User Control Interface And Lcd Display Circuits - Orban OPTIMOD-FM 5500 Operation Manual

OPTIMOD-FM DIGITAL
The control board contains interface circuitry, the CPU, the Ethernet interface chip,
the flash memory, the DRAM, the RS-232 serial interface circuitry, the GPI/O interface
circuitry, and the real-time clock, which keeps time for the 5500's automation func-
tions. The real-time clock is backed up by a DL2032 battery so that it keeps accurate
time even when the 5500 is powered down. The battery is socketed and can be
readily accessed by removing the 5500's top cover; the battery is located on the con-
trol board.

User Control Interface and LCD Display Circuits

The user control interface enables the user to control the 5500's functionality. A rear
panel GPI connector allows optically-isolated remote control of certain functions,
such as recalling presets, via contact closure. An RS-232 serial port and an Ethernet
port allow you to connect a modem or computer to the 5500. Front panel pushbut-
ton switches select between various operational modes and functions. A rotary en-
coder allows the user to adjust parameters and enter data.
1. Remote Interface and RS-232 Interfaces
Located on control board
A remote interface connector and circuitry implements remote control of certain
operating modes; Model 5500 OPTIMOD-FM has eight remote contact closure in-
puts.
A valid remote signal is a momentary pulse of current flowing through remote
signal pins. Current must flow consistently for 50msec for the signal to be inter-
preted as valid. Generally, the 5500 will respond to the most recent control op-
eration, regardless of whether it came from the front panel, remote interface, or
RS-232.
Component-Level Description:
After being current limited by resistors, the GPI control signals are applied to
two quad optoisolators, U17, U19, and then to the control circuitry.
Transceiver U12 interfaces the RS-232 signal levels at SERIAL DB-9 connector J5
to/from the TTL levels of the corresponding pins of the SC520 microcontroller.
U12, U17, and U19 are 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 5500 control software. The host microprocessor
controls the system setup and function of the DSP according to the switch/rotary
6-7
TECHNICAL DATA