The YASKAWA JRMSP-P8101 (often simply referred to as the P8101) is a high-capacity Main Power Supply Module from the legacy Memocon-SC series
(specifically the U84 and 1000 series architectures).
It is the primary energy source for large-scale PLC racks, providing the necessary DC voltages to power the CPU, memory, and specialized I/O modules.
Introduction
The JRMSP-P8101 is a heavy-duty power supply unit designed to be mounted on the far-left side of a Memocon-SC mounting base (such as the JRMSI-B1031).
It is known for its extreme reliability in high-demand industrial environments, particularly in the marine and heavy manufacturing sectors.
It converts 100V AC input into stabilized DC rails for the internal system bus.
Technical Parameter Table
| Parameter | Specification |
| Model Number | JRMSP-P8101 (Type: P8101) |
| Series | Memocon-SC (U84 / 1000 Series) |
| Input Voltage | 100V AC (Standard) |
| Max Current (Input) | Approx. 10A |
| Output Rails | Stabilized DC for Logic and Field Bus |
| Cooling | Natural Convection / Integrated Heat Sink |
| Mounting | Dedicated Power Slot on Memocon-SC Rack |
| Weight | Approx. 5.27 kg to 11.5 kg (depending on housing/revision) |
| Regulatory | Industrial Standards (Standard Japanese MFG) |
Product Advantages and Features
High Current Output: Specifically designed to support fully loaded 10-slot or 12-slot racks without voltage drops.
Marine-Grade Durability: Frequently found in maritime applications due to its high resistance to humidity and vibration.
JRMSP-P8101
Integrated Protection: Features robust over-voltage and over-current protection to shield sensitive CPU modules (like the U84-124) from power spikes.
Diagnostic Indicators: Includes “Power” and “Error” LEDs to help maintenance personnel verify incoming AC and internal DC health at a glance.
Stable Field Power: Often provides a dedicated output for field-side sensors, ensuring a clean 24V source.

JRMSP-P8101
Application Cases
Shipboard Automation: Powering control systems for engine room monitoring, ballast control, and winch systems.
Steel & Iron Works: Managing the logic for high-heat production lines where power stability is critical to safety.
Legacy Factory Racks: Serving as the central power hub for Yaskawa U84 series controllers in automotive and textile plants.
Large-Scale Conveyor Systems: Providing the power for complex distributed I/O networks in older distribution centers.
Other Models in the Same Series
The JRMSP series includes various power supplies tailored for different input voltages and rack sizes:
| Model | Function / Description |
| JRMSP-P8100 | Standard Power Supply (lower capacity/earlier revision). |
| JRMSP-P8102 | 200V AC Input version of the P8101. |
| JAMSC-P1010 | Compact Power Supply for smaller 1000-series racks. |
| JRMSI-B1030 | 5-Slot Mounting Base (Commonly powered by the P8101). |
| DDSCR-U84-124 | The CPU board often paired with this power supply. |
Troubleshooting a System Failure?
If your Memocon-SC rack is completely dead or the CPU is showing a “Watchdog” or “Bus Error,” the JRMSP-P8101 is the first part to check.
These legacy units often require “recapping” (replacing old electrolytic capacitors) to restore full power stability.


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