Isolation And Safety Guidelines - National Instruments FieldPoint FP-PWM-520 Operating Instructions Manual

Isolation and Safety Guidelines

Caution
contain hazardous voltages to the FP-PWM-520, read
the following information.
This section describes the isolation of the FP-PWM-520 and its
compliance with international safety standards. The outputs are
isolated from the backplane provided by the terminal base with an
optical isolation barrier designed and tested to provide protection
against fault voltages of up to 3,000 Vrms. In addition, the
FP-PWM-520 provides double insulation (compliant with UL and
IEC safety standards) for working common-mode voltages of
250 Vrms. Safety standards (such as those published by UL and
IEC) require the use of double insulation between hazardous
voltages and any human-accessible parts or circuits.
Never try to use any isolation product between human-accessible
parts (such as DIN rails or monitoring stations) and circuits that
may be at hazardous potentials under normal conditions, unless the
product is specifically designed for such an application, as is the
FP-PWM-520.
When you use a product like the FP-PWM-520 in applications with
hazardous potentials, follow these guidelines to make sure your
total system is safe:
• The safety isolation of the FP-PWM-520 is from input to
output, not between channels on the same module. If any of the
channels on a module are wired at a hazardous potential, make
sure that all other devices or circuits connected to that module
are properly insulated from human contact.
• Do not share the external supply voltages (V, C, V
terminals on the terminal base) with other devices (including
other FieldPoint devices), unless those devices are isolated
from human contact.
• As with any hazardous voltage wiring, make sure that all
wiring and connections meet with applicable electrical codes
and common sense practices. Mount terminal bases in an area,
position, or cabinet that prevents accidental or unauthorized
access to wiring that carries hazardous voltages.
• The isolation of the FP-PWM-520 is certified as
double-insulated for normal operating voltages of 250 Vrms.
Do not use the FP-PWM-520 as the only isolating barrier
between human contact and working voltages of more than
250 Vrms.
© National Instruments Corp.
Before you connect any circuits that may
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