Setting up Rear Panel controls

Select the Rear Panel Ctrl Tab. The DM84 has 11 programmable inputs which can be used to control a wide variety of DM84 functions. Depending on the function assigned to them, these inputs may be connected to momentary contact switches, toggle switches, or potentiometers. When used with a switch, the inputs are activated by 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.

Another feature of the rear panel control interface are a set of 8 programmable outputs which can be set up to monitor audio input channel activity, programmable input status, or whether or not 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 - becoming active whenever the specified conditions are not fulfilled, and vice versa. 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 for input and output audio channels. This is an additional 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 -60dB to 0dB, or set to "Off" to silence 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 connected to a programmable input which has been set up to use the Analog Output RP Gain Control function described below.

This tab contains a notebook with two pages, one for programmable input setup and one for programmable output setup. If 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.

The rear panel control settings (ALL of them, as a group) can be copied and pasted into another preset.

The first tab along the bottom of the rear panel control notebook is used to select the programmable inputs page. On this page the following controls and indicators are always visible:

Here is a view of the Rear Panel Ctrl Tab with the programmable inputs page selected:

The second tab along the bottom of the rear panel control notebook is used to select the programmable outputs page. On this page the following controls and indicators are always visible:

Here is a view of the Rear Panel Ctrl Tab with the programmable outputs page selected:

Programmable inputs notebook

Settings for the 11 programmable inputs are contained within a notebook, with one page per programmable input. The tabs along the bottom of the notebook are used to select one of the programmable inputs for setup.

To set up one of the programmable inputs, select a function type from the Function list. Once selected, controls appear which are used to choose the specific feature or features of the DM84 that the function applies to. These choices will vary according to the nature of the programmable input function values. The following function types are available:

When certain functions have been selected and the control panel is connected to a DM84, the Test button is enabled. Pressing this button simulates a contact closure on the programmable input and is very useful for testing the function.

Programmable input status indicators

These display the status of the corresponding programmable input when a function has been assigned and the control panel is connected to a DM84. For the Analog Gain Control functions, the indicator is lit red when the voltage applied to the input is in the upper half of the allowable 0 to 5VDC range. For all other functions, the indicator is lit red when a contact closure occurs.

Rear panel input gain controls

These are used to set up rear panel gain control for input channels. This operates as an attenuator, adjustable from some minimum gain (max attenuation) up to 0dB (no attenuation). There are two parameters:

The group consists of these numerical controls and indicators:

Rear panel output gain controls

These are used to set the range over which the rear panel gain of an output channel can be adjusted by certain programmable input functions. These function in the same manner as the Rear panel input gain controls described above.

Programmable outputs notebook

Settings for the 8 programmable outputs are contained within a notebook, with one page per programmable output. The tabs along the bottom of the notebook are used to select one of the programmable outputs for setup.

To set up one of the programmable outputs, select a function type from the Function list. Once selected, controls appear which are used to choose the specific feature or features of the DM84 that the function applies to. These choices will vary according to the nature of the programmable output function values. The following function types are available:

To finish the setup, the programmable output invert status may be set using the Invert checkbox. If inverted, a programmable output will behave in a manner opposite to that described above in the function descriptions.

Programmable output status indicators

These are lit red when the corresponding programmable output becomes active (conducting to ground).

Channel activity controls

When the Monitor Input Ch Activity function is assigned to a programmable output, these are used to set the parameters controlling the time response of the function:

The group consists of two numerical controls:

Rear Panel Ctrl Copy/Paste

The entire group of rear panel control settings can be copied and pasted into another preset. This can save a lot of time when a common rear panel setup needs to be duplicated in multiple presets. There are two ways to do this:

Copyright © 2006 Lectrosonics, Inc.