1794-OC16 Allen Bradley Flex I/O 16 Channel Sourcing Output Module

1794-OC16 High-Density Sourcing Output Architecture

The 1794-OC16 is a high-density, 16-channel digital DC sourcing output module engineered for the Allen-Bradley Flex I/O Series by Rockwell Automation. Built specifically for driving higher-voltage DC actuators, this unit delivers current-sourcing outputs rated for a nominal 48V DC line (operating range 30 to 60V DC, including 5% AC ripple). It accommodates up to 500 mA per channel, enabling an aggregate module load capacity of 8.0 A. High-speed solid-state switching logic achieves rapid signal propagation with an OFF-to-ON response time of ≤0.5 ms and an ON-to-OFF response time of ≤1.0 ms at 25 °C (≤2.0 ms at 55 °C). The module plugs into terminal base units including 1794-TB2, 1794-TB3, 1794-TB3S, 1794-TB3K, and 1794-TB3SK set to Keyswitch Position 2, drawing a low 80 mA from the 5V DC Flexbus backplane while providing 1900V DC isolation between user-side power and system logic for 1 second.

Technical Specifications Summary

Target Equipment & Field Integration Scenarios

The 48V DC sourcing configuration of the 1794-OC16 serves industrial applications where 48V control buses are preferred to reduce line losses over extended cable lengths:

• Telecommunications control systems and DC power backup automation panels operating on 48V DC buses
• Direct driving of 48V DC solenoid valves, pneumatic manifolds, and directional hydraulic coils
• Interfacing with high-voltage DC relays and heavy-duty contactor coils in utility sub-panels
• Actuating 48V industrial warning beacons, horns, and stack light indicators across large facilities
• Sourcing current to automated sorting line gates and high-speed material handling actuators

Diagnostic Visuals & Channel Sourcing Protection

Built-in logic indicators and transient protection ensure reliable field control and rapid diagnostic troubleshooting:

• Field-Side Status LEDs: Sixteen logic-driven yellow LEDs located on the front panel illuminate directly when corresponding output logic gates are active.
• High Surge Capacity: Every output channel tolerates a 4.0 A surge for up to 10 ms, allowing direct switching of inductive loads with high initial inrush current.
• Optically Isolated Backplane: Field-side power rails are galvanically separated from the internal Flexbus logic network up to 1900V DC.

Packaging, Express Logistics & Warranty Terms

• Item Condition: Factory Sealed, Brand New Original Stock
• Warranty Coverage: Backed by a 12 Months Replacement Guarantee
• Order Processing: Dispatches within 24–48 hours upon order verification
• Global Express Carriers: Direct door-to-door transit via FedEx, UPS, or DHL

Global PLC Spare HUB's Insight

The 1794-OC16 is a current-sourcing module, meaning it connects the positive +48V DC side of the supply to the output terminal when activated; field loads must have their opposite lead connected to the DC common rail. Because all 16 channels share a single internal DC power rail without channel-to-channel isolation, an accidental short on one output line can blow the main branch fuse or trip the power supply, affecting adjacent channels. When wiring inductive loads such as 48V solenoids or large relay coils, always install external flyback diodes across field load terminals. This suppresses back-EMF voltage spikes upon coil de-energization, protecting internal solid-state output transistors from over-voltage degradation and extending module service life.

Frequently Asked Questions (FAQ)

Q: What field wiring behavior occurs if a current-sinking sensor or load is wired to an output channel on this module?

A: Sourcing output channels supply positive voltage (+48V DC) out to the field; connecting a current-sinking output to another sourcing circuit will create a direct short circuit or prevent the load from energizing until wired to the DC negative return line.

Q: Does operating the module at elevated temperatures affect the maximum allowable DC voltage input?

A: Yes; the module accepts up to 60V DC maximum at ambient temperatures up to 45 °C, but the maximum allowable supply voltage drops to 55V DC when operating in environments between 45 °C and 55 °C to prevent internal thermal overload.

Q: How can branch current protection be implemented on individual field lines for this sourcing output card?

A: Install inline 2.0 A, 150V AC MQ2 normal-blow fuses on field supply lines or use a fused base assembly to prevent high short-circuit currents from damaging the 500 mA output transistors.

Q: Why is there an OFF-to-ON response time advantage on this DC module compared to AC output cards?

A: Solid-state DC output transistors switch almost instantaneously (≤0.5 ms delay) because they do not have to wait for an AC sine wave zero-crossing event, making this card ideal for high-speed automated packaging lines.

Q: Selection Guide: How do I choose between specifying the 1794-OC16 sourcing module and a 24V DC module like the 1794-OB16?

A: Select the 1794-OC16 when field control actuators and power buses operate on 48V DC nominal voltage (30…60V DC range). Select the 1794-OB16 when field solenoids and control circuits operate on standard 24V DC nominal power (10…31.2V DC range).

Tags