Introduction

The Allen Bradley 1746-FIO4I SLC 500 Fast Analog I/O Module is a combination analog input and output module developed for industrial control applications requiring relatively fast signal acquisition. It provides two differential analog input channels and two current output channels, combining monitoring and control functions within one SLC 500 module.

One important feature of the 1746-FIO4I is its independently selectable input configuration. Each input channel can accept either a 0–10 V DC voltage signal or a 0–20 mA current signal. This flexibility allows the module to connect with different types of process instruments without requiring separate voltage and current input modules.

The two analog current outputs provide 0–20 mA signals for compatible external control devices. With 12-bit input resolution, 14-bit output resolution, and a fast input response, the module supports applications where analog feedback and output control are important to the overall automation process.

The 1746-FIO4I occupies a single slot in a compatible SLC 500 I/O rack. During installation, engineers should consider backplane power requirements, signal wiring, grounding, shielding, and channel configuration. Correct installation and configuration help maintain stable analog signal performance in industrial environments.

For system integrators and maintenance teams operating Allen Bradley SLC 500 controllers, the 1746-FIO4I provides a practical solution for combining fast analog input monitoring with current output control.

Technical Specifications

Parameter	Specification
Brand	Allen Bradley
Model	1746-FIO4I
Product Type	SLC 500 Fast Analog I/O Module
Product Family	SLC 500
Module Configuration	Analog Combination Module
Number of Inputs	2 Differential
Number of Outputs	2 Current Outputs
Input Signal Type	Voltage / Current, Selectable per Channel
Voltage Input Range	0–10 V DC
Current Input Range	0–20 mA Nominal
Maximum Current Input	0–30 mA
Current Output Range	0–20 mA
Input Resolution	12 Bit
Output Resolution	14 Bit
Input Step Response	100 μs Nominal
Output Step Response	2.5 ms Nominal
Backplane Current at 5V DC	55 mA
Backplane Current at 24V DC	150 mA
Slot Occupancy	1 Slot
Dimensions	144.5 × 34.6 × 130.18 mm
Weight	0.36 kg / 0.79 lb

Recommended Related Models

The following Allen Bradley modules are related to the SLC 500 analog I/O product family. They offer different channel configurations or signal types for industrial analog control applications.

Model	Product Description
1746-FIO4I	SLC 500 Fast Analog Input / Current Output Module
1746-FIO4V	SLC 500 Fast Analog Input / Voltage Output Module
1746-NIO4I	SLC 500 Analog Input / Current Output Module
1746-NIO4V	SLC 500 Analog Input / Voltage Output Module
1746-NI4	SLC 500 High-Resolution Analog Input Module

Popular Related Models

Other Allen Bradley SLC 500 analog modules and accessories commonly used in industrial automation systems include:

1746-NI8 – SLC 500 8-Channel Analog Input Module.
1746-NI16I – SLC 500 16-Channel Analog Current Input Module.
1746-NI16V – SLC 500 16-Channel Analog Voltage Input Module.
1746-NO4I – SLC 500 4-Channel Analog Current Output Module.
1746-NO4V – SLC 500 4-Channel Analog Voltage Output Module.
1746-RT27 – SLC 500 Removable Terminal Block for compatible analog modules.

Note: The 1746-FIO4I and 1746-FIO4V have similar input configurations but different output signal types. Confirm the required output type, terminal block arrangement, and controller compatibility before selecting a replacement.

Applications

The Allen Bradley 1746-FIO4I SLC 500 Fast Analog I/O Module is designed for high-speed analog signal acquisition and current output control in industrial automation systems. It combines two differential analog input channels with two analog current output channels in a single-slot module.

Each input channel can be configured independently for voltage or current signals, allowing the module to interface with different types of industrial instruments and process devices.

Typical applications include:

Process monitoring: Acquire analog signals from pressure, temperature, flow, and other process transmitters.
Industrial control systems: Provide analog feedback signals to SLC 500 controllers for process monitoring and control.
Flow regulation: Generate current output signals for compatible control valves and flow-control equipment.
Pump and compressor systems: Monitor process variables and provide analog reference signals to external control devices.
Production machinery: Support fast analog signal acquisition in automated manufacturing equipment.
Instrumentation systems: Connect compatible voltage and current signal sources to PLC-based control systems.

Advantages

Combined Analog Input and Output

The 1746-FIO4I integrates two differential analog input channels and two current output channels. This combination reduces the need for separate input and output modules in applications requiring both signal acquisition and analog control.

Selectable Input Signal Types

Each input channel can be configured independently for voltage or current operation. The module supports 0–10 V DC and 0–20 mA nominal input ranges, providing flexibility when connecting industrial transmitters and sensors.

Fast Analog Response

Designed for applications requiring rapid signal processing, the module provides a nominal input step response of approximately 100 microseconds. This makes it suitable for faster analog monitoring tasks compared with many standard SLC 500 analog input modules.

14-Bit Analog Output Resolution

The two current output channels provide 14-bit resolution, supporting more detailed analog signal control for compatible external devices.

Flexible Current Output

Both output channels provide 0–20 mA current signals. They can be used to interface with compatible actuators, control valves, and other industrial equipment.

Compact Single-Slot Design

The module occupies one slot in an SLC 500 I/O chassis, helping conserve rack space while providing multiple analog signal functions.

Industrial PLC Integration

The 1746-FIO4I is designed for integration into compatible SLC 500 fixed and modular hardware systems, allowing analog signals to be incorporated into existing PLC control architectures.

Technical FAQs

Q1: What is the primary function of the 1746-FIO4I?

The 1746-FIO4I is a fast analog combination module that provides two differential analog input channels and two analog current output channels for SLC 500 programmable controllers.

Q2: How many analog input and output channels does it provide?

The module provides two analog inputs and two analog current outputs. Each input channel can be configured independently for voltage or current operation.

Q3: What input signal ranges does the module support?

The input channels support 0–10 V DC or 0–20 mA nominal signals. The current input circuit has a maximum input range of 0–30 mA, subject to the manufacturer's specifications.

Q4: What is the output signal range of the 1746-FIO4I?

Both analog output channels provide 0–20 mA current signals. The outputs are not individually isolated from one another.

Q5: What is the analog input resolution?

The module uses a 12-bit analog-to-digital converter for input signal conversion. Its analog output channels provide 14-bit resolution.

Q6: What is the input response time?

The nominal input step response is approximately 100 microseconds. This fast response makes the module suitable for applications that require relatively rapid analog signal acquisition.

Q7: How is the input channel configured for voltage or current signals?

The input mode is selected through the module's two-switch assembly. Each switch corresponds to one input channel. Follow the manufacturer's configuration instructions and disconnect power before accessing or changing the switches.

Q8: What backplane power does the module require?

The 1746-FIO4I requires 55 mA at 5V DC and 150 mA at 24V DC from the SLC 500 backplane. These values should be included when calculating the rack power supply capacity.

Q9: Can the 1746-FIO4I be installed in an existing SLC 500 system?

It is designed for compatible SLC 500 fixed and modular hardware systems and occupies a single I/O slot. Verify chassis compatibility, available backplane power, and terminal block requirements before installation.

Q10: What should be checked if an analog signal is inaccurate or unstable?

Inspect the input signal type selection, field wiring, signal grounding, cable shielding, and transmitter output. Also verify that the input signal remains within the permitted range and that analog common connections are correctly wired.

Look forward to your comments!Comment