Revision A—12 September 2017
1
Q-SYS™ Peripheral
Technical Notes
I/O-8 FLEX
Using the GPIO inputs and outputs
The Q-SYS I/O-8 Flex features General Purpose Input/Output (GPIO) connections that allow the
Q-SYS network 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 I/O-8
Flex totals eight inputs and eight 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 100 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 internal 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 configuration 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.
