Allen‑Bradley 1791‑16BC Block I/O – 16 Input 16 Output Module

1791-16BC – Allen‑Bradley 16 Input / 16 Output Block I/O Module

Compact remote I/O block with embedded power and communication. Provides 16 digital inputs and 16 digital outputs in a single chassis. Ideal for distributed control architectures.

• Inputs: 16 channels, 10‑30V dc, sinking/sourcing
• Outputs: 16 channels, 10‑30V dc, 0.5 A per point
• Interface: Remote I/O (RIO) adapter – supports PLC‑2, ‑3, ‑5, SLC 500
• Baud rates: 57.6K, 115.2K, 230.4K (cable length up to 10,000 ft)

Technical Specifications – 1791‑16BC

• Manufacturer: Allen‑Bradley
• Series: 1791 Block I/O
• Part number: 1791‑16BC
• Weight: 2.25 lbs (1.02 kg)
• Dimensions: 6.95H x 4.35W x 3.85D inches
• Input on‑state: 10‑30V dc, 11 mA @ 30V max
• Input off‑state: 5V dc max, 1.5 mA min
• Output voltage range: 10‑30V dc
• External power: 19.2‑30V dc, 300 mA
• Power dissipation: 17.8 W max; thermal 60.6 BTU/hr
• Mounting: vertical or horizontal (derating applies)
• Internal fusing: inputs fused; outputs not fused

Mounting & Environmental Guidelines

• Mount vertically or horizontally – derate output current at higher temps.
• Vertical (60 °C): 0.5 A; Horizontal (60 °C): 0.25 A.
• At 30 °C: vertical 1.0 A, horizontal 0.5 A.
• Surge current: 3 A for 50 ms.
• Requires enclosure (IP rating per site classification).
• Clearance: 2 inches on all sides for airflow.

Compatibility & System Integration

• Works with PLC‑2, PLC‑3, PLC‑5, SLC 500 families.
• Remote I/O adapter mode – requires a RIO scanner.
• Daisy‑chain topology; max 10,000 ft at 57.6K baud.
• Baud rate selection: 57.6K, 115.2K, or 230.4K.
• Ideal for distributed I/O in large plants.

Oiltech Controls’ Insight – Expert Selection Guide

• Best for: Upgrading legacy RIO networks without changing controllers.
• Use with: PLC‑5 or SLC 500 systems – plug‑and‑play replacement.
• Avoid: High‑speed counting or PWM outputs – use dedicated modules.
• Tip: Always verify baud rate and cable length before installation.
• Legacy support: Direct drop‑in for 1791‑16BC series.

5 Professional FAQs – with buying advice

• Q: Can I mix input and output voltages?
  A: Yes, inputs and outputs both accept 10‑30V dc independently. No polarity restriction.
• Q: What cable length works best at 230.4K baud?
  A: Max 2,500 ft. For longer runs, reduce baud rate to 57.6K (10,000 ft).
• Q: Do I need external fusing for outputs?
  A: Outputs are not fused – we recommend external fast‑acting fuses (0.5 A per point).
• Q: Can I mount this module outdoors?
  A: No, it requires an IP65+ enclosure. Use indoors in a clean, dry panel.
• Q: Is this a direct replacement for 1791‑16BC?
  A: Yes, identical footprint and wiring. Check firmware rev for PLC‑2 compatibility.

Why Buy From Oiltech Controls?

• 15+ years in industrial automation spares – we know legacy.
• Global shipping via FedEx, UPS, DHL – 24‑28 hour dispatch.
• Tested surplus & refurbished – fully verified before shipment.
• 12‑month warranty on every module – peace of mind.
• Technical verification – we check parameters per your application.
• Support obsolete systems – we stock hard‑to‑find parts.

Contact Information
Email: info@oiltechcontrols.com
WhatsApp: +86 158 8020 0923

Copyright © 2026 Oiltech Controls Limited. https://www.oiltechcontrols.com/ All rights reserved.