Overview
The Allen-Bradley 1746-IA8 is a discrete AC input module engineered for integration into SLC 500 modular control systems. This 8-point input module processes industrial AC signals from sensors, switches, and discrete devices, converting them to digital inputs that the SLC 500 processor can logic. Operating at 85–132V AC (47–63 Hz), the module supports standard North American plant power and delivers fast, reliable switching performance for typical factory automation and machine control applications.
Key Features
- 8 discrete AC inputs grouped as one common, simplifying wiring and reducing chassis real estate
- Wide input voltage range (85–132V AC) provides robust immunity to plant voltage fluctuations
- Fast signal detection: 35 ms on-state delay, 45 ms off-state delay for responsive control
- Status indication with LED feedback per module for real-time troubleshooting
- Modular SLC 500 architecture plugs directly into standard 1746 I/O chassis (4, 7, 10, or 13-slot models)
- North American hazardous-location rated for certain Class/Div industrial environments
Technical Specifications
The 1746-IA8 module consumes minimal backplane current—only 50 mA at 5V DC and 0 mA at 24V DC—and dissipates a total of 2.4 Watts (0.27 W per input point, minimum 0.25 W). Input current is 12 mA at 120V AC with a maximum inrush of 0.8 A over 0.5 ms. Off-state voltage withstand is 30V AC maximum with 2 mA leakage. The module supports up to 10–2000 Hz vibration at 1G, 50G shock when powered off, and 30G when operating, matching industrial environment requirements.
Typical Applications
- Discrete limit switch and proximity sensor inputs for machine tool control
- Start/stop button detection and mode selector feedback
- Compressor or pump run-enable signals on legacy SLC 500 production lines
- Plant-floor equipment integration in facilities with 120V AC power distribution
- Retrofit and expansion of existing SLC 500 control cabinets without processor replacement
Compatibility & Replacements
Compatible With
- SLC 500 modular processors (all versions)
- 1746 I/O chassis in 4, 7, 10, and 13-slot configurations
- Rockwell Automation RSLogix 500 and Studio 5000 ladder logic development platforms
- SLC 500 remote I/O systems via 1747 adapter modules
- Standard DIN rail backplane interconnection (1492 cables)
Replaces / Drop-In Replacement For
- Earlier 1746-IA8 revisions and series
- OEM field-replacement option for damaged or failed input modules in existing cabinets
Works With
- RSLogix 500 offline and online programming environments
- Studio 5000 (Logix Designer) with SLC 500 emulation mode
- IEC 61131-3 ladder, function block, and sequential function chart languages
- Standard EtherNet/IP gateways and remote I/O scanners for distributed control (via separate communications modules)
- PLC Machinery and third-party distributor configuration tools for system design
