Mitsubishi Electric NZ2GFCF-D62PD2 User Manual page 73

(4) Measures against noise
• The high-speed counter module may incorrectly count the pulses when pulse-state noises are input.
• When inputting high-speed pulses, take the following measures against noise.
Measure 1
Use shielded twisted pair cables, and ground them on the encoder side with a ground
resistance of 100
Measure 2
Use the shortest possible shielded twisted pair cables, placing them not parallel with
noise-generating power cables or I/O cables and at a distance of 150mm or more.
• The following figure shows an example of a noise reduction measure.
High-speed
counter module
High-speed counter module
Ground shielded twisted pair cables on the encoder side.
Use the shortest possible shielded cables.
Inverter
Terminal Terminal
block block
Avoid using a solenoid valve or inductive load together with the cable in a metallic pipe.
If a sufficient distance from the power line cannot be ensured due to duct wiring,
use shielded cables such as CVVS for the power line.
Install a cable at least
150mm away from
the I/O cable of a high
voltage equipment such
as a relay or inverter.
(Pay attention to wiring
in the control panel as
well.)
AC
Cart
motor
• Ground the shielded twisted pair cable on the encoder side (relay box). (Wiring example: with a sink type
encoder (24V))
Current for encoder
To A
To B
To the high-speed
counter module
or less.
Keep a shortest distance between the encoder and relay box.
Relay box
If the distance from the high-speed counter module to the encoder is long,
a voltage drop may occur. Using a measuring instrument such as
a synchroscope on the terminal block of the relay box, check that the voltages
in the encoder operation and stop status are within the rated voltage range.
If a voltage drop is too large, increase the cable size or use a 24VDC
encoder that will consume less current.
Encoder
+24V
To the encoder
0V
A
B
Connect the shielded cable of the encoder to the shielded cable
24V
of the shielded twisted pair cable in the relay box. If the shielded
E
cable of the encoder is not grounded in the encoder, ground it to
the relay box as shown by the dotted lines.
E
CHAPTER 6 INSTALLATION AND WIRING
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