4-54
888-2586-001
9/15/06
WARNING: Disconnect primary power prior to servicing.
Platinum Z16HD+
Section 4 Overall System Theory
•
All power supply monitoring and fault detection. These include voltage, current, tem-
perature and status.
4.8.6.1
Power Supply Turn On
The primary function of the PS Controller is to turn the power supplies on and off. The
on/off signal is called PS_DISABLE and comes in on J3-13. The signal originates on
the Master Controller but passes through a logic gate on the Life Support Board before
reaching the PS Controller. PS_DISABLE is an active high signal which means that if
the signal is high the power supplies will be shut off (the secondaries will be
deactivated by shutting of the SCRs but primary voltage could still be present). If it is
low, the power supplies will be activated, unless there is a critical fault on the PS
Controller board, in which case the supplies will be shut off regardless of the
PS_DISABLE signal. The power supplies are turned on via one of the four outputs:
•
DRIVER 1 (TAP 1 = 48Vdc)
•
DRIVER 2 (TAP 2 = 50Vdc)
•
DRIVER 3 (TAP 3 = 52Vdc)
•
DRIVER 4 (TAP 4 = 54Vdc)
These outputs are duplicated, one set for PS1 and the other for PS2. When the
transmitter is turned on the Master Controller brings the PS_DISABLE signal low
(provided the contactor has been activated and the Master Controller is operating
normally). This will first activate the SOFT_START outputs at J1-8 and J2-8. This
allows the supplies to charge slowly, limiting the in-rush current via the soft-start
resistor and SCRs on the rectifier boards. The supply voltage must reach at least 40Vdc
within 3-5 seconds, otherwise the turn on sequence will be aborted. After 3-5 seconds,
if the voltage is within tolerance, the PS Controller will activate the lowest available
voltage tap by activating one of the four DRIVER signals. Since DRIVER_1 is
connected to the 48V tap, it will be activated first (if available) and the power supplies
will come up to full charge.
The PS Controller will now check the power supply voltages via the DC Voltage
Samples from each power supply. These come into the board at J1 and J2, pins 13 and
14 from the rectifier boards. These signals pass through U7 which acts as a linear
amplifier and buffer to prevent the analog samples from overloading the front end of the
A/D converter in the microcontroller IC, U6. Using these samples the PS Controllers
will determine when and if it is necessary to change taps to increase or decrease the DC
PA voltage. It will try to maintain the voltage as close as possible to 52Vdc.
Summary of Contents for Platinum Z16HD+
Page 4: ...MRH 2 888 2586 001 9 15 06 WARNING Disconnect primary power prior to servicing ...
Page 6: ...9 15 06 888 2586 001 MRH 1 WARNING Disconnect primary power prior to servicing ...
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