Yokogawa PW401 Power Supply Module

The Yokogawa PW401, also cataloged as the PW401 Power Supply Module, operates as a dedicated hardware component for primary backplane DC power conversion within Yokogawa industrial control racks. Configured to step down utility AC lines, the module converts a nominal 100-120 VAC input into a regulated 5.1 VDC output rated at 20 A continuous current (102 W total capacity). It maintains system logic rail stabilization to prevent controller resets during line voltage brownouts or step-load transitions.

Hardware Specifications

4-20 mA HART Loop Protocol and Channel Isolation

The Yokogawa PW401 power supply incorporates galvanic isolation between primary AC supply terminals and secondary DC backplane outputs. This isolation barrier prevents power line transients and ground loops from coupling into internal backplane communication lines or field transmitter interfaces. By suppressing high-frequency switching ripple on the 5.1 VDC logic rail, the module ensures noise-free processing for adjacent analog I/O cards executing 4-20 mA HART loop protocol signal conversions and HART digital overlay demodulation.

Frequently Asked Questions

Q: What is the maximum rated current output for the Yokogawa PW401 5.1 VDC bus rail?

A: The module is engineered to deliver up to 20 A of continuous DC current at a regulated 5.1 VDC output level.

Q: How does the PW401 handle AC input voltage fluctuations?

A: The internal switching power regulator accepts an AC input range from 100 to 120 VAC while maintaining tight 5.1 VDC voltage regulation across full load conditions.

Q: Can the PW401 module be hot-swapped while the system backplane is fully energized?

A: AC supply lines must be isolated at the external circuit breaker prior to inserting or removing the power module to prevent connector arcing.

Field Installation Guidelines

1. Disconnect and isolate primary AC power feeds before installing or removing the PW401 module from the chassis.
2. Align the module top and bottom card guides with the designated power slot in the rack frame.
3. Slide the unit inward until the rear high-current backplane pins seat completely into the receptacle.
4. Tighten the top and bottom front plate screws to 0.8 Nm to secure the module and maintain earth continuity.
5. Terminate AC supply conductors at the screw terminal block, ensuring the protective earth (PE) wire is grounded directly to the cabinet earth bar.