sh030051g.pdf - 第282页

11 - 77 11. OPTIONS AND AUXILI ARY EQUIPMENT (c) Techniques for noises radiated by the servo ampl ifier tha t cause peripheral devices to malfunction Noises produced by the servo amplifier are classified into those radia…

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11 - 76
11. OPTIONS AND AUXILIARY EQUIPMENT
11.16 Surge absorbers (recommended)
A surge absorber is required for the electromagnetic brake. Use the following surge absorber or equivalent.
When using the surge absorber, perform insulation beforehand to prevent short-circuit.
Maximum rating
Maximum
limit voltage
Static capacity
(reference
value)
Varistor voltage
rating (range) V1mA
Permissible circuit
voltage
Surge
immunity
Energy
immunity
Rated
power
AC[Vma] DC[V] [A] [J] [W] [A] [V] [pF] [V]
140 180
(Note)
500/time
5 0.4 25 360 300
220
(198 to 242)
Note. 1 time 8 20 s
13.5
1
6
.
5
4.7 1.0
0.8
3.0 or less
30.0 or more
[Unit: mm]
(Example) ERZV10D221 (Matsushita Electric Industry)
TNR-10V221K (Nippon chemi-con)
Outline drawing [mm] (ERZ-C10DK221)
11.17 Noise reduction techniques
Noises are classified into external noises which enter the servo amplifier to cause it to malfunction and those
radiated by the servo amplifier to cause peripheral devices to malfunction. Since the servo amplifier is an
electronic device which handles small signals, the following general noise reduction techniques are required.
Also, the servo amplifier can be a source of noise as its outputs are chopped by high carrier frequencies. If
peripheral devices malfunction due to noises produced by the servo amplifier, noise suppression measures
must be taken. The measures will vary slightly with the routes of noise transmission.
(1) Noise reduction techniques
(a) General reduction techniques
Avoid laying power lines (input and output cables) and signal cables side by side or do not bundle
them together. Separate power lines from signal cables.
Use shielded, twisted pair cables for connection with the encoder and for control signal transmission,
and connect the shield to the SD terminal.
Ground the servo amplifier, servo motor, etc. together at one point (refer to section 3.12).
(b) Reduction techniques for external noises that cause the servo amplifier to malfunction
If there are noise sources (such as a magnetic contactor, an electromagnetic brake, and many relays
which make a large amount of noise) near the servo amplifier and the servo amplifier may malfunction,
the following countermeasures are required.
Provide surge absorbers on the noise sources to suppress noises.
Attach data line filters to the signal cables.
Ground the shields of the encoder connecting cable and the control signal cables with cable clamp
fittings.
Although a surge absorber is built into the servo amplifier, to protect the servo amplifier and other
equipment against large exogenous noise and lightning surge, attaching a varistor to the power input
section of the equipment is recommended.
11 - 77
11. OPTIONS AND AUXILIARY EQUIPMENT
(c) Techniques for noises radiated by the servo amplifier that cause peripheral devices to malfunction
Noises produced by the servo amplifier are classified into those radiated from the cables connected to
the servo amplifier and its main circuits (input and output circuits), those induced electromagnetically or
statically by the signal cables of the peripheral devices located near the main circuit cables, and those
transmitted through the power supply cables.
Noises produced
by servo amplifier
Noises transmitted
in the air
Noise radiated directly
from servo amplifier
Magnetic induction
noise
Static induction
noise
Noises transmitted
through electric
channels
Noise radiated from the
power supply cable
Noise radiated from
servo motor cable
Noise transmitted through
power supply cable
Noise sneaking from
grounding cable due to
leakage current
Routes 4) and 5)
Route 1)
Route 2)
Route 3)
Route 7)
Route 8)
Route 6)
Instrument Receiver
Servo
amplifier
Servo motor M
2)
2)
8)
1)
7)
7) 7)
5)
3)
4)
6)
3)
Sensor
power
supply
Sensor
11 - 78
11. OPTIONS AND AUXILIARY EQUIPMENT
Noise transmission route Suppression techniques
1) 2) 3)
When measuring instruments, receivers, sensors, etc. which handle weak signals and may malfunction
due to noise and/or their signal cables are contained in a control box together with the servo amplifier or
run near the servo amplifier, such devices may malfunction due to noises transmitted through the air. The
following techniques are required.
1. Provide maximum clearance between easily affected devices and the servo amplifier.
2. Provide maximum clearance between easily affected signal cables and the I/O cables of the servo
amplifier.
3. Avoid laying the power lines (Input cables of the servo amplifier) and signal cables side by side or
bundling them together.
4. Insert a line noise filter to the I/O cables or a radio noise filter on the input line.
5. Use shielded wires for signal and power cables or put cables in separate metal conduits.
4) 5) 6)
When the power lines and the signal cables are laid side by side or bundled together, magnetic
induction noise and static induction noise will be transmitted through the signal cables and malfunction
may occur. The following techniques are required.
1. Provide maximum clearance between easily affected devices and the servo amplifier.
2. Provide maximum clearance between easily affected signal cables and the I/O cables of the servo
amplifier.
3. Avoid laying the power lines (I/O cables of the servo amplifier) and signal cables side by side or
bundling them together.
4. Use shielded wires for signal and power cables or put the cables in separate metal conduits.
7)
When the power supply of peripheral devices is connected to the power supply of the servo amplifier
system, noises produced by the servo amplifier may be transmitted back through the power supply
cable and the devices may malfunction. The following techniques are required.
1. Insert the radio noise filter (
FR-BIF-(H)
) on the power cables (Input cables) of the servo amplifier.
2. Insert the line noise filter (FR-BSF01
FR-BLF) on the power cables of the servo amplifier.
8)
When the cables of peripheral devices are connected to the servo amplifier to make a closed loop
circuit, leakage current may flow to malfunction the peripheral devices. If so, malfunction may be
prevented by disconnecting the grounding cable of the peripheral device.
(2) Noise reduction products
(a) Data line filter (Recommended)
Noise can be prevented by installing a data line filter onto the encoder cable, etc. For example, the
ZCAT3035-1330 of TDK and the ESD-SR-25 of NEC TOKIN make are available as data line filters. As a
reference example, the impedance specifications of the ZCAT3035-1330 (TDK) are indicated below.
This impedances are reference values and not guaranteed values.
Impedance[ ]
Outline drawing (ZCAT3035-1330)
[Unit: mm]
Loop for fixing the
cable band
Lot number Product name
TDK
39 1
34 1
1
3
1
3
0
1
10 to 100MHz 100 to 500MHz
80 150