1771-IH DC Input Module – 8-Channel Digital PLC-5
The 1771-IH is a digital DC input module for Allen‑Bradley PLC‑5 and Bulletin 1771 systems. It provides 8 sink/source inputs with a wide 10‑60V DC operating range. Designed for rack mounting, it includes a 1771‑WA wiring arm for simple installation and maintenance. The module delivers reliable signal detection with red status LEDs for each channel, making it a practical choice for legacy and new control architectures.
Technical Specifications
- Part Number: 1771‑IH
- Brand: Allen‑Bradley / Rockwell Automation
- Inputs: 8 digital DC channels (sink/source)
- Voltage Range: 10‑60V DC (24‑50V nominal)
- Backplane Current: 74 mA @ 5V DC ±5%
- Signal Delay (On): 15 ms ±7 ms
- Signal Delay (Off): 20 ms ±9 ms
- Isolation: 1500V AC RMS
- Power Dissipation: 0.4 W (min) to 8.1 W (max)
- Thermal Dissipation: 1.3 to 27.7 BTU/hr
- Operating Temp: 0‑60 °C (32‑140 °F)
- Wiring Arm: 1771‑WA (included)
Installation & Maintenance
- Rack mountable – fits one slot in a 1771 chassis.
- 1771‑WA wiring arm allows module swap without rewiring.
- Red status indicators per channel for fast visual diagnostics.
- Operates in clean, dry industrial environments (0‑60 °C).
- Compatible with standard PLC‑5 backplanes and power supplies.
Compatibility & Best‑Use Scenarios
- Works with: PLC‑5 processors, 1771 I/O racks, and legacy control systems.
- Ideal for: DC input sensing in conveyor systems, packaging lines, and material handling.
- Supports both sinking and sourcing field devices (24‑48V DC).
- Replaces older 1771‑Ix series modules with similar footprint.
Oiltech Controls’s Insight
- ✓ The 1771‑IH is a workhorse for digital DC inputs. Its wide voltage tolerance (10‑60V) handles noisy industrial lines well.
- ✓ We recommend verifying the off‑state current (<1 mA) to avoid false triggers with high‑impedance sensors.
- ✓ For retrofit projects, the 1771‑WA arm saves hours of re‑wiring – a small detail that pays off.
- ✓ This module is obsolete‑friendly; we test every unit before shipment to ensure reliable performance in legacy systems.
Why Buy From Oiltech Controls?
- ▸ 15+ years in industrial automation spares – we know legacy gear.
- ▸ Global shipping via FedEx, UPS, or DHL (24‑28 hour dispatch).
- ▸ Every unit is pre‑tested (surplus or refurbished) for full functionality.
- ▸ 12‑month warranty – we stand behind our modules.
- ▸ Technical verification before shipment – no surprises.
- ▸ Dedicated support for obsolete control systems – we keep old plants running.
Frequently Asked Questions (Expert Picks)
- Q: Can the 1771‑IH handle 48V DC sensors directly?
A: Yes. Its nominal range is 24‑50V DC, and it accepts up to 60V DC maximum. We suggest using a 48V supply for stable operation. - Q: What is the typical off‑state current, and why does it matter?
A: Off‑state current is ≤0.7 mA (max 1 mA). This prevents leakage from turning on the input – critical when using proximity sensors with residual current. - Q: How do I choose between 1771‑IH and 1771‑IBN?
A: Use 1771‑IH for wide‑range DC (10‑60V) and sink/source flexibility. Choose 1771‑IBN for dedicated 24V DC with higher density (16 points) if voltage range is narrow. - Q: What happens if the backplane current exceeds 74 mA?
A: The module draws 74 mA max. If your backplane is heavily loaded, we recommend calculating total current (all modules) to stay within the power supply rating – typically 8‑16 A for 1771 racks. - Q: Is the 1771‑WA wiring arm compatible with other modules?
A: Yes, it fits many 1771 I/O modules, so you can standardise wiring arms across your rack for faster maintenance.
Contact our technical team: info@oiltechcontrols.com | WhatsApp +86 158 8020 0923
Copyright © 2026 Oiltech Controls Limited. https://www.oiltechcontrols.com/ All rights reserved.
Reviews
There are no reviews yet.