Programming instructions

Chapter 18 NI 435X Devices
DAQ Hardware Overview Guide 18-4 www.ni.com
NI 435 X Current Source
The NI 435X device has a built-in 25 µA current source (exact value stored
on board). You can use it to provide excitation to RTDs, thermistors, and
other resistors. Use the ohms mode to make measurements using the
current source. NI 4351 devices also have an addition 1 mA current source
for more accurate measurements with RTDs.
NI 435 X Digital I/O
The NI 4350 for PCMCIA has one 4-bit digital port. The NI 435X for ISA,
USB, PCI, and PXI has one 8-bit digital port. These ports are referred to as
port 0 by the digital I/O functions.
You can configure the entire digital port as either input or output, or you can
configure individual lines for either input or output. The port has read-back
capability (that is, by reading the port, you can determine what digital value
the outport port is currently asserting). This port operates in a nonlatched
mode only.