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Technical 

Notes

Q-SYS Core 110f

Rev. B, 14 November 2017

Using the GPIO inputs and outputs

The Q-SYS Core 110f features General Purpose Input/Output (GPIO) connections that allow the core to interface with 
miscellaneous outside devices, such as LED indicators, switches, relays, and potentiometers, and with custom or third-
party controls. The GPIO allotment on the Core 110f totals 16 inputs and 16 outputs. Use Q-SYS Designer to select the 
type of input or output and configure it. Each GPIO input and output is independent of the others.

Flanking each row of eight GPIO inputs and outputs is a +12 V DC terminal (up to 200 mA available on each, protected 
by a self-resetting fuse) and a ground or reference terminal. This can be used for potentiomenters (input), relay coils and 
LEDs (output), and other uses.

GPIO configurations

These are the various ways that GPIO inputs and outputs can be configured.

Type

Conceptual schematic

Control pins

Notes

Input

Digital Input (TTL 3.3 V)—

The input is fed by a 3.3 

V TTL digital source. The two states are logic high (1) 
and logic low (0).

None

Contact Closure Input—

This setting enables an in-

ternal pull-up resistor, allowing actuation by a contact 
closure to ground. This can be through a switch, set of 
relay contacts, etc.

None

Internal pull-up resistor 
to +12 V. When contacts 
are closed, GPIO In = 0 V; 
when open, GPIO In = 
+12 V.

Potentiometer (10 kΩ, 12 V)—

In this setting, the 

external potentiometer acts as a variable voltage 
divider. The GPIO input reads the voltage delivered. The 
ground terminal is the reference. The GPIO interprets 
the voltage as a proprtion between the minimum and 
maximum pot positions, with better resolution and 
accuracy than the two-wire potentiometer configura-
tion offers. This configuration requires calibration of 
the pot’s minimum and maximum positions.

Calibrate Maximum

Calibrate Minimum

Maximum Position

Minimum Position

Calibrate the minimum 
and maximum positions of 
the pot.

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