Product Overview
The Allen-Bradley 1790-T0W8X is an 8 relay output expansion module designed for industrial automation systems. This component provides eight discrete relay outputs with Form A (normally open) single-pole single-throw contacts. It expands the I/O capacity of compatible controllers, enabling reliable switching of various loads in manufacturing and process environments.
Technical Specifications Breakdown
Key parameters for the 1790-T0W8X are listed below for quick reference:
| Feature | Specification |
|---|---|
| Output Type | Relay, Form A (normally open), SPST |
| Number of Channels | 8 |
| Output Voltage Range (load dependent) | 5…28V dc @ 2.0 A resistive; 48V ac @ 0.8 A resistive; 125V ac @ 2.0 A resistive; 250V ac @ 2.0 A resistive |
| Minimum Load | 100 µA, 100mV dc per input |
| On-State Voltage Drop (max) | 0.5V @ 2.0 A, resistive load, 24V dc |
| Initial Contact Resistance | 30 mΩ |
| Expected Contact Life (resistive) | 300 Kcycles |
| Expected Contact Life (inductive) | 100 Kcycles |
| Off-State Leakage (max) | 1.5 mA max |
| Output Delay Time | Off to On: 10 ms max; On to Off: 10 ms max |
| Indicators | 8 green status |
| Common Type | 1 point/1COM |
| Field Power Supply Voltage | 24V dc nom |
| Voltage Range | 19.2…28.8V dc |
| Power Dissipation | 2.3W @ 28.8V dc per channel |
| Isolation | I/O to logic: photocoupler isolation; Isolation voltage: 1250V ac rms |
| Wiring | Terminal block (M3.0); screw torque: 7 lb-in max (use copper or copper-clad aluminum conductors) |
| Weight | 0.38 lbs (0.17 kg) |
Industry Applications
Common uses include controlling motor starters, solenoid valves, and indicator lights. In packaging lines, the 1790-T0W8X switches actuators and conveyors reliably. Its wide AC/DC voltage range makes it versatile for global installations. The 300 Kcycle resistive contact life ensures long service in high-cycle applications, reducing downtime and replacement costs.
Installation & Setup Guidance
Mount the module securely in a suitable enclosure. Use copper or copper-clad aluminum conductors for wiring. Tighten terminal block screws to 7 lb-in maximum. Connect field power within 19.2…28.8V DC. Ensure the load does not exceed the specified voltage and current ratings. Verify that the isolation voltage (1250V AC rms) is adequate for your system. Always follow the controller's manual for addressing and configuration.
Maintenance & Reliability
Inspect the module periodically for loose connections or signs of overheating. Clean the enclosure to prevent dust accumulation. The relay contacts have a finite life; monitor switching cycles in high-usage applications. Replace the module if output delays increase beyond 10 ms or if contact resistance rises significantly.
Compatibility & Integration
The 1790-T0W8X is an expansion module for compatible Allen-Bradley systems. It integrates via the terminal block interface. No additional communication protocols are required for basic operation. Verify compatibility with your specific controller model before installation.
Selection Guide & Purchasing Advice
Choose the 1790-T0W8X when you need eight relay outputs with Form A contacts. Evaluate your load voltage and current requirements against the specifications. For assistance, contact AutoDCSTech to confirm availability and lifecycle status.
Troubleshooting & Common Issues
If outputs fail to switch, check the field power supply voltage (19.2…28.8V DC). Verify wiring integrity and screw torque. If the green status indicators are off, the module may not be receiving power or communication. For intermittent faults, inspect for loose connections or contact wear. Do not exceed the specified load ratings.
Availability & Condition at AutoDCSTech
| Part Number | 1790-T0W8X |
|---|---|
| Availability | In Stock |
| Condition | New |
| Warranty | One Year |
| Origin | US |
