The Allen-Bradley 1771-OG (1771OG Digital Output Module) provides eight TTL digital output points with a specified 5 VDC interface for direct discrete signal switching within a PLC-5 I/O system.

Model Identification

The supplied catalog information identifies 1771-OG as an 8-point TTL output module for the PLC-5 platform. The supplied spare model is 1771OG. No additional revision or suffix information is provided.

Hardware Specifications

TTL Output Interface

The 1771-OG is identified as a TTL PLC-5 output module with eight digital output points. The supplied electrical information specifies 5 VDC and 165 mA.

TTL signaling uses defined digital voltage states rather than the higher-voltage field switching associated with conventional AC or DC output modules. External circuitry should therefore be electrically compatible with the module's specified TTL interface.

The supplied information does not specify TTL voltage thresholds, output impedance, propagation delay, short-circuit behavior, or individual channel current limits. These parameters should not be inferred from the 165 mA specification.

PLC-5 I/O Architecture

The 1771-OG operates as a discrete output component within the Allen-Bradley PLC-5 I/O architecture. Controller output data is transferred through the I/O backplane and presented at the module's output interface.

The eight-point configuration provides a lower-density digital output arrangement than 16-point PLC-5 modules. The supplied data does not identify Ethernet, EtherNet/IP, firmware, or network communication functions for this module.

Ordering Information

• 1 x Allen-Bradley 1771-OG digital output module
• 1 x 8-point TTL output module
• No external terminal assembly, mounting accessory, or supplementary kit is identified in the supplied data

Field Installation Guidelines

Module Handling

• Install the module only in a compatible PLC-5 I/O chassis.
• Inspect the backplane connector before insertion.
• Remove system power before installation or removal unless the applicable PLC-5 documentation explicitly permits energized replacement.
• Verify that the module is fully seated before system operation.
• Protect the module from electrostatic discharge during handling.

TTL Signal Wiring

• Verify that connected equipment is electrically compatible with the specified 5 VDC TTL interface.
• Do not connect field devices intended for higher-voltage PLC output circuits directly to TTL outputs.
• Keep TTL signal conductors separated from high-voltage switching conductors.
• Minimize unnecessary cable length where signal integrity may be affected.
• Maintain proper cabinet grounding and bonding.

Electrical Protection

• Do not infer individual channel current limits from the stated 165 mA specification.
• Verify the connected load requirements against the applicable Allen-Bradley technical documentation.
• Avoid unintended connections between TTL signal circuits and higher-voltage field supplies.
• Inspect all connections before applying power.

Frequently Asked Questions

• How many output points does the 1771-OG provide?

  The supplied product information identifies the 1771-OG as an 8-point digital output module for the PLC-5 platform.

• What output technology is used?

  The module is identified as a TTL PLC-5 output module. TTL-compatible external circuitry should be used according to the applicable electrical interface requirements.

• What voltage is specified for the output interface?

  The supplied specification lists 5 VDC. TTL voltage thresholds and logic-level limits are not provided in the supplied data.

• What is the stated current specification?

  The supplied product information lists 165 mA. It does not specify whether this value represents total module current or an individual channel limit.

• Can the output drive a conventional 24 VDC load directly?

  No such capability is established by the supplied data. The module is identified as a 5 VDC TTL output device, so 24 VDC loads should not be connected without appropriate interface hardware.

• Is the module discontinued?

  Yes. The supplied product information explicitly identifies the 1771-OG as discontinued by the manufacturer.

• Does the supplied data confirm hot-swapping?

  No. Hot-swap capability is not specified. Module installation or removal should therefore be performed with power removed unless the applicable PLC-5 documentation states otherwise.

• What is the specified operating temperature?

  No operating temperature is included in the supplied technical information. The applicable Allen-Bradley documentation should be consulted for environmental limits.