Product Overview
The Allen-Bradley 1790-T0A8X is a 120V AC 8 Output Base Module designed for industrial control systems that require reliable switching of AC loads. This module provides eight nonisolated output points, each capable of handling load voltages from 15 to 132V AC rms and a maximum load current of 0.5A rms. With a compact form factor and straightforward wiring, the 1790-T0A8X integrates seamlessly into existing automation architectures, offering dependable performance for a variety of applications.
Built with photocoupler isolation between I/O and logic, the 1790-T0A8X ensures safe operation while maintaining signal integrity. The module includes 8 green status indicators for quick visual diagnostics, and its terminal block (M3.0) simplifies field wiring. Whether you are upgrading legacy systems or designing new control panels, the 1790-T0A8X delivers the robustness and precision required for demanding industrial environments.
Technical Specifications
The following table outlines the key electrical and mechanical specifications of the Allen-Bradley 1790-T0A8X, sourced directly from the manufacturer's data:
| Attribute |
Value |
| Outputs per expansion module |
8 points nonisolated |
| Load voltage range |
15…132V rms |
| Load current, max |
0.5 A rms |
| Load current, min |
10 mA rms |
| Off-state leakage current, max |
1.0 mA rms @ 100V rms 60 Hz |
| On-state voltage drop, max |
1.3V rms @ max load |
| Operate time, max |
1 ms |
| Release, max |
1/2 cycle + 1 ms |
| Insulation resistance |
Min 1,000 MΩ (for input-output) |
| Dielectric strength |
2500V rms 1 minute (for input-output) |
| Indicators |
8 green input status |
| Common type |
8 points/8 COM |
| External AC power supply – Supply voltage |
110V rms, 60 Hz |
| Voltage range |
15…132V rms, 60 Hz |
| Power dissipation |
5.2 W @ rated current |
| Isolation I/O to logic |
Photocoupler isolation, 1250V ac rms/V ac |
| Field power isolation |
Non-isolation |
| Wiring |
Terminal block (M3.0), screw torque: 7 lb-in max (use copper or copper-clad aluminum conductors) |
| Weight |
3.00 lbs (1.36 kg) |
Industry Applications
The 1790-T0A8X excels in applications where reliable AC output switching is critical. In packaging lines, it controls solenoid valves and motor starters, ensuring precise timing and repeatability. In HVAC systems, the module manages fans and dampers, maintaining optimal environmental conditions. Additionally, in material handling equipment, the 1790-T0A8X drives conveyor motors and warning lights, contributing to smooth operations and enhanced safety.
Because the module supports a wide load voltage range (15…132V AC) and offers fast operate time (1 ms), it suits high-cycle applications where rapid response is essential. Its robust isolation and dielectric strength (2500V AC) provide an extra layer of protection in electrically noisy environments, reducing the risk of false triggering and equipment damage.
Installation & Setup Guidance
Wiring the 1790-T0A8X is straightforward. Connect 120V AC field power to V AC (pin 1) and COM (pin 2). Note that all V AC pins are internally connected, as are all COM pins, simplifying daisy-chaining. Use copper or copper-clad aluminum conductors and tighten terminal screws to a maximum torque of 7 lb-in to ensure secure connections.
Mount the module on a standard DIN rail or panel, ensuring adequate ventilation for heat dissipation. The module's compact design allows for high-density mounting, but maintain a minimum clearance of 50 mm above and below for airflow. Verify that the external AC power supply meets the specified voltage range (15…132V AC, 60 Hz) before energizing the module.
Maintenance & Reliability
Routine maintenance of the 1790-T0A8X is minimal but essential for long-term reliability. Periodically inspect the terminal block connections for tightness and signs of corrosion. Check the status indicators to confirm proper operation; a green light on each output indicates an active channel. In dusty or humid environments, clean the module enclosure with a dry, lint-free cloth to prevent contamination.
Because the module uses photocoupler isolation, it is inherently protected against voltage spikes and transients, reducing wear on internal components. With proper care, the 1790-T0A8X offers years of dependable service, minimizing downtime and lowering total cost of ownership.
Compatibility & Integration
The 1790-T0A8X is part of the Allen-Bradley 1790 series, designed to work with a wide range of industrial controllers and I/O systems. It integrates easily with Allen-Bradley Programmable Logic Controllers (PLCs) and can be used in distributed I/O configurations. The module's 8-point output configuration is compatible with standard wiring practices, making it a versatile choice for both new installations and retrofits.
When integrating the 1790-T0A8X into an existing system, verify that the controller's output addressing matches the module's channel mapping. The module's nonisolated outputs are suitable for applications where all outputs share a common return, simplifying wiring and reducing component count.
Buying Guide
Before purchasing the 1790-T0A8X, confirm your system's voltage and current requirements against the module's specifications. Ensure your load is within the 15…132V AC range and does not exceed 0.5A per channel. Also, verify that your controller supports the module's wiring configuration and that you have the necessary terminal blocks and conductors.
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