National Instruments cFP-PWM-520 用户手册

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页码 19
FP-PWM-520 and cFP-PWM-520
10
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Even though the [c]FP-PWM-520 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 
[c]FP-PWM-520. 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-PWM-520 as the only isolating barrier 
between human contact and working voltages higher than 
250 V
rms
.
Operate the [c]FP-PWM-520 only at or below Pollution 
Degree 2. Pollution Degree 2 means that only nonconductive 
pollution occurs in most cases. Occasionally, however, a 
temporary conductivity caused by condensation must be 
expected.
Operate the [c]FP-PWM-520 at or below Measurement 
Category II. Measurement Category II is for measurements 
performed on circuits directly connected to the low-voltage 
installation. This category refers to local-level distribution, 
such as that provided by a standard wall outlet.