Orban OPTIMOD 6300 Operating Manual page 267

OPTIMOD 6300 DIGITAL
Component-Level Description:
After being current limited by resistors, the GPI control signals are applied to
two quad optoisolators, U17, 19, and then to the control circuitry.
U12 is the RS323 port interface chip. It is socketed for easy field replacement in
the event of overload, lightning damage, etc. All other circuitry is surface-
mount and is not field-repairable.
2. Switch Matrix and LED Indicators
Located on display board
Eleven front panel pushbutton switches are arranged in a matrix, configured as
three columns and four rows. These switches are the primary element of the
physical user interface to the 6300 control software. The host microprocessor
controls the system setup and function of the DSP according to the switch / ro-
tary encoder entered commands, the AES status bits from the digital input signal,
the RS-232, and the remote control interface status. The microprocessor updates
the LED control status indicators accordingly.
Component-Level Description:
S1-S11 are the front panel pushbutton switches. CR11-CR15 are the front panel
LED control status indicators. The control microprocessor communicates with
these components through the General Purpose bus, which is buffered via IC3.
3. LED Meter Circuits
Located on display board
The meter LEDs are arranged in an 8x16 matrix, in rows and columns.
Each row of LEDs in the matrix has a 1/8 duty cycle ON time. The rows are multi-
plexed at a fast rate so that the meters appear continuously illuminated. Via the
General Purpose bus, the DSP sends meter data values to the control microproc-
essor, which sends the appropriate LED control words (eight bits at a time) to the
data latches that drive the LEDs directly.
Component-Level Description:
The meter LED matrix consists of ten 10-segment LED bar graph assemblies
(CR1-CR9, CR16) and one discrete LED (CR10). Row selector latches IC4, IC5,
IC6, and IC9 are controlled by the host microprocessor and alternately sink cur-
rent through the LEDs selected by column selector latches IC1 and IC2, which
are also controlled by the SC520. IC1 and IC2 drive the selected row of LEDs
through current limiting resistor packs RP1 and RP2.
6-7
TECHNICAL DATA