The Allen-Bradley 1746-IM4 is a high-performance discrete AC input module designed for integration with the SLC 500 programmable logic controller (PLC) platform. This module features four (4) independent input channels rated for 200/240V AC operation. It is specifically engineered to interface high-voltage field devices, such as limit switches, pushbuttons, and motor starter contacts, directly into the SLC 500 system, making it an ideal solution for industrial environments utilizing 230V or 240V control standards.
Features
Four discrete AC input channels for high-voltage monitoring.
Electro-optical isolation rated at 1500V AC to protect the backplane and processor from field-side surges.
Hardware-based signal filtering with 35 ms (ON) and 45 ms (OFF) delays to mitigate electrical noise and mechanical contact bounce.
Low backplane power consumption (35 mA at 5V DC).
Robust design suitable for operation in temperatures ranging from 0 to 60 degC.
Applications
The 1746-IM4 is widely used in industrial automation systems where high-voltage AC signals must be monitored by a PLC. Common applications include machine control, conveyor systems, and process monitoring where 240V AC field devices are standard.
Technical Specifications
Parameter
Specification
Number of Inputs
4
Voltage Category
200/240V AC
Operating Voltage Range
170–265V AC (47–63 Hz)
Nominal Input Current
12 mA @ 240V AC
Max. Off-State Voltage
50V AC
Max. Off-State Current
2 mA
Max. Inrush Current
1.6 Amps (500 us duration)
Backplane Current (5V DC)
0.035 Amps
Total Heat Dissipation
1.6W
Operating Temperature
0 to 60 degC
Installation Guidelines
Power Down: Always remove power from the SLC 500 chassis before inserting or removing the module to prevent electrical damage.
Slot Placement: The module can be installed in any I/O slot of an SLC 500 chassis.
Wiring: Use appropriate wire gauges and ensure all terminal connections are secure. Route high-voltage AC wiring away from low-voltage DC or communication cables to minimize EMI.
Grounding: Ensure the chassis is properly grounded in accordance with local electrical codes and Allen-Bradley installation manuals.
Environment: Maintain adequate ventilation within the enclosure to ensure ambient temperature remains within the 0 to 60 degC range.
FAQ
What is the primary function of the 1746-IM4?
The 1746-IM4 serves as an interface module that converts 240V AC field signals into logic-level signals compatible with the SLC 500 PLC processor.
Does this module require 24V DC power from the backplane?
No, the 1746-IM4 draws 0 mA from the 24V DC backplane supply; it only requires 35 mA from the 5V DC supply.
