Application Scenarios

A bottling plant operates a high-speed filling line controlled by an SLC 5/04 processor. The existing output modules have become unreliable, with occasional channel failures causing unplanned line stoppages. The maintenance team suspects the failures stem from inductive kickback generated by solenoid valves that are not properly suppressed.

The engineering team replaces the aging modules with a 1746-OB16 in the main I/O chassis. The sixteen output channels control solenoid valves, indicator lamps, and relay coils throughout the filling station. With a per-point continuous current rating of 0.5A at 30°C, the 1746-OB16 handles the combined load of multiple solenoids without derating concerns . The module’s built-in electronic protection (E-Fuse) limits current on any channel experiencing a short circuit or overload, allowing other channels to continue operating normally . This fault isolation feature prevents a single solenoid failure from shutting down the entire filling line. The E-Fuse LED on the front panel provides immediate visual indication of the affected channel, reducing troubleshooting time from hours to minutes.

 

Parameter

Main Parameters	Value/Description
Product Model	1746-OB16
Manufacturer	Allen-Bradley / Rockwell Automation
Product Category	Digital DC Output Module
Series	SLC 500
Number of Outputs	16 (single group)
Output Type	Current Sourcing (positive switching)
Nominal Output Voltage	24VDC
Operating Voltage Range	10-50VDC
Continuous Current per Point	0.5A @ 30°C; 0.25A @ 60°C
Continuous Current per Module	8A @ 30°C; 4A @ 60°C
Backplane Current	0.280A @ 5.1VDC
Output Delay (OFF to ON)	1.0 ms
Output Delay (ON to OFF)	0.1 ms
Off-State Leakage Current	1 mA maximum
Isolation	1500VAC between backplane and outputs
Dimensions	Single-slot SLC 500 module
Operating Temperature	0°C to +60°C
Mounting	SLC 500 chassis (any slot except leftmost)

 

 

Technical Principles and Innovative Values

Innovation Point 1: High-Density Output Control in a Single Slot. The 1746-OB16 packs sixteen independently controlled DC outputs into a single SLC 500 slot, maximizing I/O density within the chassis. This high-density design is particularly valuable in applications where panel space is limited but numerous field devices require control, such as multi-zone conveyor systems or complex packaging machinery with multiple actuators.

Innovation Point 2: Integrated Electronic Protection with Auto-Reset. The 1746-OB16 features an electronic fuse (E-Fuse) that provides current overload and short-circuit protection on a per-channel basis . When a channel experiences a fault, the module limits current to that channel while allowing unaffected channels to continue operating. Once the fault condition clears, the channel automatically resets without requiring manual intervention. The E-Fuse LED on the front panel illuminates during fault conditions, enabling rapid identification of problem channels.

Innovation Point 3: Fast Switching Response for High-Speed Applications. With an OFF-to-ON delay of 1.0 ms and an ON-to-OFF delay of 0.1 ms, the 1746-OB16 supports responsive control of high-speed sorting, indexing, and positioning applications . The load-dependent delay times ensure predictable switching performance even with varying load characteristics.

Innovation Point 4: Broad Operating Voltage Range. The 1746-OB16 accepts field supply voltages from 10 to 50VDC, providing flexibility in power distribution design . This wide range accommodates both standard 24VDC industrial power and higher voltage applications, reducing the need for separate power supplies in mixed-voltage control systems.