Allen-Bradley 1756-ON8 ControlLogix Output Module

1756-ON8 Allen-Bradley ControlLogix AC Output Module

Product Introduction

The Allen-Bradley 1756-ON8 is a digital AC output module engineered for the ControlLogix 1756 chassis. This module provides 8 output points organized into two groups of four, making it suitable for controlling AC loads such as motor starters, solenoids, and pilot lights. Its operating voltage range spans 10 to 30V AC at 50-60 Hz, with a nominal rating of 24V AC. Furthermore, the 1756-ON8 employs a producer/consumer communication model, enabling efficient data exchange and flexible system configuration.

Technical Specifications

The 1756-ON8 delivers reliable AC output switching with clearly defined electrical parameters. Its backplane current consumption is 200 mA at 5V DC, with a total backplane power of 1.07 W. The maximum power dissipation reaches 5.1 W at 60°C, while thermal dissipation is rated at 17.39 BTU/hr.

Key Output Characteristics:

• Number of Outputs: 8 (4 points per group)

• Voltage Category: 24V AC (50-60 Hz)

• Operating Voltage Range: 10 – 30V AC

• Current per Point: 2 Amps maximum at 60°C

• Current per Module: 5 Amps at 30°C; 4 Amps at 60°C

• Isolation Voltage: 50 Volts (continuous)

• On/Off Delay Time: 9.3 ms at 60 Hz; 11 ms at 50 Hz

Communication and System Integration

The 1756-ON8 integrates seamlessly into the ControlLogix architecture. It supports both direct connections and rack-optimized connections, providing flexibility in system design. Direct connections offer dedicated communication between the module and the controller, while rack-optimized connections reduce the communication overhead by consolidating data from multiple modules.

Additionally, this module uses the producer/consumer model, which allows it to multicast data to multiple controllers simultaneously. This feature enhances system efficiency and reduces network traffic, particularly beneficial in large-scale distributed control systems.

Mechanical and Environmental Specifications

The Allen-Bradley 1756-ON8 is built to operate reliably in demanding industrial environments. It functions within a temperature range of 0 to 60°C and can withstand 30g of operating shock. When not in operation, it tolerates temperatures from -40 to 85°C and shock levels up to 50g. Its relative humidity range is 5-95% noncondensing, ensuring performance in humid conditions.

Moreover, this module features an open-type enclosure, requiring installation within a protective cabinet. Compatible removable terminal blocks include the 1756-TBSH (screw-type) and 1756-TBNH (spring-type), both offering secure field wiring connections. Front-panel LED indicators provide real-time status for each output point and overall module health.

Installation Guidelines

Proper installation of the 1756-ON8 ensures safe and reliable operation in your ControlLogix system.

1. Chassis Selection: First, confirm that the ControlLogix chassis has an available slot and adequate power budget.

2. RTB Attachment: Next, attach the appropriate RTB (1756-TBSH or 1756-TBNH) to the module's front connector.

3. Module Insertion: Then, insert the module into the selected slot and secure it by tightening the retaining screws.

4. Wiring: After that, connect the AC load devices to the RTB terminals, adhering to the specified wiring diagrams and torque requirements.

5. Configuration: Finally, configure the module's communication settings in the Logix Designer application, selecting either direct or rack-optimized connections as needed.

Important Safety and Application Notes

Do not disconnect this equipment unless power has been completely shut off. Secure all external connections using the provided screws, shear hooks, or threaded connectors. Exceeding the surge and power ratings when applying this module to devices in its network can result in damage. The 1756-ON8 is designed as a component of a ControlLogix system, which also includes controllers and adapters. Shutting off power to the chassis is not mandatory for module removal or installation, as these operations do not disrupt other processes in the system.

Packaging List

Each shipment of the Allen-Bradley 1756-ON8 includes the following items:

• 1 x Digital AC Output Module

• 1 x Installation Instructions manual
  (Note: Removable Terminal Block is sold separately.)

Frequently Asked Questions (FAQ)

1. What voltage and frequency does the 1756-ON8 output module support?
The Allen-Bradley 1756-ON8 supports 24V AC at 50-60 Hz, with an operating voltage range of 10 to 30V AC.

2. How many outputs does the 1756-ON8 provide?
This module provides 8 output points, organized into two isolated groups with 4 points per group for flexible load control.

3. Which removable terminal blocks are compatible with the 1756-ON8?
The 1756-ON8 works with either the 1756-TBSH (screw-type) or the 1756-TBNH (spring-type) removable terminal blocks.

4. Can I install or remove the 1756-ON8 while the system is powered on?
Yes, the Allen-Bradley 1756-ON8 supports removal and installation under power (RIUP), allowing you to replace modules without disrupting other system processes.

5. What shipping carriers do you use for the 1756-ON8 module?
We ship this product using reliable global carriers such as FedEx, UPS, and DHL to ensure safe and timely delivery.