Allen-Bradley 1746-IM4 SLC 500 AC Input Module

Allen-Bradley 1746-IM4 SLC 500 AC Input Module

Product Introduction

The 1746-IM4 belongs to the Allen‑Bradley SLC 500 family. This digital AC input module provides four input channels in a single group. Each channel supports an AC voltage range from 170V to 265V at 47‑63 Hz.

You can install this compact module into any SLC 500 chassis. It works perfectly for applications that need only a few AC inputs. The backplane draws only 35 milliamps at 5 Volts DC, which is very low.

For signal response, the 1746-IM4 has an ON delay of 35 milliseconds and an OFF delay of 45 milliseconds. The maximum off‑state voltage reaches 50V AC, while off‑state current stays below 2 mA. Nominal input current sits at 12 mA at 240V AC.

Technical Specifications

The 1746-IM4 module handles general‑purpose AC signaling devices. Each of the four input channels operates independently. The module provides voltage isolation between the backplane and I/O circuits, tested at 1500V AC.

Additionally, it meets NEMA standard ICS 2‑230 for noise immunity. Use the 1746-HT or 1746-HCA removable terminal block (RTB) for wiring.

Key electrical parameters are listed below:

• Input voltage range: 170–265V AC, 47–63 Hz (nominal 200/240V AC)

• Off‑state voltage max: 50V AC

• Off‑state current max: 2 mA

• Nominal input current: 12 mA at 240V AC

• Inrush current max: 1.6 Amperes

• Inrush duration max: 500 microseconds (0.5 ms)

• Backplane current (5V DC): 35 mA

• Power dissipation per point: 0.35W

• Total heat dissipation: 1.6W

Mechanical & Environmental Ratings

The 1746-IM4 survives harsh conditions with ease. Its operating temperature range is 0 to +60 °C (+32 to +140 °F). Storage temperature spans from -40 °C to +85 °C (-40 °F to +185 °F).

Relative humidity can range from 5% to 95% without condensation. The module withstands operational shock of 30G. It also handles vibration of 2.5G at 57‑500 Hz.

Furthermore, it holds important certifications. The 1746-IM4 is UL‑A196, CSA, and C‑UL certified for hazardous environments. It is also rated for Class I, Division 2, Groups A, B, C, D locations.

Installation Guidelines

Installing the 1746-IM4 is quick and simple. First, turn off chassis power completely. Then insert the module into any available slot of an SLC 500 chassis. Push firmly until fully seated.

Next, connect field wiring using an RTB like the 1746-HT or 1746-HCA. Each of the four input channels accepts two wires. Pay attention to AC supply polarity because the module is designed for AC signals only.

For DC input devices, you must use an external interposing relay. Supply AC voltage to the relay coil. The relay contacts then safely switch the DC signal.

Finally, power on the chassis. The processor automatically detects the 1746-IM4 during its I/O scan. There is no hard limit on how many modules you can install. The only restrictions come from your processor’s I/O capacity and memory size.

Packaging List

• One Allen‑Bradley 1746-IM4 AC input module

• One removable terminal block (RTB)

• Label sheet for channel identification

• Quick start guide

Note: No certificates or warranty documents are included. Contact your supplier for warranty terms.

Shipping & Delivery

We ship all orders via FedEx, UPS, or DHL. Delivery takes 3‑7 business days depending on your region.

Frequently Asked Questions (FAQ)

1. Can the 1746-IM4 work with 120V AC signals?
No. The 1746-IM4 requires 170‑265V AC. For 120V AC applications, choose the 1746-IA4 or 1746-IA8 module instead.

2. What is the main difference between 1746-IM4 and 1746-IM16?
The 1746-IM4 has only 4 input channels and draws 35 mA backplane current. The 1746-IM16 has 16 channels and draws 85 mA. Choose based on your channel count needs.

3. Can I use the 1746-IM4 with DC voltage?
The module expects AC signals. If you apply DC voltage, detection may fail or become erratic. Use an interposing AC relay to interface DC field devices safely.

4. Why does my 1746-IM4 respond slowly?
The ON delay is 35 ms and OFF delay is 45 ms by design. This built‑in filtering prevents false triggers from electrical noise. This response time is normal for AC input modules.

5. Does the 1746-IM4 require external fuses?
Allen‑Bradley does not include onboard fuses. We strongly recommend adding external fast‑acting fuses (rated 250V, 0.2A) to each input circuit for proper protection.