Connecting Devices To The Auxiliary Input Signals - Matrox Indio Installation And Hardware Reference

36 Chapter 2: Hardware installation
aux_in+
Sensing
circuit
aux_in-
Sinking to ground
Connecting a sourcing output device
to a sinking auxiliary input signal
Equivalent circuit only

Connecting devices to the auxiliary input signals

Matrox Indio auxiliary input signals can be interfaced with a wide variety of devices
(such as proximity detectors). The Matrox Indio auxiliary input signals only detect
when current flows from their AUX_IN+ pin to their AUX_IN- pin. As such, an
auxiliary input signal must be connected to a device that controls the flow of
current. When current is detected, the signal is reported as on; otherwise, it is
reported as off. In software, you can enable an interrupt to be generated the
moment current is detected. For information on the electrical specifications of the
on and off voltage levels, see the Electrical specifications section, in Appendix B:
Technical information.
You can connect the auxiliary input signals in a sinking or sourcing configuration.
The exact connection between the input signal, the connected device, and the
power source depends entirely on the type of device to which you connect. You
should essentially connect your device respecting the following:
Vcc
Sourcing from Vcc
Vcc
aux_in+
Sensing
circuit
aux_in-
Sourcing from Vcc
Connecting a sinking output device
to a sourcing auxiliary input signal
Sinking to ground