1791‑8BC I/O Module | Allen‑Bradley Block I/O – RIO Compatible

1791-8BC – 16-Point Combination Discrete I/O Module

Brand: Allen‑Bradley | Series: 1791 Block I/O | Type: Discrete Input / Output Module

This 16‑channel block I/O module delivers 8 DC inputs and 8 DC outputs in a compact, rackless design. It supports RIO communication and is suited for distributed control architectures. Vertical or horizontal mounting options allow flexible panel placement.

 Oiltech Controls’s Insight

• Proven for legacy PLC‑2, PLC‑5, SLC 500, and Logix platforms via RIO.
• Output current derates with temperature – vertical mounting gives 500 mA @ 60 °C.
• Supports 57.6K, 115.2K, and 230.4K baud; use correct termination resistors.
• Ideal for distributed I/O where space is limited and wiring is centralized.

 Technical Specifications (Compact)

• Inputs: 8 channels, 10‑30V DC, On‑state current 2.5‑11 mA
• Outputs: 8 channels, 10‑30V DC, current rating (vertical) 500mA @ 60°C, 1A @ 30°C
• External power: 19.2‑30V DC, 300 mA max draw
• Communication: Remote I/O (RIO) via 1771‑CD or Belden 9463 cable
• Baud rates: 57.6K, 115.2K, 230.4K (termination: 150 Ω or 82 Ω)
• LED indicators: Per‑channel status + OK LED
• Mounting: DIN‑rail; vertical or horizontal orientation
• Power dissipation: 11.8 W (41 BTU/hr)
• Wiring: 14 AWG stranded max, 3/64″ insulation

 Suitable Equipment & Compatibility

• Allen‑Bradley PLC‑2, PLC‑3, PLC‑5 (1785 series)
• SLC 500 (1747 series), CompactLogix, ControlLogix
• Any RIO‑capable controller using 1771‑CD or Belden 9463 cable
• Works with 1791 series blocks in distributed I/O networks

 Why Buy From Oiltech Controls?

• Over 15 years supplying industrial automation spares.
• Global shipping – FedEx, UPS, DHL available.
• Tested surplus / refurbished inventory for obsolete systems.
• 12‑month warranty on every module.
• Every unit verified with technical checks before dispatch.
• Expert support for legacy control system replacements.

 Shipping & Warranty

• Dispatch: 24‑28 hours after order confirmation.
• Carriers: FedEx, UPS, DHL – tracked worldwide.
• Warranty: 12 months from invoice date.

 5 Professional FAQs

• Q: Can I use this module with ControlLogix without a RIO scanner?
  A: No. You need a RIO communication module (e.g., 1756‑DHRIO) to interface with ControlLogix.
• Q: What happens if I exceed the output current rating?
  A: Internal current protection will activate, but sustained overload may damage the output. Derate according to mounting and temperature.
• Q: Which termination resistor should I choose?
  A: Use 150 Ω for 57.6K and 115.2K baud; use 82 Ω for 230.4K baud. Connect across terminals 6 (BLU) and 8 (CLR).
• Q: Is this module compatible with 24V AC sensors?
  A: No. It accepts only 10‑30V DC inputs. AC signals will not be recognized.
• Q: Can I mix input and output wiring in the same terminal block?
  A: Yes, but group inputs and outputs separately to avoid confusion. Use proper fusing on output circuits.

 Selection Guide (Buying Advice)

• Check your controller’s RIO baud rate – match termination resistor accordingly.
• Calculate total output current per channel; consider derating for horizontal mounting.
• If you need more I/O, consider 1791‑16AC or 1791‑32A0 models.
• For new systems, consider Ethernet/IP alternatives; for legacy upgrades, this module is a direct fit.

Contact:
info@oiltechcontrols.com  |
+86 158 8020 0923 (WhatsApp)

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