Fanuc Power Mate i-D/H Maintenance Manual

B63175EN/03
2. HARDWARE
225
The CNC has been steadily reduced in size using surfacemount and
custom LSI technologies for electronic components. The CNC also is
designed to be protected from external noise. However, it is difficult to
measure the level and frequency of noise quantitatively, and noise has
many uncertain factors. It is important to prevent both noise from being
generated and generated noise from being introduced into the CNC. This
precaution improves the stability of the CNC machine system.
The CNC component units are often installed close to the parts generating
noise in the power magnetics cabinet. Possible noise sources into the
CNC are capacitive coupling, electromagnetic induction, and ground
loops.
When designing the power magnetics cabinet, guard against noise in the
machine as described in the following section.
The cables used for the machine are classified as listed in the following table:
Process the cables in each group as described in the action column.
Group Signal line Action
Primary AC power line
Bind the cables in group A
Secondary AC power line
separately (Note 1) from groups B
A
AC/DC power lines (containing the
power lines for the servo and
spindle motors)
and C, or cover group A with an
electromagnetic shield (Note 2).
See Section 2.14.4 and connect
AC/DC solenoid
spark killers or diodes with the
solenoid and relay.
AC/DC relay
solenoid and relay.
DC solenoid (24VDC)
Connect diodes with DC solenoid
and relay.
DC relay (24VDC)
and relay.
Bind the cables in group B
DC power line
separately from group A, or cover
group B with an electromagnetic
B
DI/DO cable between the I/O Unit
and power magnetics cabinet
shield.
Separate group B as far from
Group C as possible.
DI/DO cable between the I/O Unit
and machine
Group C as possible.
It is more desirable to cover group
B with the shield.
Cable between the Power Mate i
and I/O Unit
Bind the cables in group C
separately from group A, or cover
Cable for position and velocity
feedback
group C with an electromagnetic
shield.
Cable between the Power Mate i
and spindle amplifier
Separate group C as far from
Group B as possible.
Cable for the position coder
Be sure to perform shield
C
Cable for the manual pulse
generator
processing in Section 2.14.5.
Cable between the Power Mate i
and the setting and display unit
RS232C and RS422 interface
cable
Cable for the battery
Other cables to be covered with
the shield
2.14
ACTION AGAINST
NOISE
2.14.1
Separating Signal
Lines

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