National Instruments Signal Processing Engineering Educational Device NI SPEEDY-33 User Manual
Page 10
Chapter 1
NI SPEEDY-33 Overview
© National Instruments Corporation
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Operate the module only at or below Pollution Degree 2. Pollution is
foreign matter in a solid, liquid, or gaseous state that can reduce dielectric
strength or surface resistivity. The following is a description of pollution
degrees:
•
Pollution Degree 1 means no pollution or only dry, nonconductive
pollution occurs. The pollution has no influence.
•
Pollution Degree 2 means that only nonconductive pollution occurs in
most cases. Occasionally, however, a temporary conductivity caused
by condensation must be expected.
•
Pollution Degree 3 means that conductive pollution occurs, or dry,
nonconductive pollution occurs that becomes conductive due to
condensation.
You must insulate signal connections for the maximum voltage for which
the module is rated. Do not exceed the maximum ratings for the module.
Do not install wiring while the module is live with electrical signals. Do not
remove or add connector blocks when power 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 module.
Operate the module 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. Measurement categories establish
standard impulse withstand voltage levels that commonly occur in
electrical distribution systems. The following is a description of
measurement categories:
•
Measurement Category I is for measurements performed on circuits
not directly connected to the electrical distribution system referred
to as MAINS
3
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
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.