Allen-Bradley 1756-OB32 ControlLogix 10-31VDC Output Module, 32 Points

Are you struggling to fit enough discrete outputs into a crowded ControlLogix chassis without sacrificing performance or reliability?

Product Overview

The Allen-Bradley 1756-OB32 is a high-density 24VDC discrete output module from the ControlLogix series. This component provides 32 points of sourcing output in a single slot, dramatically increasing point density while conserving chassis space. It is designed to drive a wide range of output devices such as pilot lamps, relays, contactors, panel annunciators, solenoids, buzzers, sirens, horns, and other actuating equipment. The module mounts directly into a local or remote ControlLogix chassis and uses a Removable Terminal Block (RTB) for field wiring.

Technical Specifications Breakdown

Key parameters for the 1756-OB32 are listed below for quick reference:

Industry Applications

In automotive assembly lines, this module controls numerous solenoids and contactors for fixture clamping and part transfer. Its high channel count reduces the number of modules needed, lowering overall system cost and simplifying wiring. In material handling systems, the 1756-OB32 drives indicator lights and alarms, providing clear operator feedback. The fast output delay times (60 µs off-to-on nominal) ensure responsive actuation for time-critical processes.

Installation & Setup Guidance

Before installation, ensure the chassis and power supply are properly grounded. The module occupies a single slot in any ControlLogix local or remote chassis. A Removable Terminal Block (RTB) is required; use either the cage clamp 1756-TBCH or the spring clamp 1756-TBS6H. Connect field wiring to the RTB before inserting it into the module. For fuse protection, the recommended fuse is a 5x20mm 800 mA unit (Littelfuse p/n SP001.1003 or Schurter p/n 216.800). Configure communication formats (scheduled output data, rack optimization, listen-only modes) and fault/program mode states (Hold Last State, On, Off) per point using the ControlLogix programming software.

Maintenance & Reliability

Periodically inspect the module’s 32 LED indicators to verify channel status and controller commands. Ensure ambient temperature remains within 0 to 60 °C operating range. Keep the enclosure free of dust and contaminants. The module’s linear derating from 0.5 A per point at 50 °C to 0.35 A at 60 °C must be considered when sizing loads. No internal maintenance is required; replace the module if faults persist after verifying wiring and configuration.

Compatibility & Integration

This module is compatible with any ControlLogix processor, including recent versions. It supports scheduled output data, output data, rack optimization, listen-only rack optimization, and listen-only output data communication formats. The module only supports sourcing configuration. Use the 1756-TBCH or 1756-TBS6H RTB for field wiring connections. The module maintains specific identification information to distinguish it from other modules in the system.

Selection Guide & Purchasing Advice

When selecting the 1756-OB32, consider your voltage requirements (10-31.2VDC) and current needs per point (0.5A max at 50°C). For higher ambient temperatures, derate accordingly. Ensure your chassis has an available slot and that you order the appropriate RTB. AutoDCSTech offers this module with fast shipping and expert support. Please verify current lifecycle status and availability with AutoDCSTech before ordering.

Troubleshooting & Common Issues

If an output does not energize, check the LED indicator for that channel. If the LED is off, verify the controller’s program logic and fault/program mode configuration. If the LED is on but the load does not actuate, inspect the wiring and the RTB connection. Confirm the load voltage is within the 10-31.2VDC range and that the load current does not exceed the derated limits. For intermittent faults, check for loose RTB connections or marginal power supply voltage.