Chapter 5 Signal Connections
© National Instruments Corporation 5-17 NI 7350 User Manual
Bits 2–7 in DIO ports 4 and 8 are dual-purpose bits that can be used
for either general-purpose I/O or Hall sensor feedback during system
configuration and initialization, but not both. When you set these bits to
provide Hall sensor feedback, they are reserved for this activity and cannot
be used for general-purpose I/O until you reinitialize the motion system.
All digital I/O lines have programmable direction and polarity.
The DPull(P1:P4) and DPull(P5:P8) pins control the state of the digital
input pins at power-up.
Connecting DPull(P1:P4) to +5 V or leaving it unconnected configures all
pins in ports 1–4 for 10 kΩ pull-ups. Connecting DPull(P1:P4) to ground
configures these ports for 10 kΩ pull-downs.
Connecting DPull(P5:P8) to +5 V or leaving it unconnected configures all
pins in ports 5–8 for 10 kΩ pull-ups. Connecting DPull(P5:P8) to ground
configures these ports for 10 kΩ pull-downs.
PWM Features
The NI 7350 controller provides two pulse width modulation (PWM)
outputs on the digital I/O connector for ports 1–4. The PWM outputs
generate periodic waveforms whose period and duty cycles can be
independently controlled through software commands. You can compare
PWM to a digital representation of an analog value, because the duty cycle
is directly proportional to the desired output value. PWM outputs are
typically used for transmitting an analog value through an optocoupler. A
simple lowpass filter turns a PWM signal back into its corresponding
analog value. Ifappropriate, you can use an external clock source
connected to the PCLK input instead of the internal source as the clock for
the PWM generators.
Note These signals are configured in software and are in no way associated with the
PID servo control loop. Refer to the Measurement & Automation Explorer Help for
Motion, the NI-Motion Function Help, or the NI-Motion VI Help for more information.