User`s manual
171
CHAPTER 5 SETTINGS AND PROCEDURE BEFORE OPERATION
5
5.4 Wiring
5.4.1 Wiring precautions
(4) Measures against noise
• The QD65PD2 may incorrectly count the pulses when pulse-state noises are input.
• When inputting high-speed pulses, take the following measures against noise.
• The following figure shows an example of a noise reduction measure.
• Ground the shielded twisted pair cable on the encoder side (relay box). (Wiring example: with a sink type
encoder (24V))
Measure 1
Measure 2
Use shielded twisted pair cables, and ground them to the encoder side.
Always ground the FG and LG terminals to the protective ground conductor.
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.
Terminal
block
Programmable
controller
Install I/O wires at least
150mm away from the
high voltage equipment
such as a relay or
inverter. (Pay attention
to wiring in the control
panel as well.)
AC
motor
Relay
box
Cart
Avoid using a solenoid valve or inductive load together with the cable in the same 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.
Encoder
Inverter
Terminal
block
QD65PD2
Ground the shielded twisted pair cable on the encoder side. Set the shielded cable as short as possible.
Provide the shortest possible distance between the encoder and relay box.
If the distance from the QD65PD2 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 if the voltages in the encoder
operation and stop states are within the rated voltage range. If a voltage
drop is too large, increase the wire size or use a 24VDC encoder that will
consume less current.
To the QD65PD2
Current for encoder
A
B
24V
E
+24V
0V
E
To the encoder
Connect the shielded wire of the encoder to the shielded
wire of the shielded twisted pair cable in the relay box.
If the shielded wire of the encoder is not grounded,
ground it to the relay box as shown by the dotted lines.
To B
To A