Product Overview

The Allen-Bradley 1746-OV8​ is an eight-channel DC digital output module from the SLC 500 family of Rockwell Automation, built to switch 24V DC field devices directly from a single slot of an SLC 500 chassis. As a current-sinking output module, the Allen-Bradley 1746-OV8​ completes the load circuit to the DC common, which matches the wiring practice most North American and European panels already follow for solenoid valves, relay coils, indicator lamps, small contactors and alarm annunciators, so no additional interposing hardware is required between the PLC and the load.One of the practical strengths of the Allen-Bradley 1746-OV8​ is its unusually wide operating voltage range of 10 to 50V DC, which means the same module can serve 12V, 24V and 48V DC control circuits simply by changing the supply connected to the group. Each of the eight outputs is rated for 1.0 A continuous at 30 °C and 0.5 A at 60 °C, with a module total of 8.0 A and 4.0 A respectively, and each point tolerates a 3 A surge for 10 milliseconds to absorb lamp inrush and solenoid pull-in current. Switching is fast, with a 0.1 ms off-to-on delay and a 1.0 ms on-to-off delay into a resistive load, which is more than adequate for discrete machine sequencing and interlocking.In day-to-day operation, the Allen-Bradley 1746-OV8​ is designed for clarity and serviceability. Eight front-panel LEDs show the live state of every output point, colour-coded removable terminal blocks with self-lifting pressure plates accept up to two 14 AWG conductors per terminal, and compatibility with the Bulletin 1492 pre-wired cable system lets panel builders replace hand-terminated wiring with plug-in harnesses. The module installs in any SLC 500 local, expansion or remote I/O chassis slot, drawing 135 mA at 5V DC from the backplane, and requires no user configuration beyond normal I/O addressing in RSLogix 500.

Technical Specifications

Main Features and Advantages

Wide voltage range that reduces spares variety: The Allen-Bradley 1746-OV8​ operates anywhere between 10 and 50V DC, so the same catalogue number covers 12V, 24V and 48V DC control circuits. Maintenance departments can standardise on a single spare module across machines that use different control voltages, which lowers inventory cost and removes the risk of fitting a wrong-voltage output card during an urgent repair.Strong per-point current with honest derating: Each channel of the Allen-Bradley 1746-OV8​ delivers 1.0 A continuously at 30 °C, sufficient for solenoid valves, relay coils, indicator columns and small contactor coils, while a 3 A surge rating for 10 milliseconds absorbs the inrush of incandescent lamps and inductive devices. The published derating to 0.5 A per point and 4.0 A per module at 60 °C is not a limitation but a design aid: it lets the engineer size loads correctly for hot cabinets instead of discovering a thermal problem after commissioning.Fast, predictable switching: With a 0.1 ms turn-on and 1.0 ms turn-off delay, the Allen-Bradley 1746-OV8​ is far faster than any relay output module and comfortably handles high-speed discrete sequencing, interlocks and alarm driving without adding measurable latency to the SLC scan.Serviceability built into the hardware: Eight front-panel LEDs on the Allen-Bradley 1746-OV8​ let a technician confirm in seconds whether the processor has commanded an output and whether the output device is responding, which is often enough to distinguish a blown solenoid coil from a logic fault. Colour-coded removable terminal blocks mean the module can be replaced without disturbing field wiring, and 1492 pre-wired cables further cut panel build time and wiring errors.Simple integration: The Allen-Bradley 1746-OV8​ needs no DIP switches, jumpers or configuration words. It is addressed as a standard discrete output module in RSLogix 500, fits any I/O slot, and its 135 mA backplane draw at 5V DC keeps the chassis power budget easy to manage even in fully populated racks.