Configured for multi-slot I/O module power delivery and backplane signal communication across Allen-Bradley PLC-5 system architectures, the Allen-Bradley 1771-A1B (1771-A1B Chassis Assembly) provides direct physical/electrical execution.
Hardware Specifications
Parameter
Specification
Model
1771-A1B
Brand
Allen-Bradley
Origin
USA
Weight
7.69 lbs (3.49 kg)
Dimensions
Standard 5-Slot 1771 Chassis
Operating Temp
0 to 60 deg C (32 to 140 deg F)
Power Consumption
16 A at 5.25 VDC Backplane Rating
Slot Capacity
5 I/O Slots
Enclosure Style
Open Frame Chassis Assembly
System Compatibility
Allen-Bradley 1771 I/O Modules & PLC-5 Processors
Backplane Bus Communication Velocity & I/O Density Scaling
The Allen-Bradley 1771-A1B chassis assembly functions as a 5-slot physical enclosure and electrical backplane for housing 1771 digital, analog, and intelligent I/O modules. Designed to maintain high signal transmission velocity across backplane bus traces, the frame distributes 5.25 VDC logic power up to 16 A from an external system power supply module. Heavy-gauge metal housing ensures structural rigidity and grounding protection against electromagnetic interference, supporting high I/O density scaling in modular industrial control racks.
Frequently Asked Questions
Q: What is the maximum backplane current rating supported by the 1771-A1B 5-slot chassis?
A: The 1771-A1B backplane bus is rated to supply up to 16 A of total current at 5.25 VDC to installed 1771 I/O modules and local adapters.
Q: Can PLC-5 processors and 1771 modules be installed directly into the 1771-A1B chassis?
A: Yes. The 1771-A1B accepts standard single-slot or double-slot PLC-5 controllers, power supplies, and 1771 I/O cards using card guides and swing-arm field terminal connections.
Q: How is chassis grounding established for the 1771-A1B assembly during field installation?
A: Grounding is established via dedicated chassis grounding studs on the frame assembly, which must be connected to the central control panel ground bus bar with heavy-gauge grounding wire.
Field Installation Guidelines
Mount the 1771-A1B chassis assembly securely onto the enclosure backpanel using standard mounting hardware.
Connect a low-impedance ground wire from the chassis ground terminal to the main system ground bus bar.
Ensure the backplane power supply module or cable connector is seated properly into the dedicated rack connector.
Insert I/O modules along the plastic card guides until rear edge connectors latch completely with the backplane sockets.
Secure all module retaining screws and swing-arm field wiring assemblies before energizing power to the rack.
