Allen-Bradley 1746-OA16 PLC Output Module

Product Details

1746-OA16 Product Description

The Allen-Bradley 1746-OA16 is a 16-point, 120/240VAC discrete output module engineered for seamless integration within the SLC 500 modular control platform. Designed to deliver reliable field-side switching across demanding industrial environments, the 1746-OA16 occupies a standard 1746 I/O chassis slot and communicates directly with the SLC 5/03, SLC 5/04, and SLC 5/05 processor families through the SLC 500 backplane. Its triac-based AC output design eliminates mechanical wear, reduces maintenance intervals, and supports high-cycle applications in manufacturing, utilities, and process control. With a per-point output current rating of 0.5A continuous and a surge capacity of 7.5A for 43ms, the module is well-suited for driving solenoid valves, motor starters, pilot lights, and small actuator loads. Each output is individually fused and optically isolated, ensuring that a field-side fault does not propagate into the control backplane — a critical requirement in safety-sensitive and high-availability architectures. The 1746-OA16 ships pre-tested, carries a 12-Month Warranty, and is stocked for immediate dispatch to minimize unplanned downtime on your production line.

The 1746-OA16 does not operate in isolation — its value is fully realized when deployed as part of a coherent SLC 500 control architecture. At the processor layer, the Allen-Bradley SLC 5/04 (1747-L541) or SLC 5/05 (1747-L551) CPU manages ladder logic execution and coordinates all I/O data across the 1746 backplane. The processor reads output image table bits and drives the 1746-OA16 output points in each scan cycle, enabling deterministic control of field devices with sub-millisecond response at typical program sizes.

On the input side, the 1746-IA16 (16-point 120VAC discrete input module) pairs directly with the 1746-OA16 to form a complete AC I/O layer within the same chassis. For mixed-signal applications, the 1746-NI4 analog input module or 1746-NO4I analog output module can be added to the same rack, allowing the SLC 5/04 to handle both discrete switching and continuous process variable control from a single backplane — a common requirement in pump stations, HVAC systems, and batch processing lines.

Power integrity across the 1746 chassis is maintained by the 1746-P4 power supply, which delivers regulated 5VDC backplane power and 24VDC auxiliary output. In larger installations using multiple chassis, the 1746-P7 extended-capacity supply ensures that high-density I/O racks — including those populated with multiple 1746-OA16 modules — remain within safe thermal and electrical operating margins. Proper power budgeting across the chassis is essential when the 1746-OA16 is used at full 16-point load with inductive AC loads, as inrush currents must be accounted for in the supply selection.

For remote I/O expansion beyond the local chassis, the 1747-SN Remote I/O Scanner or 1747-ASB Adapter module extends the SLC 500 I/O network to remote racks, allowing 1746-OA16 modules to be distributed across the plant floor while remaining under centralized processor control. This architecture is widely used in conveyor systems, packaging lines, and multi-zone process plants where field devices are geographically dispersed. Communication integrity on the remote I/O link is maintained through proper termination resistors and shielded cable runs, ensuring that output switching commands arrive without signal degradation.

At the HMI layer, a PanelView 550 (2711-B5A8) or PanelView Plus 600 terminal connected via DH-485 or DH+ provides operators with real-time visibility into output states driven by the 1746-OA16. Alarm annunciation, output force commands, and diagnostic status can be surfaced directly on the HMI, reducing mean time to repair during fault conditions. For Ethernet-connected supervisory systems, the 1747-AENTR EtherNet/IP adapter bridges the SLC 500 backplane to a SCADA or MES layer, enabling the 1746-OA16 output states to be logged, trended, and alarmed at the enterprise level.

In safety-critical or high-availability applications, the 1746-OA16 is often deployed alongside 1746-OBP8 DC output modules in a mixed-output chassis, where AC loads (solenoids, motor starters) and DC loads (24VDC relays, sensors) are segregated by module type but managed by the same processor. This mixed-output strategy simplifies cabinet wiring, reduces the number of intermediate relays, and improves overall system diagnostics by keeping all output states visible in a single I/O image table.

Manufacturing & Assembly Lines: In automotive and electronics assembly, the 1746-OA16 drives pneumatic solenoid valves, conveyor motor starters, and fixture clamps under SLC 5/04 control. Its triac output eliminates contact bounce and arc erosion, extending the service life of field devices in high-cycle environments where output switching may exceed one million operations per year. The module's individual point isolation prevents a shorted solenoid from taking down adjacent outputs, maintaining partial line operation during fault recovery.

Power & Utilities: In substation automation and electrical distribution panels, the 1746-OA16 controls AC-operated circuit breaker trip coils, alarm horns, and indicator lamps. The wide 85–265VAC input range accommodates both 120VAC and 240VAC field wiring without module substitution, simplifying spare parts management across multi-voltage facilities. Combined with the SLC 5/05 processor's Ethernet connectivity, the output states can be monitored remotely by SCADA systems for real-time grid status reporting.

Water & Wastewater Treatment: Pump stations and filtration plants rely on the 1746-OA16 to switch AC motor starters for raw water pumps, chemical dosing pumps, and UV disinfection systems. The module's solid-state design is particularly advantageous in humid, corrosive environments where mechanical relay contacts are prone to oxidation. Paired with the 1746-IA16 input module monitoring float switches and flow sensors, the SLC 500 system delivers closed-loop pump control with automatic lead-lag sequencing.

Oil, Gas & Petrochemical: In wellhead automation and pipeline control, the 1746-OA16 operates within purged and pressurized enclosures to switch AC-powered shutdown valves, flare ignition systems, and compressor motor starters. The optical isolation between field and logic sides is a mandatory requirement in Class I, Division 2 hazardous locations, where field-side transients must be prevented from reaching the control backplane. The module's 12-Month Warranty and documented test records support the rigorous maintenance documentation requirements of oil and gas operators.

Packaging & Material Handling: High-speed packaging lines use the 1746-OA16 to control AC-driven labelers, heat sealers, reject gates, and accumulation conveyor drives. The module's 7.5A surge rating accommodates the inrush current of small AC motors and transformer-coupled loads without nuisance tripping, while the 0.5A continuous rating is sufficient for the majority of solenoid and pilot light loads encountered in packaging machinery.

Q1: Is the 1746-OA16 compatible with all SLC 500 chassis and processor generations?The 1746-OA16 is compatible with all standard 1746 chassis (1746-A4, A7, A10, A13) and all SLC 500 processor families including the SLC 5/01 through SLC 5/05. It occupies a single I/O slot and is recognized automatically by the processor during the I/O configuration scan. No special firmware or configuration file is required beyond assigning the correct slot address in RSLogix 500. For systems using the SLC 5/05 with EtherNet/IP, the output states of the 1746-OA16 are accessible via MSG instructions to remote SCADA or HMI systems without additional hardware.

Q2: What are the key considerations when mixing 1746-OA16 modules with DC output modules in the same chassis?When mixing AC and DC output modules in a 1746 chassis, the primary considerations are power supply capacity, wiring segregation, and I/O image table organization. The 1746-P4 or 1746-P7 power supply must be sized to cover the combined backplane current draw of all installed modules. AC and DC field wiring should be routed in separate cable trays to prevent inductive coupling and noise injection. In RSLogix 500, output addresses are assigned sequentially by slot, so mixed-output racks require careful address mapping to ensure that AC and DC outputs are not inadvertently interchanged during program development or maintenance.

Q3: What does the 12-Month Warranty cover, and how does NANKMOS support long-term spare parts availability?The 12-Month Warranty covers manufacturing defects, premature component failure, and functional non-conformance under normal operating conditions as specified in the Allen-Bradley 1746-OA16 product documentation. Each unit shipped by NANKMOS undergoes pre-shipment functional testing to verify output switching, optical isolation integrity, and backplane communication compatibility. For long-term maintenance planning, NANKMOS maintains stocked inventory of the 1746-OA16 and related 1746 series modules to support emergency replacement, scheduled overhaul, and multi-unit sparing programs. Contact [email protected] or +86 18359268345 for availability confirmation and lead time on volume orders.