Allen-Bradley 1771-A4B PLC-5 Universal I/O Chassis
The Allen-Bradley 1771-A4B, also cataloged as the 1771-A4B PLC Chassis, operates as a dedicated hardware component for physical module housing and backplane power distribution within Allen-Bradley PLC-5 systems. It provides structural mounting and high-speed internal bus connectivity across 16 module slots to facilitate signal exchange between processors and I/O modules.
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 1771-A4B |
| Brand | Allen-Bradley |
| Origin | USA |
| Weight | 13.36 lbs (6.06 kg) |
| Dimensions | Standard 16-slot Allen-Bradley 1771 Chassis Form Factor |
| Operating Temp | 0 to 60 deg C |
| Power Consumption | Passive chassis backplane (supplies up to 24 A at 5.25 VDC) |
| Slot Capacity | 16 Slots |
| Maximum Current Rating | 24 A backplane capacity |
| Voltage Rating | 5.25 VDC backplane bus |
| Subsystem Type | Universal I/O Chassis |
Backplane Bus Communication Velocity & I/O Density Scaling
The 1771-A4B Universal I/O Chassis enables high backplane bus communication velocity and supports maximum I/O density scaling across complex industrial control architectures. Its integrated multi-slot backplane traces maintain low-impedance power distribution up to 24 A at 5.25 VDC while insulating high-speed parallel data lines against internal cross-talk. Dedicated slot keying prevents hardware damage by ensuring only compatible PLC-5 processor, communication, and 1771 I/O modules can seat into assigned positions.
Frequently Asked Questions
Q: What power limits govern module selection in the 1771-A4B chassis?
A: The total current draw of all installed modules must not exceed the chassis maximum backplane current rating of 24 A at 5.25 VDC, as supplied by the external power supply unit.
Q: Can the 1771-A4B chassis accommodate both 1-slot and 2-slot addressing modes?
A: Yes, the chassis backplane supports 2-slot, 1-slot, and 1/2-slot I/O addressing modes configured via backplane DIP switch settings on the chassis frame.
Field Installation Guidelines
- Physical Mounting: Mount the 1771-A4B chassis securely in an industrial enclosure using standard mounting screws. Ensure adequate vertical clearance for convection airflow across all 16 slots.
- Backplane Power Connection: Connect the designated external power supply module to the chassis power harness, ensuring proper polarity and secure terminal tightening to support 5.25 VDC distribution.
- Grounding Protocols: Wire a heavy-gauge copper grounding strap from the ground stud on the chassis frame directly to the main enclosure earth ground bar to eliminate electrostatic discharge risks.
Allen-Bradley 1771-A4B PLC-5 Universal I/O Chassis
Allen-Bradley 1771-A4B PLC-5 Universal I/O Chassis
The Allen-Bradley 1771-A4B, also cataloged as the 1771-A4B PLC Chassis, operates as a dedicated hardware component for physical module housing and backplane power distribution within Allen-Bradley PLC-5 systems. It provides structural mounting and high-speed internal bus connectivity across 16 module slots to facilitate signal exchange between processors and I/O modules.
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 1771-A4B |
| Brand | Allen-Bradley |
| Origin | USA |
| Weight | 13.36 lbs (6.06 kg) |
| Dimensions | Standard 16-slot Allen-Bradley 1771 Chassis Form Factor |
| Operating Temp | 0 to 60 deg C |
| Power Consumption | Passive chassis backplane (supplies up to 24 A at 5.25 VDC) |
| Slot Capacity | 16 Slots |
| Maximum Current Rating | 24 A backplane capacity |
| Voltage Rating | 5.25 VDC backplane bus |
| Subsystem Type | Universal I/O Chassis |
Backplane Bus Communication Velocity & I/O Density Scaling
The 1771-A4B Universal I/O Chassis enables high backplane bus communication velocity and supports maximum I/O density scaling across complex industrial control architectures. Its integrated multi-slot backplane traces maintain low-impedance power distribution up to 24 A at 5.25 VDC while insulating high-speed parallel data lines against internal cross-talk. Dedicated slot keying prevents hardware damage by ensuring only compatible PLC-5 processor, communication, and 1771 I/O modules can seat into assigned positions.
Frequently Asked Questions
Q: What power limits govern module selection in the 1771-A4B chassis?
A: The total current draw of all installed modules must not exceed the chassis maximum backplane current rating of 24 A at 5.25 VDC, as supplied by the external power supply unit.
Q: Can the 1771-A4B chassis accommodate both 1-slot and 2-slot addressing modes?
A: Yes, the chassis backplane supports 2-slot, 1-slot, and 1/2-slot I/O addressing modes configured via backplane DIP switch settings on the chassis frame.
Field Installation Guidelines
- Physical Mounting: Mount the 1771-A4B chassis securely in an industrial enclosure using standard mounting screws. Ensure adequate vertical clearance for convection airflow across all 16 slots.
- Backplane Power Connection: Connect the designated external power supply module to the chassis power harness, ensuring proper polarity and secure terminal tightening to support 5.25 VDC distribution.
- Grounding Protocols: Wire a heavy-gauge copper grounding strap from the ground stud on the chassis frame directly to the main enclosure earth ground bar to eliminate electrostatic discharge risks.
