Overview
The Allen-Bradley 1756-OB16D is a ControlLogix-series diagnostic DC output module designed for industrial control and automation systems requiring reliable, fault-tolerant digital switching. This 16-point output module operates in the 19.2–30VDC range with a nominal 24VDC supply and delivers up to 2A per point for pilot-duty loads. Built-in diagnostic capabilities at the point level—including no-load detection, output verification, and short-trip diagnostics—enable quick identification of wiring faults and load failures without interrupting production.
Key Features
- 16 individually fused digital outputs with pilot-duty 2A rating per point
- Point-level diagnostics: no-load detection, output verification, short-trip analysis
- Operates 19.2–30VDC, standard 24VDC nominal supply
- 0.6 ms response time for critical switching applications
- Chassis-mount with 36-pin terminal block interface (1756-TBCH or 1756-TBS6H required)
- Configurable fault-mode and program-mode behavior per point
- Complies with CE, UL, CSA, IECEx, and RCM certifications
Technical Specifications
- Module Type: Digital Diagnostic Output
- Output Points: 16 (grouped 8 per fused circuit)
- Output Voltage Range: 19.2–30VDC
- Nominal Supply: 24VDC
- Output Current Rating: 2A maximum at 30°C per point; 1A maximum at 60°C
- On-State Voltage Drop: 1.2VDC maximum at 2A
- Minimum Load Current: 3 mA per point
- Off-State Leakage: 1 mA maximum per point
- Backplane Current (Module): 140 mA at 24VDC; 250 mA at 5.1VDC
- Backplane Power: 4.64 W
- Response Time: 0.6 millisecond
- Operating Temperature: 0–60°C
- Mounting: ControlLogix 1756 chassis (any available slot)
- Connection: 36-pin tension-clamp terminal block
- Weight: 0.53 lbs
- Certifications: CE, UL, CSA, KC, MARINE, NRTL, RCM, IECEx, Australian RCM
- Series/Status: ControlLogix (Active lifecycle)
Typical Applications
- Conveyor and material handling systems requiring pilot-duty solenoid switching
- Valve and actuator control with integrated fault diagnostics
- Safety-adjacent circuits with per-point output monitoring
- Pump and motor starter logic in packaging, food processing, and automotive manufacturing
- Industrial machinery requiring real-time detection of open-load and short-load faults
Compatibility & Replacements
The 1756-OB16D is a chassis-mount module compatible with all standard ControlLogix 1756 chassis. Direct slot interchange (no chassis modification required) makes it a drop-in replacement for other 16-point diagnostic output modules in the same family. Installation requires a 36-position removable terminal block housing (RTB)—either the 1756-TBCH or 1756-TBS6H—sold separately. The module is fully compatible with Studio 5000 (formerly RSLogix 5000) development software and current ControlLogix firmware. EDS files and Add-On Profiles are available from Rockwell Automation’s technical documentation center. Always verify chassis power budget before mixed-module configurations.
