©
National Instruments Corp.
11
FP-DI-330 and cFP-DI-330
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-DI-330.
Even though the [c]FP-DI-330 is designed to handle applications
with hazardous potentials, follow these guidelines to ensure a safe
total system:
•
There is no safety isolation between channels on the
[c]FP-DI-330. 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.
•
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
backplane PE ground terminal to the system safety ground
using 14 AWG (1.6 mm) wire with a ring lug. Use the 5/16 in.
panhead screw shipped with the backplane to secure the ring
lug to the backplane PE ground terminal.
•
As with any hazardous voltage wiring, make sure that all
wiring and connections meet applicable electrical codes and
commonsense practices. Mount terminal bases and backplanes
in an area, position, or cabinet that prevents accidental or
unauthorized access to wiring that carries hazardous voltages.
•
Do
not
use the [c]FP-DI-330 as the only isolating barrier
between human contact and working voltages higher than
250 V
rms
.
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.
