Video Transcript
Introduction to Q-SYS Control (Part 3)
10m 45s
00:07
Alright, welcome back! Let's go over some GPIO, shall we?
00:11
As you can see, each Q-SYS Core and peripheral has some sort of GPIO support.
00:16
If you look at some of our legacy or integrated cores, you’ll find the DA15 connector on the back.
00:23
Make sure to check the GPIO number versus the connector pin number,
00:27
because they don’t directly correspond.
00:30
Our IO frame has the same DA15 as the 510i located here.
00:35
If you look in Q-SYS Designer, in the Control Properties for a device,
00:39
you have a list of pin assignments and their corresponding functionality.
00:43
Here we have GPIO-1 on pin #3 configured as a digital input.
00:48
This signal would enter your schematic on the right side of the GPIO component.
00:52
We also have this connection configured as an output.
00:56
This signal would feed from the left side of the GPIO component.
01:00
These signals follow the convention for audio inputs and outputs,
01:04
so it should not take long to understand how these lay out in your schematic.
01:08
Also shown here are all the various pins and signal types available on the DA15 connector.
01:13
The layout may look a little strange on the chart,
01:16
but the first three pins physically grouped together on the connector are the relay pins.
01:22
Also, you’ll notice that GPIO 1 is on pin 3, GPIO 2 is on pin 11, and so on.
01:29
Make sure you pay attention to the properties and settings.
01:32
To make these connections easier, we recommend a DA15 breakout block,
01:37
which definitely makes this simpler and creates more flexibility
01:40
than trying to use a crimper and pins on a D-Sub connector.
01:43
So to understanding GPIO concepts, you first must understand the current/voltage relationship.
01:49
First, decide which device is providing the voltage.
01:53
Then, decide which device is going to sync current.
01:56
For instance, if you have a voltage signal and need to light an LED,
02:01
what device is going to sync the current and make the LED illuminate?
02:05
For a better understanding, let’s look at the input anatomy of your typical GPIO input circuity.
02:11
For this example, we have this input configured as a contact closure input and the receiving dry contact
02:18
will not have a voltage on it, so the question is “How do we know when it's closed?”
02:24
The answer is we need some sort of voltage to pull down so that I can read it on the voltmeter,
02:30
which is the intent of a general purpose input circuitry.
02:34
So this example shows a pull-up resistor that will need to be enabled to provide a voltage.
02:40
Now we can measure the voltage until we receive the contact closure,
02:45
the dry contact pulls the voltage low and then the voltmeter in Q-SYS knows the dry contact is closed.
02:52
The different possibilities for input configurations include a digital input TTL 3.3 volt,
02:59
potentiometer, analog input, and a contact closure input.
03:04
Some QSC legacy control panels may also include rotary encoders that have different capabilities.
03:09
So now let’s look at the output side of GPIO.
03:12
The anatomy of this circuit, contains a transistor and some protection circuitry.
03:18
If we toggle the control bit entering the circuit to be low, the transistor provides
03:23
a sync to ground which will provide a logic low on the output.
03:28
If the control bit is driven high, the pull-up voltage will be present on the output.
03:33
This will allow the voltmeter on the connected external device to measure a logic high voltage.
03:40
GPIO output configurations that are available include, digital outputs of 3.3V TTL,
03:47
open collector high current up to 12V DC, and then the Pulse Width Modulated or the PWM pulse train outputs.
03:56
And then finally, there is one dry relay per DA-15 connector.
04:01
Because The Core 110f does not have a DA-15 connector,
04:05
you will need to provide an external relay on a different device and then use the Core’s GPIO
04:11
digital output voltage to trigger it from the Core 110.
04:15
One important thing to note is all of these connections have a resettable fuse.
04:20
If you accidently use too much current an a given output and it seems to stop working altogether,
04:26
you can always reboot the Core to reset the fuse.
04:29
In terms of performance criteria for GPIO connections,
04:33
please reference the help file which lists all the details of the various configurations
04:38
such as volt tolerances for low logic signals for example are below 0.8V.
04:45
A logic high input is going to need 2 Volts or above.
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You’ll also find Additional information includes minimum and maximum voltages,
04:53
current capabilities, and output impedance.
04:57
As for the relays, maximums of 30 Volts and 1 Amp are sufficient for most applications.
05:03
Power pins are approximately 12 Volts, and with a maximum output current of 400 mA.
05:10
So with most LEDs, you can power quite a few of them with the available 400 mA of current.
05:16
If you look at the Core 110f, you’ll find that it’s much easier to connect using the phoenix connector.
05:22
On the back you will find the 12 Volt connections, ground, and the 16 GPIO inputs and 16 outputs.
05:30
These connections can be configured for digital, analog or potentiometer connections,
05:36
and then there is also a raw mode that we'll talk about a little bit later.
05:40
The outputs have three configurations: 3.3 Volt TTL,
05:45
open collector with a 24 Volt and 200mA maximum current sync,
05:50
and again, the same resettable fuses.
05:53
GPIO connections on the IO8 Flex are essentially the same, except that you have 8 instead of 16.
05:59
GPIO on QSC networked amplifiers are a little bit different as they mimic
06:05
the core with a relay and typical GPIO pin on the phoenix connector.
06:09
These connections can be configured for driving LED’s,
06:12
but keep in mind these only have 18mA of current in this case.
06:17
These connections can also accept potentiometer, contact closure,
06:22
or TTL, but no open collector or raw configurations are available on the amplifiers.
06:27
Now let’s look at that raw configuration mentioned earlier.
06:31
For troubleshooting GPIO connections,
06:33
you can temporarily configure the pin in this raw state to expose more controls and information.
06:39
As an input, you can check the present voltage, and enable TTL high current.
06:44
In this mode, the DA15 connector provides the most possibilities to configure
06:49
the pins as inputs and outputs or enable the pull-down, internally.
06:54
Keep in mind that the Core 110f and the IO-8 Flex have dedicated inputs and outputs,
07:00
but all other controls are still available.
07:03
If you are troubleshooting,
07:04
you can use this RAW mode to better understand the signal levels and whether
07:09
it fits the behavior and the limits for your GPIO configuration.
07:12
One of the most common GPIO applications is to connect them to microphone LEDs and mute buttons.
07:19
Every microphone model can be slightly different,
07:21
so it is important to identify if the microphone responds to a contact closure or if a TTL signal is required.
07:29
Also, some microphones will use phantom power
07:32
and provide a voltage for LEDs on their own, while others will not.
07:37
For example, the Shure MX392 has a dip switch settings that can be configured
07:42
whether it's going to be a momentary or toggle mute button.
07:46
You also have a simple LED operation control.
07:50
Then you have the Shure MX396 with two or three microphone elements.
07:55
This mic provides multiple audio signals that will need to connect to the core.
08:00
There is also a single switch connection, and a single output to the LED,
08:05
and then a ground connection.
08:06
If we output a digital high to this microphone,
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the LED will show red, and if you output a digital low, the microphone will turn green.
08:15
Here’s an example design of the MX396,
08:18
which has some custom controls to test the logic circuit downstream.
08:22
This trigger combiner allows me to press any of the microphone buttons
08:26
to act as one overall privacy or mute control.
08:29
If you're in mute mode then you turn all the LEDs of all the microphones in the system
08:34
to red so that everybody knows that the mics are muted.
08:38
By contrast, here is a microphone example by Clock Audio.
08:42
Unlike the Shure MX396, this microphone does not use phantom power for the LED’s,
08:47
so you need to provide a 12 Volt power supply which, as you can see, increases the complication of the wiring.
08:54
These microphones have RJ45 connectors on the CAT5 for the microphones themselves.
08:59
In this system, we will need to consolidate all your 12 Volt power and ground connections back
09:05
to the Core which can power 6 of these microphones,
09:09
and then distribute the green and red LED logic and the individual button wiring to the GPIO connections.
09:16
For troubleshooting GPIO, you should start at the beginning by asking a few vital questions, like
09:23
“what device is providing the voltage?” At what levels are my voltages?
09:28
If I'm configured as an output, what device is syncing the current?
09:33
And is that sync current flowing in the right direction
09:37
(remember that the GPIO transistors only allow current to flow to ground and not the opposite direction.)
09:44
Then, am I syncing an acceptable amount of current?
09:48
How many LEDs am I trying to drive with the existing GPIO current configuration.
09:53
Also, what is the normal state of this device, meaning is my relay normally open or is it normally closed.
10:01
For these questions, your friend the voltmeter, is very useful.
10:05
What often happens with GPIO applications is the signal flow is created by one person,
10:11
the wiring is done by another person,
10:13
and then you have the programmer that comes in and sends the device file with all the logic.
10:19
And if things then don't work immediately,
10:21
the programmer starts rearranging logic blocks and the signal flow,
10:25
rather than troubleshooting systematically from the beginning
10:28
to see whatQ-SYS sees when I push this button.
10:33
Okay, GPIO was a big one.
10:36
Sorry about that! Let’s break right there and when we get back, we’ll look at Q-SYS Ethernet control
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Introduction to Q-SYS Control (Part 3)
10m 45s