Excessive Noise; Excessive Line Voltage; Mounting The 9450 - Xycom 9450 Manual

When the air temperature is higher than 50º C in the enclosure, use a fan or air condi-
tioner.

Excessive Noise

Electrical noise is seldom responsible for damaging components, unless extremely high
energy or high voltage levels are present. However, noise can cause temporary malfunc-
tions due to operating errors, which 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 usually enters through input, output, and power supply lines and may be coupled
into lines electrostatically through the capacitance between these lines and the noise sig-
nal carrier lines. This usually results from the presence of high voltage or long, closed-
spaced conductors. When control lines are closely spaced with lines carrying large cur-
rents, the coupling of magnetic fields can also occur. Use shielded cables to help mini-
mize noise. Potential noise generators include relays, solenoids, motors, and motor start-
ers, especially when operated by hand contacts like push buttons or selector switches. In
accordance with National Electric Code specifications, it is recommended that the high
voltage and low voltage cabling be separated and dressed apart. In particular, the AC ca-
bles and switch wiring should not be in the same conduit with the PLC communication
cables.

Excessive Line Voltage

The 9450's power supply section is built to sustain line fluctuations of 90-131 VAC or
182-226 VAC and still allow the system to function within its operating margin. As long
as the incoming voltage is adequate, the power supply provides all the logic voltages
necessary to support the processor, memory, and I/O.
In cases in which the installation is subject to unusual AC line variations, a constant
voltage transformer can be used to prevent the system from shutting down too often.
However, a first step toward the solution of the line variations is to correct any possible
feed problem in the distribution system. If this correction does not solve the problem, a
constant voltage transformer must be used.
The constant voltage transformer stabilizes the input voltage to the 9450 by compensat-
ing for voltage changes at the primary in order to maintain a steady voltage at the secon-
dary. When using a constant voltage transformer, check that the power rating is sufficient
to supply the 9450.

Mounting the 9450

Once the conditions in the preceding sections have been met, mount the 9450 by fol-
lowing the instructions below:
Chapter 2 - Testing
19