Brand:

• AMX
• BSS Audio

Models:

• AVX Architect

Overview:

In this article, the focus is on expanding basic external control and explaining how to set up a basic fire mute using GPIO.  

To see a video of this article, click HERE.

Description:

In this example, the 5V connection from the GPIO on the back of the processor passes through a normally closed relay and then feeds back into the GPI.

The end goal is for the fire alarm to open the relay, causing the voltage to drop to the GPI and trigger the mute.

The first step is to add a GPI from the DSP into the workspace. 

For this example, the default Logic Binary type and settings are sufficient since the 5 volts from the DSP’s GPIO are being used. 

The other objects represent a basic signal flow of inputs coming in, being processed, and then routed back out to the amplifiers. 

Ideally, the signal should be muted as close to the output as possible.  In this case, a gain object should be added, and its channel count increased so that all channels flow through the gain object. 

For the gain object’s PROPERTIES, it is only necessary to ensure that Master Controls are enabled. This provides the overall SYSTEM mute that is required.

Open the Gain object’s factory panel and enable the selection mode switch. 

Drag the mute from the Master channel into the workspace. 

This creates a logic object tied to the master mute control.  When this object receives a high input, the mute will trigger.  

Since the relay is normally closed, a Logic NOT Gate should be added between the GPI and the logic binary for the mute. 

This is necessary because when the incoming voltage is detected, it provides a high output on the GPI object, which would normally mute the SYSTEM.  There are different ways to accomplish this conversion, and the best method may depend on the components present in the SYSTEM.

Once configured, as long as the voltage is present, the NOT Gate’s output remains in an off state. When the relay opens, the voltage on the meter drops, and the NOT Gate’s output switches to on, muting the gain object. 

For a normally open relay, simply connect the GPI directly to the logic binary object.