Product Overview

The Allen-Bradley 1746-NO4I is an analog output module. It belongs to the SLC 500 product platform. This module features four (4) current output channels with a range of 0 to +20 mA.

The module is compatible with both fixed and modular style SLC 500 hardware. Furthermore, it includes an embedded selector switch for power supply source selection. Therefore, it suits a wide range of analog control applications.

General Specifications

The 1746-NO4I offers high-quality analog output capability for SLC 500 systems.

• Manufacturer: Rockwell Automation.

• Brand: Allen-Bradley.

• Series: SLC 500.

• Part Number/Catalog No.: 1746-NO4I.

• Module Type: Analog Output Module.

• Number of Outputs: Four (4).

• UPC: 10662073735912.

• Open Enclosure: Yes (compatible only with 1746 chassis).

Output Specifications

The 1746-NO4I provides precise current outputs for field devices.

• Output Current Range: 0 to +20 mA.

• Full Scale Output: 21 mA.

• Overrange Capability: 5% (0 to +21 mA - 1 LSB).

• Load Range: 0 to 500 ohms.

• Maximum Load Reactance: 100 µH.

• Resolution: 14 bits (via R-2R ladder conversion method).

• Current Output Coding: 0 to +32764.

• Update Time: 512 microseconds (all channels in parallel).

• Step Response: 2.5 milliseconds (to 95%).

Backplane Power Consumption

The 1746-NO4I draws power from both backplane voltages.

• Backplane Current (5 Volts): 55 milliamps.

• Backplane Current (24 Volts DC): 195 milliamps.

• Backplane Isolation: 500 Volts DC.

Power Supply Options

The 1746-NO4I includes an embedded selector switch for power source selection.

• Internal Power Supply: Module utilizes supply from the backplane.

• External Power Supply: 24V ±10% at 195 mA maximum.

Important Note: Some applications require 21.6 to 26.4 Volts DC power when there is not enough power flowing from the SLC power supply. Therefore, verify adequate power before operation.

Accuracy and Drift

The 1746-NO4I maintains accuracy across temperature variations.

• Maximum Overall Accuracy Drift: ±70 ppm/°C of full-scale accuracy.

Thus, the module provides stable output even with ambient temperature changes.

Typical Applications

The 1746-NO4I suits various analog output control applications.

• Driving modulating instruments such as I/P converters and valve positioners.

• Representing Control Output (CO) of a PID controller.

• Manual loading station operator commands.

• Signal re-transmission for indication, data logging, or signal conversion.

• Integration with SLC 500 fixed or modular hardware.

Signal Assignment

The appropriate output signal is assigned by modifying the module properties. For PID control loops, the analog output typically represents the Control Output. For manual loading stations, it represents the manual command entered by the operator. Hence, the module adapts to different control strategies.

LED Indicator

The 1746-NO4I includes an LED status indicator on the front panel. Consequently, operators can quickly verify module power and operational status.

Wiring Recommendations

The 1746-NO4I simplifies field wiring with several features.

• Recommended Cable: Shielded communication cable such as Belden 8761 or equivalent.

• Cable Length: Keep as short as possible to minimize noise pickup.

• Terminal Block: Removable terminal for simplified wiring and ease when replacing the module.

For wiring convenience, the module is provided with a removable terminal block. Therefore, module replacement does not require rewiring.

Environmental Specifications

The 1746-NO4I withstands typical industrial conditions.

• Ambient Operating Temperature: 0 to 60°C.

• Storage Temperature: -40 to 85°C.

• Relative Humidity: 5 to 95% (non-condensing).

Key Features

The 1746-NO4I offers several advantages for analog output applications.

Four Isolated Current Outputs:
Provides 4 channels of 0-20mA output. Therefore, it controls multiple analog devices from a single module.

High Resolution:
14-bit resolution via R-2R ladder conversion method. Consequently, it delivers fine control for precision applications.

Fast Update Time:
All channels update in parallel every 512 microseconds. Hence, it responds quickly to control algorithm changes.

Selectable Power Supply:
Embedded switch allows internal (backplane) or external 24V power source. Thus, it adapts to different system power configurations.

Wide Load Range:
Drives loads from 0 to 500 ohms. For this reason, it works with most analog input cards and I/P converters.

Removable Terminal Block:
Simplifies wiring and module replacement. Consequently, maintenance downtime is reduced.

Factory Calibrated:
No field calibration required. Therefore, it is ready to use out of the box.

Low Accuracy Drift:
±70 ppm/°C of full scale ensures stable operation across temperature changes. Hence, it suits unconditioned environments.

Compatibility

The 1746-NO4I is compatible with:

• SLC 500 fixed hardware controllers.

• SLC 500 modular hardware controllers.

• 1746 chassis only (open enclosure).

Installation Guidelines

Install the 1746-NO4I in any available slot of a 1746 chassis. First, ensure the chassis power supply can provide the required 55 mA at 5V and 195 mA at 24V. Then, insert the module into the slot.

Select the power supply source using the embedded selector switch. Use internal supply for backplane power or external supply for 24V ±10% external power. For external power, provide 21.6 to 26.4 VDC at 195 mA maximum.

Wire analog outputs using shielded cable such as Belden 8761. Keep cable lengths as short as possible. Connect the load (0-500 ohms) to the output terminals. The module provides 0-20mA output with 5% overrange capability (0-21mA). The update time is 512 µs for all channels.

What is in the Box

Please inspect all items upon delivery.

• Allen-Bradley 1746-NO4I analog output module.

• Removable terminal block.

• Installation instruction manual.

Frequently Asked Questions (FAQ)

1. How many analog output channels does the 1746-NO4I have?

The 1746-NO4I provides four (4) analog current output channels. The output range is 0 to +20 mA.

2. What is the resolution of this analog output module?

The 1746-NO4I has 14-bit resolution. It uses an R-2R ladder conversion method for precise output generation.

3. What is the update time for all channels?

All four channels on the 1746-NO4I update in parallel. The update time is 512 microseconds.

4. What load range can this module drive?

The 1746-NO4I can drive loads from 0 to 500 ohms. The maximum load reactance is 100 µH.

5. Can this module use external power instead of backplane power?

Yes. The 1746-NO4I includes an embedded selector switch. Therefore, it can be configured to use either internal (backplane) power or external 24V ±10% power.