product family. This analog input module works with Flex I/O communication adapters and terminal bases. The Allen-Bradley 1794-IE8 interfaces with field transmitters, recorders, and process loop controllers. You get 8 user-configurable channels for flexible signal monitoring. The module uses successive approximation conversion for reliable data acquisition. The Allen-Bradley 1794-IE8 requires no calibration beyond factory settings.

Technical Specifications

The Allen-Bradley 1794-IE8 delivers precise analog input monitoring for Flex I/O systems. All parameters follow the official datasheet.

Input Specifications

• Number of inputs: 8 single-ended channels

• Input types: 0 to 20 mA, 4 to 20 mA, +/-10 VDC, 0 to 10 VDC

• Conversion type: Successive approximation

• Data format: 16-bit 2's complement, left justified

Resolution Details

• Unipolar resolution: 12 bits

• Bipolar resolution (voltage): 11 bits plus sign

• Voltage resolution unipolar: 2.56 mV per count

• Voltage resolution bipolar: 5.13 mV per count

• Current resolution: 5.13 µA per count

• The Allen-Bradley 1794-IE8 provides high precision for both signal types.

Accuracy & Drift

• Absolute accuracy at 25°C: 0.20% full scale

• Voltage accuracy drift: 0.00428% full scale per °C

• Current accuracy drift: 0.00407% full scale per °C

• Step response to 63% (voltage): 9.4 milliseconds

• Step response to 63% (current): 18.2 milliseconds

Conversion Rate

• Conversion rate: 256 microseconds on all channels

• The Allen-Bradley 1794-IE8 scans all 8 channels rapidly.

Overload Protection

• Maximum voltage overload: 30 Volts continuous

• Maximum current overload: 32 mA continuous

• Note: Overload applies to one channel at a time

Power Specifications

• External DC supply nominal: 24V DC

• External DC supply range: 10.0 to 31.2V DC (includes 5% AC ripple)

• External DC power supply current: 60 mA at 24 Volts DC

• FlexBus current: 60 mA at 5V DC

• Power dissipation at 31.2V DC: 3.0 Watts

• Thermal dissipation at 31.2V DC: 10.2 BTU per hour

Isolation

• Isolation voltage: 50 Volts continuous

• The Allen-Bradley 1794-IE8 provides basic isolation for safe operation.

Compatible Terminal Bases

The Allen-Bradley 1794-IE8 installs on these base units:

• 1794-TB2

• 1794-TB3

• 1794-TB3S

• 1794-TB3T

• 1794-TB3TS

Status Indicators

• Indicator: 1 green/red power and status LED

• The Allen-Bradley 1794-IE8 provides clear module status indication.

Environmental Specifications

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

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

• Vibration: 5g at 10 to 500 Hz

• Operating shock: 30g

• Non-operating shock: 50g

Physical Specifications

• Wire size: Determined by installed terminal base

• Mounting: DIN rail or direct panel mount

• Enclosure style: Open-style enclosure

• UPC: 10612598137814

Compatibility

The Allen-Bradley 1794-IE8 works with Flex I/O communication adapters including:

• Ethernet adapters

• ControlNet adapters

• Remote I/O adapters

Installation Guide

Follow these steps to install the Allen-Bradley 1794-IE8 correctly.

1. Mount the terminal base on DIN rail or directly on the panel.

2. Select a compatible base from 1794-TB2, TB3, TB3S, TB3T, or TB3TS.

3. Wire analog field devices to the terminal base following signal ranges.

4. Insert the 1794-IE8 into the terminal base assembly.

5. Connect external 24V DC power at 10.0 to 31.2V range.

6. Configure input channels for 0-20mA, 4-20mA, +/-10V, or 0-10V signals.

7. Monitor the power/status LED on the Allen-Bradley 1794-IE8 for proper operation.

Packing List

This package for the Allen-Bradley 1794-IE8 includes the following items.

• Allen-Bradley 1794-IE8 analog input module (one unit)

• Product documentation and installation guide

• Anti-static protective bag

Frequently Asked Questions (FAQ)

1. How many input channels does the 1794-IE8 have?
The Allen-Bradley 1794-IE8 has 8 single-ended input channels. All channels are user-configurable for current or voltage signals.

2. What signal ranges does the 1794-IE8 accept?
The Allen-Bradley 1794-IE8 accepts 0-20mA, 4-20mA, +/-10VDC, and 0-10VDC. This covers most analog instrument output ranges.

3. What is the resolution of the 1794-IE8?
The resolution is 12 bits for unipolar signals. For bipolar voltage, the Allen-Bradley 1794-IE8 provides 11 bits plus sign with 5.13 mV per count.

4. Does the 1794-IE8 require calibration?
No, the Allen-Bradley 1794-IE8 does not require calibration. Factory settings provide 0.20% full scale accuracy at 25°C.

5. What terminal bases work with the 1794-IE8?
The Allen-Bradley 1794-IE8 works with 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3T, and 1794-TB3TS. One terminal base is needed per module.