5019T Flat Panel Industrial Touch Monitor Chapter 2 – Installation
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143627(A)
Electrical Noise
Electrical noise is seldom responsible for damaging components, unless
extremely high energy or high voltage levels are present. However, noise can
cause temporary malfunctions that can result in hazardous machine
operation in certain applications. Noise may be present only at certain times,
may appear at widely spread intervals, or in some cases may exist
continuously.
Noise commonly enters through input, output, and power supply lines and
may also be coupled through the capacitance between these lines and the
noise signal carrier lines. This usually results from the presence of high
voltage or long, close-spaced conductors. When control lines are closely
spaced with lines carrying large currents, the coupling of magnetic fields can
also occur. Use shielded cables to help minimize noise. Potential noise
generators include switching components, relays, solenoids, motors, and
motor starters.
Refer to the relevant Federal, State/Provincial, and local electric codes, which
provide data such as the size and types of conductors, color codes and
connections necessary for safe grounding of electrical components. It is
recommended that high- and low-voltage cabling be separated and dressed
apart. In particular, AC cables and switch wiring should not be in the same
conduit with all communication cables.
Line Voltage Variation
The power supply section of the unit is built to sustain the specified line
fluctuations and still allow the system to function in its operating margin. As
long as the incoming voltage is adequate, the power supply provides all the
logic voltages necessary to support the monitor unit.
Unusual AC line variations may cause undesirable system shutdowns. As a
first step to reduce line variations, correct any possible feed problems in the
distribution system. If this correction does not solve the problem, use a
constant voltage transformer. The constant voltage transformer stabilizes the
input voltage to the systems by compensating for voltage changes at the
primary in order to maintain a steady voltage at the secondary. When using a
constant voltage transformer, check that the power rating is sufficient to
supply the unit.
