Allen‑Bradley 1790D-T0W6 Relay Output Module

Allen‑Bradley 1790D-T0W6 6 Relay Output Base Module

Product Introduction

The 1790D-T0W6 from Allen‑Bradley is a compact DeviceNet base module with six independent relay outputs. Each relay is Form A, normally open, single‑pole single‑throw (SPST). You can use it with resistive loads up to 2.0A at voltage levels from 5V dc to 250V ac.

Meanwhile, this module supports both DC and AC field power. It requires a 24V dc nominal field supply, with a wide range of 19.2‑28.8V dc. The DeviceNet power also accepts 11‑28.8V dc.

Therefore, the 1790D-T0W6 fits many industrial switching tasks. For example, you can control contactors, pilot lights, or small relays. Additionally, the on‑state voltage drop is only 0.5V max at 2.0A, which reduces heat generation.

Technical Specifications (Relay Outputs)

• Output type: 6 relays, Form A (NO), SPST

• Output voltage range (load dependent):

  • 5…24V dc @ 2.0A resistive

  • 30V ac @ 2.0A resistive

  • 125V ac @ 2.0A resistive

  • 250V ac @ 2.0A resistive

• Output current rating: 2.0A resistive at rated voltages

• Minimum load: 100 µA at 100 mV dc

• On‑state voltage drop (max): 0.5V @ 2.0A, 24V dc resistive (key parameter)

• Initial contact resistance: 30 mΩ (key parameter)

• Expected contact life:

  • 300,000 cycles (resistive)

  • 100,000 cycles (inductive)

• Off‑state leakage (max): 1.5 mA

• Output delay time: Off→On ≤10 ms, On→Off ≤10 ms

• Indicators: 6 green LEDs (one per output)

• Common type: 1 point / 1COM (each relay has its own common terminal)

General & Power Specifications

• DeviceNet power supply: 24V dc nom (range 11‑28.8V dc)

• DeviceNet power dissipation: 1.2W max @ 28.8V dc

• Field power supply: 24V dc nom (range 19.2‑28.8V dc)

• Field power dissipation: 10 mA @ 28.8V dc per channel

• Isolation: I/O to logic via photocoupler, 1250V ac rms isolation voltage (key parameter)

• Wiring terminal block: M3.0 screw type, torque 7 lb‑in max (use copper or copper‑clad aluminum conductors)

Mechanical & Environmental Information

This module is designed for industrial control cabinets. It does not require additional heatsinking under rated load. The base module mounts directly on a DIN rail or panel.

Furthermore, the 1790D-T0W6 operates reliably in temperatures from 0°C to 55°C. Storage temperature ranges from -40°C to 85°C. Humidity tolerance is 5‑95% non‑condensing.

Because the off‑state leakage is only 1.5mA, you can use it with very low‑power loads without false triggering. Additionally, the initial contact resistance of 30 mΩ ensures minimal power loss.

Installation Guidelines

First, ensure the DeviceNet network power (24V dc) and field power (19.2‑28.8V dc) are turned off. Next, mount the 1790D-T0W6 on a DIN rail or using panel mounting screws.

For wiring, use copper conductors with a cross‑section of 0.5‑1.5 mm² (20‑16 AWG). Tighten the M3 screws to 7 lb‑in maximum. Each common terminal is isolated from others, so you can mix different voltage groups on the same module.

Finally, connect the DeviceNet cable to the module’s pass‑through connectors. Then apply power and check the green LEDs. Each LED lights when the corresponding output is energized.

Packaging List (Per Unit)

• 1790D-T0W6 6 Relay Output Base Module – 1 pc

• Terminal block (pre‑attached) – 1 pc

• Quick start guide (printed) – 1 pc

• Dust cover – 1 pc

Note: No certificates or warranty documents are included in the package.

Shipping & Delivery

We ship worldwide via FedEx, UPS, or DHL. All modules are packed in anti‑static and anti‑shock materials. Tracking number will be provided within 24 hours after dispatch.

Frequently Asked Questions (FAQ)

1. Can I switch inductive loads with the 1790D-T0W6?
Yes, but you should add an external suppression device (e.g., a diode for DC or an RC snubber for AC). The expected contact life for inductive loads is 100,000 cycles.

2. What happens if I exceed 2.0A per relay?
Exceeding 2.0A resistive may cause contact welding or reduced life. Always stay within the rated 2.0A at 250V ac or 24V dc.

3. Does the 1790D-T0W6 support mixed voltages on different relays?
Absolutely. Each relay has its own common terminal (1 point/1COM). You can wire one relay to 24V dc and another to 120V ac on the same module.

4. Is the module hot‑swappable under DeviceNet?
No, you must disconnect DeviceNet power and field power before removing or inserting the 1790D-T0W6. Otherwise, you may damage the module or the network.

5. How do I know when a relay fails?
Check the green status LED. If the LED is on but the load does not switch, the contact may be worn. Also, measure the contact resistance – values above 30 mΩ indicate aging.