©
National Instruments Corp.
7
FP-AI-102 and cFP-AI-102
Isolation and Safety Guidelines
Caution
Read the following information before
attempting to connect the [c]FP-AI-102 to any circuits
that may contain hazardous voltages.
This section describes the isolation of the [c]FP-AI-102 and its
compliance with international safety standards. The field wiring
connections are isolated from the backplane and the inter-module
communication bus. The isolation is provided by the module,
which has optical and galvanic isolation barriers designed and
tested to protect against transient fault voltages of up to 2,300 V
rms
.
The [c]FP-AI-102 provides
double insulation
(compliant with
IEC 61010-1) for working voltages of 250 V
rms
1
. 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
[c]FP-AI-102.
Even though the [c]FP-AI-102 is designed to handle applications
with hazardous potentials, follow these guidelines to ensure a safe
total system:
•
The [c]FP-AI-102 has a safety isolation barrier between the
inter-module communication bus and the I/O channels. There
is no isolation between channels unless otherwise noted. 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 (the V and C
terminals) with other devices (including other FieldPoint
devices), unless those devices are isolated from human contact.
•
For Compact FieldPoint, you
must
connect the protective earth
(PE) ground terminal on the cFP-BP-
x
backplane to the system
safety ground. The backplane PE ground terminal has the
following symbol stamped beside it:
. Connect the
1
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.