Allen-Bradley 1746-NO4I SLC 500 Analog Output Module

Allen-Bradley 1746-NO4I SLC 500 Analog Output Module

Product Introduction

The Allen-Bradley 1746-NO4I is a vital component for any SLC 500 control system requiring precise analog control. This Analog Output Module is specifically engineered to convert digital signals from the controller into accurate 0 to +20 mA current signals. Its primary role is to drive actuators, valves, and other modulating devices, bridging the gap between the digital logic of the PLC and the analog demands of the field. Consequently, this module is indispensable for applications needing meticulous process control, such as in flow regulation or pressure management. Its compatibility with both fixed and modular SLC 500 hardware provides significant flexibility for system designers.

Technical Specifications

The 1746-NO4I boasts a robust set of technical features that ensure reliable operation in demanding industrial environments. It provides four (4) isolated current output channels, each capable of a standard output range of 0 to +20 mA. The module features a full-scale output of 21 mA and offers a 5% overrange capability extending to +21 mA - 1 LSB, allowing for calibration and control headroom. In terms of signal conversion, it utilizes a 14-bit resolution via an R-2R ladder network, ensuring fine control granularity.

Furthermore, the module's performance is characterized by rapid data handling. It achieves a fast channel update time of 512 microseconds for all channels simultaneously in parallel. Its step response is equally impressive, settling to 95% of the final value in just 2.5 milliseconds. The current output coding follows a 0 to +32764 integer format, providing a straightforward digital representation for the programmer. For signal integrity, it is advisable to use shielded cables like Belden 8761 for wiring.

Mechanical & Environmental Parameters

This SLC 500 module is designed to withstand typical industrial conditions. Its ambient operating temperature ranges from 0 to 60 degrees Celsius, while storage temperatures can extend from -40 to 85 degrees Celsius. It also tolerates a non-condensing ambient relative humidity of 5 to 95%. The module's open enclosure is specifically designed for installation within a 1746 chassis. Additionally, it uses a removable terminal block, which simplifies both initial wiring and subsequent maintenance or replacement.

Installation & Power Considerations

Installing the 1746-NO4I is a straightforward process. First, ensure the chassis is powered off, then slide the module into an available slot in the SLC 500 rack. An embedded selector switch on the module allows you to choose its power source. You can opt for the internal 5V backplane supply or an external 24V DC supply. The backplane current draw is 55 mA at 5V DC and 195 mA at 24V DC. If using an external source, it must be rated at 24 Volts DC +/- 10% with a maximum of 195 mA, especially crucial if the backplane lacks sufficient power. Also, ensure the output load range is between 0 and 500 ohms with a maximum load reactance of 100 µH.

Packaging & Logistics

This product listing is for the Allen-Bradley 1746-NO4I module only. The package will securely contain the module itself, complete with its removable terminal block for immediate installation. All necessary hardware for mounting is included as per standard factory packaging. For your convenience, we ship all orders via reliable global couriers such as Fedex, UPS, or DHL, ensuring fast and trackable delivery to your facility worldwide.

Packaging List

• 1 x 1746-NO4I Analog Output Module

• 1 x Removable Terminal Block

• 1 x Installation Instructions Guide

Frequently Asked Questions (FAQ)

1. What is the main function of the 1746-NO4I?
The 1746-NO4I's primary function is to convert digital commands from an SLC 500 PLC into precise 0-20 mA analog current signals. This output is then sent to control process instruments like variable speed drives, control valves, and chart recorders.

2. What is the resolution of this output module?
This Analog Output Module provides a high-resolution output of 14 bits. This granularity enables smooth and precise control over the connected actuator, allowing for very fine adjustments to the process variable.

3. How quickly does the module update its outputs?
The 1746-NO4I offers a fast update time of just 512 microseconds for all four output channels. This means it can refresh its outputs very quickly, making it suitable for dynamic control loops that require rapid response.

4. Do I need an external power supply for the 1746-NO4I?
It depends on your system's backplane power. The module can draw power internally from the 5V or 24V backplane. However, if the SLC power supply is insufficient, you must connect an external 24V DC +/- 10% source rated at 195 mA to ensure stable operation.

5. What is the maximum output load for this module?
The 1746-NO4I can drive a load range from 0 to 500 ohms with a maximum load reactance of 100 µH. Exceeding these values can cause inaccurate readings or damage the output circuit.