Lectrosonics DM84 Reference Manual page 38

DM84 Digital Matrix Processor
Rear Panel Control Tab
The DM84 has 11 programmable inputs which can be
used to control a wide variety of DM84 functions.
Depending on the assigned function, the inputs may be
connected to momentary contact switches, toggle
switches, or potentiometers. When used with a switch,
the inputs are activated by connecting them to ground
through the switch contacts, called a "contact closure".
When used with a potentiometer, the inputs respond to
the applied voltage in the range 0 to 5 VDC.
The DM84 also has a set of 8 programmable outputs
which can be set up to monitor programmable input
status or whether particular presets are active. Normally,
a programmable output is inactive unless the specified
conditions are fulfilled, at which time it becomes active.
However, a programmable output can be inverted so
that the reverse is true - it becomes active whenever the
specified conditions are not fulfilled. Programmable
outputs act as an electronic "contact closure" to ground.
When the output is active, the contacts are closed
(conducting to ground), when inactive they are open.
An important application of the rear panel control
interface is to manage what is called the rear panel gain
Programmable
Input/Output
Function Select
Programmable
Input/Output
Notebooks
Page Select
Programmable
Input/Output Status
Indicators
Programmable
Inputs/
Programmable
Outputs Select
38
for input and output audio channels. This is an addi-
tional gain value that is added to the "main" gain value
for a channel to give the total gain applied. Rear panel
gain may be adjusted over the range -30dB to 0dB, or
set to "Off" which silences the channel. It is intended to
function as a variable attenuator for the audio channel.
The purpose is to allow some amount of gain or level
control by the end user in a safe manner, using one of
the programmable inputs. A typical application of rear
panel gain is to allow adjustment of the level of an
audio output (driving a speaker) downward from some
maximum by means of turning a potentiometer con-
nected to a programmable input which has been set up
to use the Analog Output RP Gain Control function
(see description in table).
This tab contains a notebook with two pages, one for
programmable input setup and one for programmable
output setup. If the computer is connected to a DM84,
changes made in this tab take effect immediately. As
always, the changes are not permanent unless the
DM84 settings are stored to a preset in nonvolatile
memory.
Rear Panel
Input Gain
Control
Rear Panel
Output Gain
Control
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