Allen-Bradley 1746-NI16I SLC 500 Analog Input Module

1746-NI16I 16-Channel Analog Input Module

Product Introduction

The Allen-Bradley 1746-NI16I is a high-density Analog Input Module designed for the SLC 500 programmable controller system. It accepts analog current signals from field devices such as transmitters, transducers, and sensors. This module features 16 input channels, each configurable for 0 to 20 mA, 4 to 20 mA, ±20 mA, or 0 to 1 mA. Therefore, it delivers precise measurement capabilities for process variables like pressure, temperature, flow, and level in industrial control applications.

Technical Specifications

The 1746-NI16I module offers exceptional flexibility with its 16 analog input channels. Each channel supports four current ranges: 0 to 20 mA, 4 to 20 mA, ±20 mA, and 0 to 1 mA. The module provides 16-bit resolution, ensuring accurate and reliable signal conversion. Its conversion type is Sigma-Delta, which delivers high precision and noise rejection.

The module draws a backplane current of 125 mA at 5 Volts DC and 75 mA at 24 Volts DC. Total backplane power consumption is 2.425 Watts maximum (0.625 Watts at 5V DC and 1.8 Watts at 24V DC). The thermal dissipation is 2.43 Watts. The input impedance is 249Ω, while the maximum current input is ±30 mA. Furthermore, the module provides 500V AC isolation for 1 second, which enhances system safety and noise immunity.

For signal filtering, the 1746-NI16I includes a low-pass digital filter with programmable frequencies. You can select from 6 Hz, 10 Hz, 20 Hz, 40 Hz, 60 Hz, 80 Hz, 100 Hz, or 250 Hz. The bandwidth ranges from 6 to 250 Hertz, and the step response varies from 9 to 630 milliseconds depending on the selected filter frequency. The module's time to actuate is less than 5 seconds.

Data Format and Configuration

The Allen-Bradley 1746-NI16I offers multiple user-selectable data formats to suit different control strategies. You can configure the module for Engineering Units, Scaled for PID, Proportional Counts with a -32,768 to +32,767 range, or Proportional Counts with a User-Defined Range (Class 3 only). This flexibility allows you to integrate the module seamlessly with various programming environments.

Additionally, the module features open-circuit detection per input channel, which helps identify wiring faults or sensor failures quickly. The common mode voltage range is ±10.25 Volts relative to the analog common terminal. The maximum voltage input between analog common and any input terminal is ±8 Volts.

Mechanical & Environmental Parameters

The 1746-NI16I performs reliably in a wide range of industrial environments. Its operating temperature range extends from -25 to +60 °C (-13 to +140 °F), while the storage temperature range is between -40 and +85 °C (-40 to +185 °F). The module operates effectively in conditions with 5 to 95% relative humidity without condensation.

This single-slot module fits into any SLC 500 chassis slot except Slot 0, which is reserved for the processor. The front panel includes 5 green status indicators: one for the module status and one for each group of 4 channels. These LEDs provide visual confirmation of module health and channel operation.

Installation and Wiring Guide

Installing the 1746-NI16I is a straightforward process. First, power off the SLC 500 chassis completely. Next, insert the module into any available slot except Slot 0. Slide it firmly into place until it seats fully against the backplane connector.

For wiring, the module uses a 25-pin D-shell connector (AIFM connector). We recommend using Belden #8761 cable or an equivalent shielded cable for optimal signal integrity. The maximum wire size is 14 AWG, and you can terminate up to two wires per terminal. When wiring signals, note that it is not necessary to remove the terminal blocks from the module. However, if you do remove a terminal block, use the label next to it to identify the correct location and module type.

Applications

Analog inputs like the Allen-Bradley 1746-NI16I interface with process variables to measure their magnitude. This module is primarily useful for monitoring applications or as a feedback signal for closed-loop control systems. By implementing control methods like the Proportional-Integral-Derivative (PID) algorithm, you can achieve manual or automatic control. Without this feedback signal, automatic control cannot function fully.

Packaging List

Your shipment of the Allen-Bradley 1746-NI16I will include the following item:

• (1) Allen-Bradley 1746-NI16I SLC 500 Analog Input Module

The module ships in protective anti-static packaging to ensure it arrives in perfect condition. A 25-pin D-shell connector and wiring tools are necessary for installation, but these items are not included with the module.

All orders ship promptly via FedEx, UPS, or DHL to guarantee fast and dependable delivery.

Frequently Asked Questions (FAQ)

1. What input signal types does the 1746-NI16I support?
The Allen-Bradley 1746-NI16I supports four current ranges: 0 to 20 mA, 4 to 20 mA, ±20 mA, and 0 to 1 mA. You can configure each channel individually for the appropriate signal type.

2. Can I install this module in Slot 0 of the SLC 500 chassis?
No, you cannot. The 1746-NI16I fits into any I/O module slot except Slot 0. The processor or power supply typically occupies Slot 0, depending on your chassis configuration.

3. What is the purpose of the programmable input filter?
The programmable filter reduces noise from the analog signal. You can select a filter frequency from 6 Hz to 250 Hz. A lower frequency provides more noise rejection but results in a slower step response. Choose the setting based on your specific application requirements.

4. How do I know if a channel has an open circuit?
The 1746-NI16I includes open-circuit detection per channel. When the module detects an open circuit, you can identify this condition through the configured data format or status bits in your control program. The module's time to actuate for this detection is less than 5 seconds.

5. What type of cable should I use for wiring the 1746-NI16I?
We recommend using Belden #8761 shielded cable or an equivalent shielded instrument cable. Shielded cable helps minimize electrical noise and ensures accurate signal transmission. The maximum wire size is 14 AWG, and you can terminate up to two wires per terminal.