1794-IF4I Isolated Analog Input Module Allen-Bradley

1794-IF4I Flex I/O Isolated Analog Input Module

Product Introduction

The Allen-Bradley 1794-IF4I module offers a robust solution for analog signal integration within the Flex I/O platform. This module delivers precise measurement of voltage and current signals. It features four isolated differential-ended inputs. This isolation provides superior protection against transient voltages and common-mode noise. Users can configure each channel independently to match specific sensor outputs. The module works seamlessly with various terminal base units. Its sigma-delta conversion ensures high accuracy across a wide temperature range. Consequently, the 1794-IF4I is an ideal choice for demanding industrial applications.

Key Technical Specifications

This module supports a broad spectrum of input signal types. For current, you can configure it for 0-20 mA, 4-20 mA, or ±20 mA ranges. For voltage, it handles ±10V, 0-10V, ±5V, and 0-5V ranges. The 1794-IF4I offers a resolution of 16 bits for unipolar signals and 15 bits plus sign for bi-polar signals (signed representation) . This resolution translates to precise counts of 0.156 mV/cnt for unipolar voltage and 0.313 mV/cnt for bi-polar voltage. Furthermore, it provides high accuracy of 0.1% full scale at 25 °C for both current and voltage inputs.

The module incorporates an internal sigma-delta analog-to-digital converter (ADC). It supports update rates of 2.5 ms, 5.0 ms, and 7.5 ms. Users can select the rate based on their application's speed requirements. The 1794-IF4I also offers excellent step response times. At a 1200 Hz conversion rate, the response is 0.6 ms. At 150 Hz, it is 26.7 ms. Additionally, the accuracy drift is minimal. It is only 0.0028% full scale/°C for voltage and 0.0038% full scale/°C for current. This stability ensures reliable measurements in fluctuating environmental conditions.

Power and Isolation Details

Power for the 1794-IF4I comes from an external 24V DC supply. The nominal voltage range is 19.2 to 31.2V DC, inclusive of a 5% AC ripple. The module draws 80 mA at 24V DC. It also consumes 50 mA from the FlexBus at 5V DC. The isolation voltage is a critical parameter. Its continuous isolation rating depends on the terminal base used. With the 1794-TB2, 1794-TB3, or 1794-TB3S base, it provides 120V continuous isolation. However, when installed on the 1794-TBN base, the isolation voltage increases to 250V continuous. This flexibility allows you to match the module's protection level to your system's needs. Meanwhile, the maximum power dissipation is 2.0 W at 31.2V DC.

Mechanical and Environmental Parameters

The Allen-Bradley 1794-IF4I is built for industrial environments. Its operating temperature range is 0 to 55 °C (32 to 131 °F). For storage, it can withstand temperatures from -40 to 85 °C (-40 to 185 °F). The module handles vibration of 5g at 10 to 500 Hz. It also withstands an operating shock of 30g and a non-operating shock of 50g. The non-condensing relative humidity tolerance is 5 to 95%. This module uses an open-type enclosure. Its thermal dissipation is rated at a maximum of 6.8 BTU/hr. These specifications ensure it performs reliably in harsh factory floor conditions.

Installation and Compatibility

Mounting the 1794-IF4I is straightforward. It is designed for DIN rail installation. However, it can also be panel-mounted. The module is compatible with several terminal base units. These include the 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3T, 1794-TB3TS, and 1794-TBN. The actual wire size used is determined by the chosen terminal base. A bi-colored LED status indicator provides diagnostic information. It flashes green during power-up reset or when the module is in configuration mode. It turns red if the initial hardware test fails. Therefore, operators can quickly assess the module's operational status.

Packaging List

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

• Installation Instructions Manual

Shipping Information

We ship all orders using reputable global carriers. Your 1794-IF4I will be dispatched via FedEx, UPS, or DHL. This ensures fast and reliable delivery to your facility.

Frequently Asked Questions (FAQ)

Q1: Can I use the 1794-IF4I with a 2-wire 4-20 mA sensor?
Yes, the 1794-IF4I supports 4-20 mA signals. However, the sensor's loop power must be provided externally, as this module does not supply loop power.

Q2: What is the difference between the 1794-IF4I and the standard 1794-IF4?
The primary difference is the isolation. The 1794-IF4I has individually isolated channels, while the standard IF4 typically has non-isolated or group-isolated inputs. This makes the IF4I better suited for applications with high common-mode voltage differences.

Q3: How do I configure the input range for each channel?
You configure the input range using the control system's software, such as RSLogix 5000 or Studio 5000. The 1794-IF4I supports user-configurable ranges for each of its four channels.

Q4: What terminal base unit should I buy for 250V isolation?
To achieve 250V continuous isolation, you must use the 1794-TBN terminal base unit with the 1794-IF4I. Other base units provide 120V isolation.

Q5: Does the module come pre-calibrated?
Yes, the Allen-Bradley 1794-IF4I arrives factory-calibrated. You can also perform recalibration in the field if required by your application or maintenance schedule.