1791-24B8 24V DC I/O Module 10-30V Allen-Bradley

1791-24B8 Allen‑Bradley 24‑Input 8‑Output DC Block I/O Module

Key Technical Specifications

• Manufacturer: Allen‑Bradley.
• Model: 1791-24B8 – 24‑point DC input / 8‑point DC output Block I/O.
• Input voltage range: 10‑30V DC (on‑state), with 11 mA max at 30V. Off‑state voltage below 5V DC ensures noise immunity.
• Input characteristics: 3.4 kΩ impedance, programmable delay: fast (1 ms ON / 5 ms OFF) or slow (1 ms ON / 18 ms OFF).
• Output current rating: 0.5 A to 1 A per channel (derated above 30 °C, depends on mounting orientation).
• Surge capability: 3 A for 50 ms, repeats every 2 s – handles inrush loads like solenoids.
• External power requirement: 19.2‑30V DC, 300 mA – module includes internal protection against reverse polarity.
• Environmental range: 0 °C to 60 °C (32 °F to 140 °F), 5 % to 95 % relative humidity non‑condensing.
• Dimensions & weight: 176.5 x 68.8 x 98 mm (6.95 x 2.7 x 3.85 in), 1.75 lb (0.79 kg).

Frequently Asked Questions (FAQ)

• Can the 1791-24B8 outputs drive inductive loads like relays? Yes, but add a freewheeling diode across the DC coil to protect the output transistor from voltage spikes.
• What is the minimum input current to guarantee ON state? At 11V DC the input draws at least 2.5 mA, which reliably turns on the channel.
• Does horizontal mounting reduce output current? Yes – above 30 °C horizontally mounted units derate from 500 mA to 250 mA; vertical mounting allows up to 1 A below 30 °C.
• How do I select fast or slow input filtering? The 1791-24B8 has no on‑board switch; the selection is made via the programming software of the controlling PLC.
• What is the power dissipation of this module? Maximum 17.1 W (58.1 BTU/h) – ensure adequate ventilation inside the panel.

For inquiries or to place an order, contact us at sales@nex-auto.com or +86 153 9242 9628 (WhatsApp).
Partner: NexAuto Technology Limited