4020 Power I/O Interface; Application - Simplex 4020 Troubleshooting Manual

4020 Power I/O Interface

Description
Power I/O Interface Functions

Application

The Power I/O Interface circuitry permits the Standard Slave to supervise and
control the Power Supply. A bi-directional 8 bit bus provides Standard Slave
access to Power I/O Interface status and control registers.
The Power I/O Interface assembly converts +28.5 volt A-tap power to 36V
Mapnet power.
Local 28 UPS unswitched power, battery relay control and primary power
supervision is provided by the P9 ribbon cable connection to the Power Supply.
Note: The 28 UPS power is essential for generation of the +5V system
power required for all sub-assembly operation and power supply
supervision and initialization.
The Power I/O Interface assembly provides tap voltage control. Jumper plugs
enable current-limiting Tap Voltages.
Ground fault detection is also performed on this assembly.
The Power I/O Interface:
• Is the interface for power supply supervision & control
• Converts 28.5V DC power to +5V & +36V
• Includes A/D converter for power supply voltage & current supervision
• Monitors Power Supply trouble indications
Two different Power I/O Interfaces exist for specific usage:
1. The 565-256 Power I/O Interface is used with:
• 636-341 Universal Switcher Power Supply (Gold Wing)
• 565-368 Standard Slave PCB
• Software EPROM 741-033 plugged into U11 on Standard Slave
2. The 565-220 Power I/O Interface is used with:
• 636-289 Power Supply (Black Hawk) or 636-370 w/charger adapter
• 565-222 Standard Slave PCB
• Software EPROM 741-008 plugged into U11 on Standard Slave
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