Allen-Bradley 1738-OB16EM12 Digital Output Module

The Allen-Bradley 1738-OB16EM12, also cataloged as the 1738-OB16EM12 Digital Output Module, serves as the primary 1738-OB16EM12 DC sourcing output module utilized to execute 24 V DC load switching across ArmorPoint distributed I/O platforms. Configured for point-level digital actuation in M12-connected field architectures, the Allen-Bradley 1738-OB16EM12 provides direct electrical switching of 16 sourcing outputs via a sealed 24 V DC backplane interface.

Suffix Breakdown & Model Matrix

The 1738-OB16EM12 designation follows ArmorPoint Bulletin 1738 structure:

• 1738: ArmorPoint I/O platform identifier

• OB16: 16-channel output block configuration

• EM12: M12 connectorized environmental module variant
  No further functional sub-encoding is defined for channel behavior or electrical rating.

Hardware Specifications

Backplane Bus Communication and Output Deterministic Switching

Within the ArmorPoint I/O architecture, output state execution is synchronized through PointBus communication cycles. The module updates 16-channel output states using change-of-state (COS) signaling over the distributed backplane, with current allocation managed per channel load. I/O density scaling is constrained by aggregate PointBus current budget (75 mA class system integration limit) and module grouping topology.

Frequently Asked Questions (FAQ)

Q: Can outputs be switched while the module is under load?
A: Yes. Each channel supports live switching, but inductive load suppression must be implemented externally to prevent back-EMF coupling into the output driver stage.

Q: What happens during RIUP (Removal and Insertion Under Power)?
A: During RIUP, all output states are forced to a safe de-energized condition until module reinitialization and backplane synchronization are completed.

Q: Is channel-to-channel electrical isolation implemented?
A: Outputs share a common sourcing architecture; isolation is not provided per channel and external isolation must be implemented at load side if required.

Field Installation Guidelines

M12 connectors must be fully engaged to maintain IP69K sealing integrity across vibration and washdown conditions. Output wiring shall be routed separately from high-frequency switching conductors to minimize induced noise coupling. All inductive loads require external suppression (diode or RC snubber) at field terminals. Maintain correct 24 V DC supply polarity and verify PointBus current availability prior to module insertion. Shield continuity must be maintained at cabinet entry to prevent ground loop injection into output return paths.