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Chapter 2 Setup and Configuration
© National Instruments Corporation 2-5 NI CVS-1450 Series User Manual
• Pollution Degree 3—Conductive pollution or dry, nonconductive
pollution occurs. Nonconductive pollution becomes conductive
because of condensation.
Clean the device and accessories by brushing off light dust with a soft,
nonmetallic brush. Remove other contaminants with a stiff, nonmetallic
brush. The unit must be completely dry and free from contaminants before
returning it to service.
You must insulate signal connections for the maximum voltage for which
the device is rated. Do not exceed the maximum ratings for the device.
Remove power from signal lines before connection to or disconnection
from the device.
Caution National Instruments measurement products may be classified as either
Measurement Category I or II. Operate this device at or below the Measurement Category
level specified in the hardware specifications.
Measurement Category
1
: 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 Category establishes
standardized impulse withstand voltage levels that commonly occur in
electrical distribution systems. The following is a description of Installation
(Measurement
3
) Categories:
• Measurement Category I is for measurements performed on circuits
not directly connected to the electrical distribution system referred to
as MAINS
4
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 (e.g., 115 V for U.S. or 230 V for Europe).
1
Measurement Categories as 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
Measurement Category is also referred to as Installation Category.
4
MAINS is defined as the (hazardous live) electrical supply system to which equipment is designed to be connected for the
purpose of powering the equipment. Suitably rated measuring circuits may be connected to the MAINS for measuring
purposes.