Product Introduction
The Allen-Bradley 1746-OB16 is a Digital DC Output Module from the SLC500 series, designed to drive high-current DC loads in industrial control systems. With sixteen (16) outputs in a single group, this module delivers a 24VDC output signal with an operating voltage range of 10–30VDC. Built by Rockwell Automation, the 1746-OB16 ensures robust switching performance, making it a cost-effective choice for applications requiring reliable on/off control of solenoids, relays, and indicator lights. Its compact design minimizes panel space while maximizing output density, contributing to lower total cost of ownership over the module's service life.
When system downtime or component failure threatens production, the 1746-OB16 offers a proven solution. Its solid-state design reduces wear compared to electromechanical relays, and the low heat dissipation (7.6 Watts) simplifies thermal management in crowded enclosures. By selecting the Allen-Bradley 1746-OB16, you invest in a module that balances performance with longevity, reducing maintenance intervals and spare parts inventory.
Technical Specifications
Below are the key parameters for the Allen-Bradley 1746-OB16. All values are sourced directly from the product datasheet and are guaranteed by Rockwell Automation.
| Parameter |
Value |
| Number of Outputs |
16 (sixteen) |
| Output Voltage |
24 VDC |
| Operating Voltage Range |
10–30 VDC |
| Output Delay OFF→ON |
1.0 ms |
| Output Delay ON→OFF |
0.1 ms |
| OFF‑State Leakage Current |
1 mA |
| Backplane Current at 5.1 V |
0.135 A |
| Continuous Current per Point |
1.5 A @ 30°C / 1.0 A @ 55°C |
| Continuous Current per Module (max) |
6.4 A @ 0…60°C |
| Voltage Range (Source) |
10–50 VDC |
| Current per Output |
0.5 A or 0.25 A |
| Current per Module |
8 A or 4 A |
| Backplane Current (5 V) |
280 mA |
| Current/Module @30°C |
9 A |
| Heat Dissipation |
7.6 W |
| Step Response (In/Out) |
60 ms in / 2.5 ms out |
| Applications |
High Current |
The high continuous current per point (1.5 A at 30°C) and low heat dissipation make the 1746-OB16 ideal for densely packed cabinets. The fast ON→OFF delay (0.1 ms) ensures precise timing in sequenced operations, reducing wear on downstream actuators.
Industry Applications
The Allen-Bradley 1746-OB16 excels in high‑current discrete control tasks. Common applications include:
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Packaging machinery – driving solenoids and actuators that handle high inrush currents. The module's ability to deliver 1.5 A per point reduces the need for external interposing relays.
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Material handling systems – controlling motor starters and conveyor diverters. The rugged output stage withstands frequent on/off cycles without degradation.
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Automotive assembly lines – switching weld guns and pneumatic valves. The 24VDC output matches standard industrial supply voltages, simplifying integration.
By choosing the 1746-OB16, manufacturers benefit from reduced downtime and lower spare parts cost compared to relay‑based solutions. The solid‑state outputs have a longer electrical life, directly improving ROI.
Maintenance & Reliability
The Allen-Bradley 1746-OB16 requires minimal routine maintenance. Because it uses transistor outputs rather than mechanical contacts, there are no moving parts to wear out. However, periodic inspections should include:
- Checking the backplane current draw (0.135 A at 5.1 V) to ensure the power supply is not overloaded.
- Verifying that ambient temperature remains within 0…60°C to avoid derating the continuous current per point.
- Inspecting connector pins for oxidation or looseness, especially in high‑vibration environments.
With proper care, the 1746-OB16 delivers reliable service for years. Its low heat dissipation (7.6 W) reduces thermal stress on adjacent modules, further extending overall system life.
Troubleshooting & Common Issues
When diagnosing problems with the 1746-OB16, consider these typical scenarios:
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Output fails to turn on – Verify that the backplane power is present and the module is properly seated. Check the load voltage – it must be within 10–50 VDC source for correct operation.
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Excessive leakage current – The leakage current is specified at 1 mA max. If a connected device (e.g., a small relay) does not release, add a bleed resistor across the load.
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Overheating – If the module exceeds 60°C, reduce the continuous load per point or improve cabinet ventilation. The module's current rating is temperature‑dependent.
Always reference the SLC500 installation manual for detailed troubleshooting steps. The 1746-OB16’s internal diagnostics help identify open‑circuit or short‑circuit conditions quickly.
Selection Guide & Purchasing Advice
Before purchasing the Allen-Bradley 1746-OB16, confirm that your system supports SLC500 series I/O modules. Check the backplane power budget – the module draws 280 mA at 5 V, which must be within your chassis capacity. Also verify the output wiring: the module provides sourcing DC outputs, so your loads must be connected between the output and common (DC‑).
UBEST Automation offers the 1746-OB16 as a genuine Rockwell Automation product, backed by our quality assurance. Visit ubest101.myshopify.com to check current inventory and pricing. For bulk orders or expedited shipping, contact our sales team directly.