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CT 9000 ® ADV
+12V Supply
The +12V supply is supplied to the MOTHERBOARD, the CPU
board and is used as the bulk supply for the POWERHEAD
board.
The +12V regulator is identical to the +5V regulator with the excep-
tion of the divider circuit which sets the output voltage. The output
voltage for the +12V supply is calculated as follows:
Vout
= 2.21V (1 + R3/R2)
= 2.21V(1 + 9760/2210)
= 11.97V
Powerhead Interface
The powerhead interface provides the interface between the
powerhead DB-25 connector and the CPU board. The pin out for
the powerhead DB-25 connector is given in Table 3-1.
RS-422 transmitter U4 pin 9 translates serial communications
(TXDB) from the CPU board for transmission to the POWERHEAD.
RS-422 receiver U13 pin 11 translates the RS-422 serial communi-
cations (RXDB) and motor encoder quadrature pulses transmitted
from the POWERHEAD
board to the CPU board. The motor en-
coder quadrature pulses are input to J-K flip flop U14 pin 3 and 4 to
generate a motor direction signal to the CPU board. A high on U14
pin 6 indicates the motor is expelling. A low on U14 pin 6 indicates
that the motor is filling.
The serial communications between the POWERHEAD and CPU
boards are combined by U6 pin 6 and converted to RS-422 by U4
pin 15. The resulting signal is output to connector J13 and may be
used to monitor powerhead communications.
800961-C
Nov. 2000
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