Product Overview
When your SLC 500 system demands reliable switching across mixed voltage levels, the Allen-Bradley 1746-OW8 delivers a robust solution. This Digital Contact Output Module provides eight (8) Normally Open (N.O.) relay channels, each capable of handling 5-265V AC or 5-125V DC. With two (2) output groups of four (4) channels per common, the 1746-OW8 lets you operate different voltage categories on a single module—eliminating the need for interposing relays and saving valuable panel space.
Key Features & Benefits
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Flexible Voltage Handling: Operates across 5-265V AC or 5-125V DC, accommodating diverse field devices.
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Two Independent Groups: Each group of 4 channels shares a common, allowing mixed voltage operation.
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High Current Capacity: 1.5 A per output at 120V AC and 1.2 A at 24V DC, with a continuous module current of 16 A AC (8 A per group).
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Fast Switching: Step response of 60 ms in and 2.5 ms out, with signal delays of 10.0 ms for both ON and OFF transitions at maximum resistive load.
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Space-Saving Design: Occupies a single slot in the SLC 500 chassis, regardless of installation position.
Technical Specifications
| Specification |
Value |
| Manufacturer |
Rockwell Automation |
| Brand |
Allen-Bradley |
| Part Number |
1746-OW8 |
| Series |
SLC 500 |
| Module Type |
Digital Contact Output Module |
| Number of Outputs |
8 |
| Operating Voltage |
5-265V AC or 5-125V DC |
| Number of Groups |
2 |
| Points per Group |
4 |
| Output Type |
N.O. Relay Contact |
| Current per Output (120V AC) |
1.5 A |
| Current per Output (24V DC) |
1.2 A |
| Backplane Current |
0.85-0.9 A |
| Step Response |
60 ms in, 2.5 ms out |
| Signal Delay (Max Resistive Load) |
ON = 10.0 ms, OFF = 10.0 ms |
| Continuous Current per Module |
16.0 A AC (8.0 A per group) |
| Operating Temperature |
-25 to 60 °C (-13 to 140 °F) |
| Nonoperating Temperature |
-40 to 85 °C (-40 to 185 °F) |
| Relative Humidity |
5-95% without condensation |
| Operating Vibration |
2g at 10-500 Hz |
| Operating Shock |
30g |
| Heat Dissipation |
3.7 W max (0.138 W per point) |
| Backplane Current at 5V DC |
85 mA |
| Backplane Current at 24V DC |
90 mA |
Industry Applications
The Allen-Bradley 1746-OW8 is designed for use with SLC 500 programmable logic controllers, including fixed and modular configurations. It is compatible with SLC 5/01, 5/02, 5/03, 5/04, and 5/05 processors. Typical applications include:
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Motor and Valve Control: Switching AC or DC loads such as contactors, solenoids, and small motors in discrete manufacturing lines.
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Mixed-Voltage Systems: Controlling devices that operate at different voltage levels within the same panel, reducing the need for interposing relays.
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Remote I/O Installations: In remote I/O chassis, the 1746-OW8 can be placed in any slot other than slot 0, which is reserved for a communication adapter.
Installation & Setup Guidance
Install the 1746-OW8 in a suitable slot of your SLC 500 chassis. Ensure the power is removed before connecting or disconnecting any wiring. The module is supplied as open-type equipment and should be installed in an enclosure that provides protection against environmental contaminants. Maintain a pollution level no higher than Pollution 2 (as defined in EN/IEC 60664-1) when used in Zone 2 environments. Use only tools or appliances to access the enclosure, and never disconnect equipment in hazardous areas without de-energizing the circuit.
Maintenance & Reliability
Regularly inspect the module for signs of overheating, loose connections, or relay wear. The relay contacts are rated for 1.5 A at 120V AC and 1.2 A at 24V DC; exceeding these ratings can shorten relay life. Surge suppression devices can be added to protect against voltage spikes and extend the module's operational lifespan. Keep the enclosure clean and ensure proper airflow to maintain the operating temperature within -25 to 60 °C.
Compatibility & Integration
The 1746-OW8 integrates seamlessly with the SLC 500 platform, including fixed and modular processors. It supports remote I/O configurations, where it can be installed in any slot except slot 0. The module's two isolated groups allow you to connect loads with different voltage requirements, simplifying system design and reducing component count.
Selection Guide & Purchasing Advice
Before purchasing, verify that your SLC 500 chassis has an available slot and that the backplane current requirements (0.85-0.9 A) are within your system's capacity. Confirm the voltage and current ratings of your field devices to ensure they match the module's capabilities. For expert guidance and genuine Allen-Bradley 1746-OW8 modules, trust PLC Source PRO to supply reliable automation spares that keep your operations running.