Product Introduction
The Allen-Bradley 1746-IM8 is a digital AC input module designed for the SLC 500 family of programmable logic controllers. This 8-channel module accepts 170-265 Volts AC input signals, making it a versatile choice for monitoring discrete AC devices in industrial environments. As a genuine Rockwell Automation component, the 1746-IM8 ensures reliable performance and seamless integration into existing SLC 500 systems.
Technical Specifications
Below are the key technical parameters for the Allen-Bradley 1746-IM8 module, sourced directly from manufacturer data:
| Specification |
Value |
| Manufacturer |
Rockwell Automation |
| Brand |
Allen-Bradley |
| Part Number / Catalog No. |
1746-IM8 |
| Series |
SLC 500 |
| Module Type |
Digital AC Input Module |
| Voltage Range |
170-265 Volts AC |
| Inputs |
8 |
| Backplane Current (5 Volts DC) |
50 milliamps |
| Signal Delay |
35 or 45 milliseconds |
| Off State Current |
2 milliamps |
| Applications |
General Purpose 125 Volts DC Inputs |
| I/O Connection |
1746-HT and 1746-HCA |
| Step Response |
100 milliseconds in, 2.5 milliseconds out |
The module operates within a temperature range of -25 to 60 °C (-13 to 140 °F) and can withstand non-operating temperatures from -40 to 85 °C (-40 to 185 °F). It supports a relative humidity of 5% to 95% without condensation. Vibration resistance is approximately 1.0 g at 5 to 2000 Hz, and it handles a 30 g operating shock. Total heat dissipation is 3.1 Watts, with 0.35 Watts per point.
Real-World Applications
The Allen-Bradley 1746-IM8 excels in applications where reliable AC input sensing is critical. Common use cases include:
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Machine status monitoring: Detect the on/off state of AC-powered motors, solenoids, or contactors in manufacturing lines.
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Process control: Monitor limit switches and pressure switches in material handling or packaging machinery, ensuring accurate sequencing.
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Facility automation: Track HVAC equipment or lighting circuits in industrial buildings, providing input to the SLC 500 controller for energy management.
With its 8 isolated inputs and wide voltage range, the 1746-IM8 is a practical solution for retrofitting older AC control systems or expanding existing SLC 500 racks.
Installation & Setup
Installing the Allen-Bradley 1746-IM8 is straightforward. The module slots directly into any SLC 500 I/O chassis. Ensure the backplane connector is aligned properly and the module is firmly seated. For wiring, use the compatible I/O connection cables 1746-HT or 1746-HCA to connect field devices. The module accepts 170-265V AC inputs; verify that the input voltage matches your application before energizing. Always follow local electrical codes and disconnect power before handling the module.
Maintenance & Reliability
To maintain long-term reliability, periodically inspect the 1746-IM8 for dust accumulation and ensure the enclosure remains within the specified temperature and humidity ranges. Check that all wiring connections are tight and free from corrosion. The module’s solid-state design requires minimal maintenance, reducing downtime and lowering total cost of ownership. By keeping spares on hand, you can quickly replace a faulty module and minimize production interruptions.
Compatibility & Integration
The 1746-IM8 is designed exclusively for the Allen-Bradley SLC 500 platform. It integrates seamlessly with SLC 500 processors and other 1746-series I/O modules in the same chassis. The module communicates with the processor over the backplane, requiring only 50 mA at 5V DC. No external power supply is needed beyond the chassis backplane. This plug-and-play compatibility simplifies system design and reduces commissioning time.
Buying Guide
Before purchasing the Allen-Bradley 1746-IM8, verify that your SLC 500 chassis has an available slot and that the input voltage matches your field devices. Confirm the I/O connection type (1746-HT or 1746-HCA) is compatible with your wiring. For genuine, quality-assured automation parts, PLC Source PRO offers the 1746-IM8 with reliable sourcing and fast shipping. Ensure you order the correct part number to avoid compatibility issues.