PCI/PXI/PCIe-6509 User Guide and Specifications
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© National Instruments
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is connected to the system. Avoid contact between your body and the connector block signal
when hot swapping modules. Remove power from signal lines before connecting them to or
disconnecting them from the DIO device.
Operate the DIO device at or below the
measurement category
1
marked on the hardware label.
Measurement circuits are subjected to
working voltages
2
and transient stresses (overvoltage)
from the circuit to which they are connected during measurement or test. Installation categories
establish standard impulse withstand voltage levels that commonly occur in electrical
distribution systems. The following is a description of installation categories:
•
Measurement Category I is for measurements performed on circuits not directly connected
to the electrical distribution system referred to as MAINS
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voltage. This category is for
measurements of voltages from specially protected secondary circuits. Such voltage
measurements include signal levels, special equipment, limited-energy parts of equipment,
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. 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 DIO 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.
Electromagnetic Compatibility Guidelines
This product was tested and complies with the regulatory requirements and limits for
electromagnetic compatibility (EMC) as stated in the product specifications. These requirements
and limits are designed to provide reasonable protection against harmful interference when the
product is operated in its intended operational electromagnetic environment. There is no
guarantee that interference will not occur in a particular installation. To minimize the potential
for the product to cause interference to radio and television reception or to experience
unacceptable performance degradation, install and use this product in strict accordance with the
instructions in the product documentation.
1
Measurement categories, also referred to as
installation categories
, are defined in electrical safety standard
IEC 61010-1.
2
Working voltage is the highest rms value of an AC or DC voltage that can occur across any particular
insulation.
3
MAINS is defined as a hazardous live electrical supply system that powers equipment. Suitably rated
measuring circuits may be connected to the MAINS for measuring purposes.
