© National Instruments Corporation 5 NI USB-6008/6009 User Guide and Specifications
• Measurement Category II is for measurements performed on circuits
directly connected to the electrical distribution system. This category
refers to local-level electrical distribution, such as that provided by a
standard wall outlet (for example, 115 V for U.S. or 230 V for Europe).
Examples of Measurement Category II are measurements performed
on household appliances, portable tools, and similar E Series devices.
• Measurement Category III is for measurements performed in the
building installation at the distribution level. This category refers to
measurements on hard-wired equipment such as equipment in fixed
installations, distribution boards, and circuit breakers. Other examples
are wiring, including cables, bus-bars, junction boxes, switches,
socket-outlets in the fixed installation, and stationary motors with
permanent connections to fixed installations.
• Measurement Category IV is for measurements performed at the
primary electrical supply installation (<1,000 V). Examples include
electricity meters and measurements on primary overcurrent
protection devices and on ripple control units.
Related Documentation
Each application software package and driver includes information about
writing applications for taking measurements and controlling measurement
devices. The following references to documents assume you have
NI-DAQmx8.7 or later, and where applicable, version 7.1 or later of the
NIapplication software.

NI-DAQmx for Windows

The DAQ Getting Started Guide describes how to install your NI-DAQmx
for Windows software, how to install your NI-DAQmx-supported DAQ
device, and how to confirm that your device is operating properly. Select
Start»All Programs»National Instruments»NI-DAQ»DAQ Getting
Started Guide.
The NI-DAQ Readme lists which devices are supported by this version of
NI-DAQ. Select Start»All Programs»National Instruments»NI-DAQ»
NI-DAQ Readme.
The NI-DAQmx Help contains general information about measurement
concepts, key NI-DAQmx concepts, and common applications that are
applicable to all programming environments. Select Start»All Programs»
National Instruments»NI-DAQ»NI-DAQmx Help.
Note For information about non-Windows operating system support, refer to ni.com/
info and enter BaseGSGML.