Overview
The Allen-Bradley 1746-IB8 Series A is a digital DC input module designed for the SLC 500 programmable logic controller platform. The module features 8 sinking input channels rated at 24 Volts DC and accepts a voltage range of 10-30 Volts DC. This SLC 500 series I/O module is approved for use in all non-hazardous industrial locations and in hazardous industrial locations that have Class 1, Division 2, Groups A, B, C, or D classifications. It is a discontinued-by-manufacturer (DBM) component commonly found in legacy automation systems requiring replacement or expansion.
Key Features
- 8 DC Sinking Input Channels: 8 sinking input channels rated at 24 Volts DC
- Wide Input Voltage Range: 10-30 Volts DC sink configuration
- Fast Response Time: Maximum signal delay of approximately 8ms for both ON and OFF modes
- Compact Design: No-door form factor for straightforward rack mounting and installation
- Industrial Certifications: UL and CE-certified with NEMA standard ICS 2-230 tested Noise Immunity
- Robust Isolation: 1500V AC dielectric withstand and 1500V AC isolation between backplane and inputs
Technical Specifications
- Input Type: DC Sinking (current-sinking)
- Input Voltage Range: 10-30V DC
- Nominal Input Voltage: 24V DC
- Number of Inputs: 8 channels
- Nominal Input Current: 8 milliamps at 24V DC
- Maximum OFF-State Current: 1mA
- Maximum OFF-State Voltage: 5.0V DC
- Response Time: 8ms ON, 8ms OFF
- Power Dissipation: Up to 1.9 Watts during normal operation
- Thermal Dissipation: 1.3W total with 4.4 BTU per hour
- Backplane Current (5V DC): 50 milliamps
- Dielectric Withstand: 1500V AC
- Operating Temperature: 0 to 60°C (32 to 140°F) at 5–95% non-condensing humidity
- Vibration Rating: 2.5G at 57–500Hz
- Shock Rating: 30G
- Weight: 0.35 lbs
- Certifications: UL, CE
Typical Applications
The 1746-IB8 is suited for legacy SLC 500 systems performing:
- Machine automation and material handling signal acquisition
- Facility HVAC and pneumatic pressure monitoring
- Assembly line conveyors and part sorting logic
- Water/wastewater treatment process monitoring
- Industrial process control and interlocking
- General-purpose digital input conditioning in non-hazardous and Class 1, Division 2 environments
Compatibility & Replacements
Compatible With
- SLC 500 processor units (1747-L511, 1747-L521, 1747-L531, 1747-L541, 1747-L551, and other SLC 500 CPU modules)
- SLC 500 I/O rack chassis (1746-A4, 1746-A7, 1746-A10, 1746-A13)
- Classic SLC 500 automation architectures without ControlNet or EtherNet/IP
- RSLogix 500 programming software
Replaces / Drop-In Replacement For
- Allen-Bradley 1746-IB8 (all series: A, B, C, D)
- OEM-equivalent 8-point DC input modules for SLC 500 racks
- Note: Does NOT replace the newer 1734-IB8 (CompactLogix/POINT I/O architecture)
Works With
- Programming Software: RSLogix 500, Studio 5000 (legacy SLC 500 modules only)
- Wiring: Screw-terminal connections; color-coded removable terminal blocks available
- Communication: Local rack-based I/O, no network communication via this module
- Protocol: Series architecture compatible only with native SLC 500 backplane; not compatible with ControlNet or EtherNet/IP
