©National Instruments Corporation 3 Getting Started with the NI PCIe-8253
levels, special hardware, limited-energy parts of hardware, circuits powered by regulated
low-voltage sources, and electronics.
• Measurement Category II is for measurements performed on circuits directly connected to the
electrical distribution system (MAINS3). This category refers to local-level electrical distribution,
such as that provided by a standard wall outlet (for example, 115 AC voltage for U.S. or 230 AC
voltage for Europe). Examples of Measurement Category II are measurements performed on
household appliances, portable tools, and similar hardware.
• Measurement Category III is for measurements performed in the building installation at the
distribution level. This category refers to measurements on hard-wired hardware such as hardware
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 typically outside buildings. Examples include electricity meters and measurements on
primary overcurrent protection devices and on ripple control units.
To obtain the safety certification(s) for this product, visit ni.com/certification, search by model
number or product line, and click the appropriate link in the Certification column.
Electromagnetic Compatibility Information
This hardware has been tested and found to comply with the applicable regulatory requirements
and limits for electromagnetic compatibility (EMC) as indicated in the hardware’s Declaration of
Conformity (DoC)1. These requirements and limits are designed to provide reasonable protection
against harmful interference when the hardware is operated in the intended electromagnetic
environment. In special cases, for example when either highly sensitive or noisy hardware is being used
in close proximity, additional mitigation measures may have to be employed to minimize the potential
for electromagnetic interference.
While this hardware is compliant with the applicable regulatory EMC requirements, there is no
guarantee that interference will not occur in a particular installation. To minimize the potential for
the hardware to cause interference to radio and television reception or to experience unacceptable
performance degradation, install and use this hardware in strict accordance with the instructions in
the hardware documentation and the DoC1.
If this hardware does cause interference with licensed radio communications services or other nearby
electronics, which can be determined by turning the hardware off and on, you are encouraged to try to
correct the interference by one or more of the following measures:
• Reorient the antenna of the receiver (the device suffering interference).
• Relocate the transmitter (the device generating interference) with respect to the receiver.
• Plug the transmitter into a different outlet so that the transmitter and the receiver are on different
branch circuits.
Some hardware may require the use of a metal, shielded enclosure (windowless version) to meet the
EMC requirements for special EMC environments such as, for marine use or in heavy industrial areas.
Refer to the hardware’s user documentation and the DoC1for product installation requirements.
1 The Declaration of Conformity (DoC) contains important EMC compliance information and instructions for the user or
installer. To obtain the DoC for this product, visit ni.com/certification, search by model number or product line,
and click the appropriate link in the Certification column.
