Digital I/O 1&2
Each I/O port is capable of being used in one of two different configurations; Digital Input, and Digital
Output. These modes of operation can be configured in the built in setup pages of the NXT-700 or via
RPC commands.
Digital Input
The Digital Input is used to read a digital voltage level. It can read 0V (=0) or 3V (=1). Higher voltages
are clamped to 3V. The digital input is perfect for applications requiring simple on/off detection such a
contact switch. By default the port is high impedance for the most flexibility. The setup page can also
allow a pull-up configuration. If the port is left as is then the device connected to the digital input must
supply the high and low voltages.
You can see the state of the Digital Input port using the DIO diagnostic page or through an RPC method
call.
Digital Output
The Digital Output is used as an open drain and can sink up to 200ma. Setting the port to 0 will leave sink
the input to ground. Setting the port as a 1 will put the port into a high impedance state. The digital
output can be used for triggering relays, LEDs, or any device that will not require more then 200ma of
current.
You can change the state of the Digital Output port using the DIO diagnostic page or through an RPC
method call.
I/O GROUND Line
To operate properly, the device connected to the input port must be connected to both the GND line of the
connector block as well as one of the two input ports.
LED Indicators for I/O Ports (1&2)
The LEDs indicate that the voltage is on the port. It will be either on (voltage present) or off (no voltage
or less than 1V).
IR Ports
The two (2) IR ports on the NXT-700 are used to send infrared commands to devices that can be
controlled using a standard IR remote control. To control a device, connect one of the IR emitters to the
IR sensor of the device to be controlled. In addition the IR port can be used a one way RS-232C (TX
only) at rates up to 115k.
