Allen Bradley 1738-IB4M12 Digital Input Modules

The Allen-Bradley 1738-IB4M12, also cataloged as the 1738-IB4M12 DC Input Module, operates as a dedicated hardware component for 24 VDC discrete signal ingestion and field device monitoring within Allen-Bradley ArmorPoint I/O platforms.

Hardware Specifications

Deterministic Ethernet/IP Networks and I/O Density Scaling

• EtherNet/IP Deterministic Networks: Transfers discrete input state transitions over the PointBus backplane to ArmorPoint network adapters, executing real-time cyclic polling without deterministic latency.
• I/O Density Scaling: Integrates four sinking input channels using standard M12 micro connections, maximizing local channel density in IP 67 washdown environments without secondary enclosures.
• Firmware Flash Compatibility: Supports synchronized execution profiles and hardware diagnostics through status LED indicators for module, network, and channel conditions.

Frequently Asked Questions

Q: What is the PointBus backplane current draw for the 1738-IB4M12 module? A: The module draws a maximum backplane current of 75 mA at 5 VDC from the PointBus power supply.

Q: What input filtering configuration is available on the 1738-IB4M12 input channels? A: The hardware enforces a fixed 0.5 ms hardware delay, supplemented by a user-configurable software filter delay ranging from 0 to 63 ms.

Q: Does the 1738-IB4M12 require a protective external enclosure for wet environments? A: No, the module features a sealed IP 67 housing designed for direct machine mounting in industrial environments.

Field Installation Guidelines

• Secure the sealed unit directly to machine structures using provided mounting hardware, ensuring flush seating against the mounting surface to maintain IP 67 integrity.
• Torque M12 micro cable connectors onto the module receptacles to hand-tight torque specifications to guarantee fluid sealing and prevent moisture intrusion.
• Maintain separate routing paths for sensor signal cables away from high-voltage AC conductors to reduce electromagnetic interference.
• Verify field supply power remains within the 10 to 28.8 VDC window prior to connecting input circuits.