1746-IV8 8-Channel 24V DC Discrete Input Module

1746-IV8 8-Channel 24V DC Input Module

Product Introduction

The Allen-Bradley 1746-IV8 is a compact Discrete Input module for the SLC 500 programmable controller platform. It accepts 24 Volt DC digital signals from field devices such as limit switches, auxiliary contacts, and proximity sensors. This module features 8 input points in a single group, which simplifies wiring and reduces installation time. Therefore, it offers an economical and efficient solution for smaller automation applications requiring reliable digital signal acquisition.

Technical Specifications

The 1746-IV8 module operates with a nominal input voltage of 24 Volts DC. Its acceptable voltage range spans from 10 to 30 Volts DC, providing flexibility for various field devices. The nominal input current per point is 8 mA at 24V DC, ensuring reliable signal detection.

For signal timing, the module delivers consistent and predictable performance. Both the maximum ON-state signal delay and the maximum OFF-state signal delay are 8 milliseconds. The maximum OFF-state voltage is 5.0 Volts DC, while the maximum OFF-state current is 1 mA. The 1746-IV8 draws a backplane current of only 0.050 Amperes at 5 Volts DC, which places a very minimal load on the chassis power supply.

Mechanical & Environmental Parameters

The Allen-Bradley 1746-IV8 performs reliably in demanding industrial environments. It features an operating temperature range from 0 to +60 °C (+32 to +140 °F) and a storage temperature range between -40 °C and +85 °C (-40 °F to +185 °F). Furthermore, the module operates effectively in environments with 5 to 95% relative humidity, provided there is no condensation.

This single-slot module has a compact footprint and fits into any available slot within the SLC 500 chassis. Its open-type enclosure suits it for use in industrial control panels and equipment rooms. Additionally, the front panel includes LED indicators for each input channel, which allows for quick visual status checks during operation.

Installation Guide

Installing the 1746-IV8 is a simple and fast procedure. This single-slot module plugs directly into any vacant slot within the SLC 500 chassis. First, power off the chassis completely. Next, carefully align the module's circuit board with the card guides inside the chassis, and then slide it firmly into place until it seats fully against the backplane connector. Please note that removing or inserting this module with power applied can cause an electrical arc, which may lead to personal injury or damage to the module contacts.

After physical installation, you can connect your 24V DC field devices. The 8 inputs share a common return terminal. The module requires 14 AWG (2 millimeter) cables for signal termination. It does not require an external power supply because it draws all necessary power from the backplane. Moreover, you can install this module in a local I/O rack, an extended rack, or a distributed I/O rack, offering flexibility for various system configurations.

Packaging List

Your shipment of the Allen-Bradley 1746-IV8 will include the following item:

• (1) Allen-Bradley 1746-IV8 SLC 500 Discrete Input Module

The module ships in protective anti-static packaging to ensure it arrives in perfect condition. Standard wiring tools and a suitable 24V DC power supply 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 types of field devices can I connect to the 1746-IV8 module?
You can connect various 24V DC sourcing devices, including limit switches, proximity sensors, auxiliary contacts, push buttons, and selector switches. The module accepts signals from any device that provides a DC sourcing output within the 10-30V range.

2. Can I install the 1746-IV8 in any slot of the SLC 500 chassis?
Yes, you can. The Allen-Bradley 1746-IV8 is a single-slot module that fits into any vacant slot. It works in local racks, extended racks, and distributed I/O racks, provided the host processor supports the I/O configuration.

3. What is the difference between the 1746-IV8 and the 1746-IV32?
The primary difference is the channel count. The 1746-IV8 has 8 input channels in a single group, while the 1746-IV32 offers 32 input channels arranged in four groups of eight. Choose the 1746-IV8 for smaller applications requiring fewer inputs.

4. Why must I power off the chassis before removing or installing this module?
Powering off prevents electrical arcing. When you remove or insert the 1746-IV8 with power applied, an arc can occur. This arc may cause personal injury and can also wear the contacts on both the module and its mating connector, which leads to reduced reliability over time.

5. How do I verify that the module is working correctly after installation?
You can check the status LEDs on the front panel. Each of the 8 inputs has a dedicated indicator. When a valid voltage reaches an input, its corresponding LED will illuminate, which confirms that the signal is arriving and the module is functioning properly.