Overview
The Allen-Bradley 1771-P4S/B power supply is a compact, single-slot module engineered for the PLC-5 and 1771 product families. This 5VDC power supply delivers up to 8 Amperes of regulated backplane power, making it ideal for systems with moderate to high I/O density. Designed for reliability in industrial control environments, the 1771-P4S/B operates from standard 120VAC industrial distribution and supports parallel-mode operation for extended power capacity.
Key Features
- Regulated 5VDC output: Output voltage of 5VDC and output current of 8 Amperes
- Wide input range: Operates when provided with an input supply range of 92-132VAC along an input frequency range of 47-63 Hz while the module’s nominal input supply voltage is 120VAC
- Parallel support: This module supports operation along another Power supply connected in parallel using the Parallel cable connector
- Field-replaceable fuse: The 1771-P4S comes with a replaceable fuse. The built-in fuse is a 1.5A, 250V Slow-blow which can be replaced by an approved equivalent
- Integrated status indicator: Green P/S ACTIVE LED confirms normal operation
- Terminal block included: This module weighs 1.85 lbs (0.84 kg) and uses the 5-position terminal block with catalog number Allen-Bradley P/N 941274-05, Wago 1 P/N 231-205/000-008. The terminal block is provided with each power supply module
Technical Specifications
- Input voltage (nominal): 120 Volts AC (0.9 Amps)
- Input voltage range: 97 to 132 Volts AC RMS. The input frequency of the module is from 47 to 64 Hertz
- Output voltage: 5 Volts DC while the maximum output current is 8 Amps
- Input power rating: Real input power rating of 59 W and apparent power of 89 VA at a 50 to 60 Hertz line frequency
- Operating temperature: 0 to 60°C (32 to 140 °F), storage temperature of -40 to 85° C (-40 to 185 °F) and relative humidity of 5-95%, non-condensing
- Wire gauge: 14 American Wire Gauge (AWG) single or solid wire only
- Module configuration: Single-slot module that is used to deliver power to the backplane
- Certifications: UL and CSA-certified
- Weight: 1.85 lbs (0.84 kg)
Typical Applications
The 1771-P4S Power Supply Module is a 5V, 8A power supply that can be used in the 1771-A1B, -A2B, -A3B, and -A4B Universal I/O Chassis. Up to two of these supplies may be used as dictated by the power requirements of the 1771 series I/O modules contained in the Universal I/O Chassis. The module is commonly deployed in legacy PLC-5 systems, remote I/O installations, and distributed control networks where regulated DC backplane power is critical to system stability.
Compatibility & Replacements
This module is compatible for use with the 1771-A1B, -A2B, -A3B, and -A4B Universal I/O Chassis. If two power supply modules are used in one Universal I/O Chassis they must be linked together through the Power Supply Paralleling Cable, Allen-Bradley part number 1771-CT. This 1771-P4S/B is a Series B/Revision B module and serves as a direct replacement for earlier -P4S variants. The part is discontinued by the manufacturer but remains widely supported in legacy automation systems. Verify chassis model and required current capacity before installation to ensure proper system performance.
