National Instruments FieldPoint cFP-DI-304, Руководство по эксплуатации

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© National Instruments Corp. 7 cFP-DI-304
Isolation and Safety Guidelines
Caution
Read the following information before
attempting to connect the cFP-DI-304 to any circuits
that may contain
hazardous voltages .
1
This section describes the isolation of the cFP-DI-304 and
its compliance with international safety standards. The field
wiring connections are isolated from the backplane and the
inter-module communication bus. The isolation barriers in the
module provide 250 V
rms
Measurement Category II continuous
channel-to-backplane and channel-to-ground isolation, verified
by a 2,300 V
rms
, 5 s dielectric withstand test.
2
The cFP-DI-304
provides double insulation compliant with IEC 61010-1 for
working voltages of 250 V
rms
.
3
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
can be at hazardous potentials under normal conditions, unless the
product is specifically designed for such an application, as is the
cFP-DI-304.
Even though the cFP-DI-304 is designed to handle applications
with hazardous potentials, follow these guidelines to ensure a safe
total system:
• There is no isolation between channels on the cFP-DI-304. If a
hazardous voltage is present on any channel, all channels are
considered hazardous. Make sure that all other devices and
circuits connected to the module are properly insulated from
human contact.
• Do not share the external supply voltages (the V and
C terminals) with other devices, including other FieldPoint
devices, unless those devices are isolated from human contact.
1
A hazardous voltage is a voltage greater than 42.4 V
peak
or 60 VDC. When a
hazardous voltage is present on any channel, all of the channels must be considered
to be carrying hazardous voltages. Ensure that all circuits connected to the module
are inaccessible to human touch.
2
Refer to the Safety Isolation Voltage section for more information about isolation on
the cFP-DI-304.
3
Working voltage is defined as the signal voltage plus the common-mode voltage.
Common-mode voltage is the voltage of the module with respect to ground.
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