Orban OPTIMOD-FM 5518, Operating Manual

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5518-FM DIGITAL TECHNICAL DATA
6-7
User Control Interface and LCD Display Circuits
The user control interface enables the user to control the 5518’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 5518. 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 5518 has eight remote contact closure inputs.
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 5518 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 5518 control software. The host microprocessor
controls the system setup and function of the DSP according to the switch/rotary
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.