YASKAWA SMG Series User manual

YASKAWA
YASKAWA
MANUAL NO. TSE-S800-16E
AC Servomotors and Driver
SGMG/SGMS/SGMD/SGM/SGMP Servomotors
SGDB Servopack

PREFACE
The rapid progress being made in today’s automation and information
technologies is resulting in a growing need for even more-advanced motion
control for future high-tech equipment. The end result is a need for devices
that can provide more-precise and quicker motion at higher speeds. Servo
control technology makes this possible. Launched by Yaskawa in 1993, the
ΣSeries consists of innovative AC Servos that were developed using
leading-edge servo control technology.
This manual covers all products in the ΣSeries, which feature superior
functions and performance. This manual was designed to provide
comprehensible information for users who are about to use a servo for the
first time as well as for users who already have experience in using servos.
This manual enables users to understand what Σ-Series AC Servos are all
about and how to design, install, operate, and maintain a servo system.
Keep this manual in a convenient location and refer to it whenever
necessary in operating and maintaining the servo system.
YASKAWA ELECTRIC CORPORATION
General Precautions
SSome drawings in this manual are shown with the protective cover or shields removed, in order to
describe the detail with more clarity. Make sure all covers and shields are replaced before operat-
ing this product.
SSome drawings in this manual are shown as typical example and may differ from the shipped
product.
SThis manual may be modified when necessary because of improvement of the product, modifica-
tion or changes in specifications.
Such modification is made as a revision by renewing the manual No.
STo order a copy of this manual, if your copy has been damaged or lost, contact your YASKAWA
representative listed on the last page stating the manual No. on the front cover.
SYASKAWA is not responsible for accidents or damages due to any modification of the product
made by the user since that will void our guarantee.

−iv −
NOTES FOR SAFE OPERATION
Read this manual thoroughly before installation, operation, maintenance or inspection of the AC Servo
Drives. In this manual, the NOTES FOR SAFE OPERATION are classified as “WARNING” or
“CAUTION”.
WARNING
Indicates a potentially hazardous situation which, if not avoided, could result in death or serious personal inju-
ry.
CAUTION
Indicates a potentially hazardous situation which, if not avoided, may result in minor or moderate personal
injury and/or damage to the equipment.
In some instances, items described in CAUTION may also result in a serious accident. In either case,
follow these important items.
.

−v−
WARNING
(WIRING)
SGrounding must be in accordance with the national code and consistent
with sound local practices.
Failure to observe this warning may lead to electric shock or fire.
(OPERATION)
SNever touch any rotating motor parts during operation.
Failure to observe this warning may result in personal injury.
(INSPECTION AND MAINTENANCE)
SBe sure to turn OFF power before inspection or maintenance.
Otherwise, electric shock may result.
SNever open the terminal cover while power is ON, and never turn ON pow-
er when the terminal cover is open.
Otherwise, electric shock may result.
SAfter turning OFF power, wait at least five minutes before servicing the
product.
Otherwise, residual electric charges may result in electric shock.
CAUTION
(RECEIVING)
SUse the specified combination of servomotor and SERVOPACK.
Failure to observe this caution may lead to fire or failure.
(INSTALLATION)
SNever use the equipment where it may be exposed to splashes of water,
corrosive or flammable gases, or near flammable materials.
Failure to observe this caution may lead to electric shock or fire.
(WIRING)
SDo not connect three−phase power supply to output terminals UV and
W.
Failure to observe this caution may lead to personal injury or fire.
SSecurely tighten screws on the power supply and motor output terminals.
Failure to observe this caution can result in a fire.

−vi −
CAUTION
(OPERATION)
STo avoid inadvertent accidents, run the servomotor only in test run (with-
out load).
Failure to observe this caution may result in personal injury.
SBefore starting operation with a load connected, set up parameters suit-
able for the machine.
Starting operation without setting up parameters may lead to overrun failure.
SBefore starting operation with a load connected, make sure emergency-
stop procedures are in place.
Failure to observe this caution may result in personal injury.
SDuring operation, do not touch the heat sink.
Failure to observe this caution may result in burns.
(INSPECTION AND MAINTENANCE)
SDo not disassemble the servomotor.
Failure to observe this caution may result in electric shock or personal injury.
SNever change wiring while power is ON.
Failure to observe this caution may result in electric shock or personal injury.

.
TERMS
−viii −
Basic Terms
Unless otherwise specified, the following definitions are used:
Servomotor: Σ-Series SGMG/SGMD/SGMS/SGM/SGMP servomotor
SERVOPACK: An amplifier (Trademark of Yaskawa servo amplifier “Σ-Series SGDB-jAD
SERVOPACK”)
Servodrive: A servomotor and an amplifier (SGDB SERVOPACK)
Servo system: A complete servo control system consisting of servodrive, host controller,
and peripheral devices
Visual Aids
The following aids are used to indicate certain types of information for easier reference.
Indicates references for additional information.
Technical terms placed in bold in the text are briefly explained in a “TERMS” sec-
tion at the bottom of the page. The following kinds of technical terms are explained:
Technical terms that need to be explained to users who are not very familiar with
servo systems or electronic devices and technical terms specific to ΣSeries Ser-
vos that need to be explained in descriptions of functions.
The text indicated by this icon explains the operating procedure using hand-held
type digital operator (Type: JUSP-OP02A-1).
The text indicated by this icon explains the operating procedure using mount type
digital operator (Type: JUSP-OP03A).
NOTE AΣ-Series Servodrive alone cannot ensure the functionality and performance of the entire
machine control system. It must be combined with an appropriate machine and host control-
ler so that the entire control system works properly. Therefore, carefully read the instruction
manuals for the machine to be used before attempting to operate the servodrive.
JUSP-OP02A-1

−ix −
Yaskawa, 1995
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form, or
by any means, mechanical, electronic, photocopying, recording, or otherwise, without the prior written permission of Yas-
kawa. No patent liability is assumed with respect to the use of the information contained herein.Moreover, becauseYaskawa
is constantly striving to improve its high-quality products, the information contained in this manual is subject to change
without notice. Every precaution has been taken in the preparation of this manual. Nevertheless, Yaskawa assumes no re-
sponsibility for errors or omissions. Neither is any liability assumed for damages resulting from the use of the information
contained in this publication.

1
1
FOR FIRST-TIME USERS OF AC
SERVOS
This chapter is intended for first-time users of AC servos. It describes the ba-
sic configuration of a servo mechanism and basic technical terms relating to
servos.
Users who already have experience in using a servo should also take a look at
this chapter to understand the features of Σ-Series AC Servos.
1.1 Servo Mechanisms 2.......................
1.2 Servo Configuration 5.....................
1.3 Features of Σ-Series Servos 11................
1.3.1 Servomotor Type 11..................................
1.3.2 Control Type of SERVOPACKs 11.......................
1.3.3 How to Use the SGDB SERVOPACKs 12.................
1

FOR FIRST-TIME USERS OF AC SERVOS
2
1.1 Servo Mechanisms
You may be familiar with the following terms:
•Servo
•Servo mechanism
•Servo control system
In fact, these terms are synonymous. They have the following meaning:
A control mechanism that monitors physical quantities such as specified positions.
In short, a servo mechanism is like a servant who does tasks faithfully and quickly according
to his master’s instructions. In fact, “servo” originally derives from the word “servant.”
TERMS Servo mechanism
According to Japanese Industrial Standard (JIS) terminology, a “servo mechanism” is de-
fined as a mechanism that uses the position, direction, or orientation of an object as a pro-
cess variable to control a system to follow any changes in a target value (set point).
More simply, a servo mechanism is a control mechanism that monitors physical quantities
such as specified positions. Feedback control is normally performed by a servo mecha-
nism. (Source: JIS B0181)
1

1.1Servo Mechanisms
3
Servo system could be defined in more detail as a mechanism that:
•Moves at a specified speed and
•Locates an object in a specified position
To develop such a servo system, an automatic control system involving feedback control
must be designed. This automatic control system can be illustrated in the following block dia-
gram:
Configuration of Servo System
Specified position
input
Servo
amplifier
Servo
motor
Controlled
machine
(load)
Machine position
output
Feedback part
Detector
This servo system is an automatic control system that detects the machine position (output
data), feeds back the data to the input side, compares it with the specified position (input
data), and moves the machine by the difference between the compared data.
In other words, the servo system is a system to control the output data to match the
specified input data.
If, for example, the specified position changes, the servo system will reflect the changes.
In the above example, input data is defined as a position, but input data can be any physical
quantities such as orientation (angle), water pressure, or voltage.
Position, speed, force (torque), electric current, and so on are typical controlled values for a
servo system.
The main technical terms used in this manual are as follows:
1) Servo mechanism
2) Servo
Normally, servo is synonymous with servo mechanism. However, because “mechanism” is
omitted, the meaning becomes somewhat ambiguous. Servo may refer to the entire servo
mechanism but may also refer to an integral part of a servo mechanism such as a servomotor
or a servo amplifier. This manual also follows this convention in the use of the term “servo”.
TERMS Feedback control
A control that returns process variables to the input side and forms a closed loop. It is also
called closed-loop control.
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FOR FIRST-TIME USERS OF AC SERVOS
4
3) Servo control system
Servo control system is almost synonymous with servo mechanism but places the focus on
system control. In this manual, the term “servo system” is also used as a synonym of servo
control system.
Related Terms Meaning
Servomotor General servomotors or Yaskawa SGMjservomotors. In
some cases, a position detector (encoder) is included in a
servomotor.
SERVOPACK Trademark of Yaskawa servo amplifier “SGDB
SERVOPACK.”
Servo drive A servomotor and amplifier pair. Also called “servo.”
Servo system A closed control system consisting of a host controller,
servo drive and controlled system to form a servo
mechanism.
Host controller
Reference
Amplifier
(SERVOPACK) Servomotor
Operate
Controlled
system
Servo drive
Servo system
1

1.2 Servo Configuration
5
1.2 Servo Configuration
The following diagram illustrates a servo system in detail:
Position or
speed
reference
Host controller
Servo amplifier
Comparator Power
amplifier
(Input)
Motor
drive
circuit
(Output)
Position
Speed
Gear Movable
table
Position or
speed
feedback
Controlled
system
Ball screw
Detector servomotor Drive system
(1)
(2)
(3)
(4)
(5)
(1) Controlled system: Mechanical system for which the position or speed is to be con-
trolled.
This includes a drive system that transmits torque from a servo-
motor.
(2) Servomotor: A main actuator that moves a controlled system. Two types are
available: AC servomotor and DC servomotor.
(3) Detector: A position or speed detector. Normally, an encoder mounted on
a motor is used as a position detector.
(4) Servo amplifier: An amplifier that processes an error signal to correct the differ-
ence between a reference and feedback data and operates the
servomotor accordingly. A servo amplifier consists of a
comparator, which processes error signals, and a power ampli-
fier, which operates the servomotor.
(5) Host controller: A device that controls a servo amplifier by specifying a position
or speed as a set point.
1

FOR FIRST-TIME USERS OF AC SERVOS
6
Servo components (1) to (5) are outlined below:
(1) Controlled system
In the previous figure, the controlled system is a movable table for which the position
or speed is controlled. The movable table is driven by a ball screw and is connected to
the servomotor via gears.
So, the drive system consists of:
Gears + Ball Screw
This drive system is most commonly used because the power transmission ratio
(gear ratio) can be freely set to ensure high positioning accuracy. However, play in the
gears must be minimized.
The following drive system is also possible when the controlled system is a movable
table:
Coupling + Ball Screw
When the power transmission ratio is 1 :
1, a coupling is useful because it has no
play.
This drive system is widely used for ma-
chining tools.
Timing Belt + Trapezoidal Screw Thread
A timing belt is a coupling device that allows
the power transmission ratio to be set freely
and that has no play.
A trapezoidal screw thread does not provide
excellent positioning accuracy, so can be
treated as a minor coupling device.
To develop an excellent servo system, it is important to select a rigid drive system that
has no play.
Configure the controlled system by using an appropriate drive system for the control
purpose.
TERMS Drive system
Also called a drive mechanism.
A drive system connects an actuator (such as a servomotor) to a controlled system and
serves as a mechanical control component that transmits torque to the controlled system,
orientates the controlled system, and converts motion from rotation to linear motion and
vice versa.
1
Coupling
Rolling-contact
guide
Ball screw Rolling-contact
bearing
Housing
Trapezoidal
screw
thread
Servomotor Timing belt

1.2 Servo Configuration
7
(2) Servomotor
(a) DC servomotor and AC servomotor
Servomotors are divided into two types: DC servomotors and AC servomotors.
DC servomotors are driven by direct current (DC). They have a long history. Up
until the 1980s, the term “servomotor” used to imply a DC servomotor.
From 1984, AC servomotors were emerging as a result of rapid progress in micro-
processor technology. Driven by alternating current (AC), AC servomotors are
now widely used because of the following advantages:
•Easy maintenance: No brush
•High speed: No limitation in rectification rate
Note however that servomotors and SERVOPACKs use some parts that are sub-
ject to mechanical wear or aging. For preventive maintenance, inspect and re-
place parts at regular intervals.
For details, refer to Chapter 6 Inspection, Maintenance, and Troubleshooting.
(b) AC servomotor
AC servomotors are divided into two types: synchronous type and induction type.
The synchronous type is more commonly used.
For a synchronous type servomotor, motor speed is controlled by changing the
frequency of alternating current.
A synchronous type servomotor provides strong holding torque when stopped, so
this type is ideal when precise positioning is required. Use this type for a servo
mechanism for position control.
The following figure illustrates the structure of a synchronous type servomotor:
Light-emitting
element
Rotary disc
Light-receiving
element Armature
wire
Housing
Stator core
Front cap
Ball bearing
Shaft
Rotor core
Magnet
Lead wire
Position detector
(encoder)
Yaskawa SGMjservomotors are of the synchronous type.
1

FOR FIRST-TIME USERS OF AC SERVOS
8
(c) Performance of servomotor
A servomotor must have “instantaneous power” so that it can start as soon as a
start reference is received.
The term “power rating (kW/s)” is used to represent instantaneous power.
It refers to the electric power (kW) that a servomotor generates per second.
The greater the power rating, the more powerful the servomotor.
(3) Detector
A servo system requires a position or speed detector. It uses an encoder mounted on
a servomotor for this purpose.
Encoders are divided into the following two types:
(a) Incremental Encoder
An incremental encoder is a pulse generator, which generates a certain number
of pulses per revolution (e.g., 2,000 pulses per revolution). If this encoder is con-
nected to the mechanical system and one pulse is defined as a certain length
(e.g., 0.001 mm), it can be used as a position detector.
However, this encoder does not detect an absolute position and merely outputs a
pulse train. Zero point return operation must be performed before positioning.
The following figure illustrates the operation principle of a pulse generator:
Phase A pulse train
Phase B pulse train
Slit
Center of
revolution Fixed slit
Light-emitting
element
Light-receiving
element
Rotary
disc
Rotary slit
Phase A
Phase B
Phase Z
(b) Absolute encoder
An absolute encoder is designed to detect an absolute angle of rotation as well as
to perform the general functions of an incremental encoder. With an absolute en-
coder, therefore, it is possible to create a system that does not require zero point
return operation at the beginning of each operation.
•Difference between an absolute and incremental encoder:
An absolute encoder will keep track of the motor shaft position even if system
power is lost and some motion occurs during that period of time. The incremental
encoder is incapable of the above.
1

1.2 Servo Configuration
9
(4) Servo amplifier
A servo amplifier is required to operate an AC servomotor.
The following figure illustrates the configuration of a servo amplifier:
Servo amplifier
Reference
input
Motor driving AC power
Comparator
Power
amplifier
Feedback Servomotor
Commercial AC power
A servo amplifier consists of the following two sections:
(a) Comparator
A comparator consists of a comparison function and a control function. The com-
parison function compares reference input (position or speed) with a feedback
signal and generates a differential signal.
The control function amplifies and transforms the differential signal. In other
words, it performs proportional (P) control or proportional/integral (PI) control.
(It is not important if you do not understand these control terms completely at this
point.)
(b) Power amplifier
A power amplifier runs the servomotor at a speed or torque proportional to the
output of the comparator. In other words, from the commercial power supply of
50/60 Hz, it generates alternating current with a frequency proportional to the ref-
erence speed and runs the servomotor with this current.
TERMS Proportional/integral (PI) control
PI control provides more accurate position or speed control than proportional control, which
is more commonly used.
1

FOR FIRST-TIME USERS OF AC SERVOS
10
(5) Host controller
A host controller controls a servo amplifier by specifying a position or speed as a set
point.
For speed reference, a position control loop may be formed in the host controller when
a position feedback signal is received. Yaskawa MP920 is a typical host controller.
TERMS MP920
A machine controller. If combined with a servo amplifier
for speed control (maximum 44 axes control), the MP920
can provide position control.
The MP920 also provides programmable controller func-
tions.
1

1.3 Features ofΣ-Series Servos
11
1.3 Features of Σ-Series Servos
This section describes the features of Σ-Series servos.
1.3.1 Servomotor Type
Σ-Series SGMjservomotors are synchronous type servomotors and have the following
features:
Rated rotation speed
Maximum rotation speed
Rated output
SGMG 1500 r/min
3000 r/min
0.45 to 15 kW
(10 models)
1000 r/min
2000 r/min
0.3 to 6.0 kW
(8 models)
SGMS 3000 r/min
4500 r/min
1.0 to 5.0 kW
(6 models)
SGMD 2000 r/min
3000 r/min
2.2 to 4.0 kW
(3 models)
SGM 3000 r/min
4500 r/min
0.4 to 0.8 kW
(2 models)
SGMP 3000 r/min
4500 r/min
0.4 to 1.5 kW
(3 models)
1.3.2 Control Type of SERVOPACKs
SGDB model SERVOPACKs allow the control of speed, position and torque.
•Speed control (analog reference)
Accepts an analog voltage speed reference.
•Speed control (contact reference)
There are 3 internally set speeds. One of
these is selected as a reference by a contact.
•Position control (pulse reference)
Accepts a pulse train position reference
•Torque control (analog reference)
Accepts an analog voltage torque reference
1
SGMG type
SGMP type
SGDB SERVOPACK

FOR FIRST-TIME USERS OF AC SERVOS
1.3.3 How to Use the SGDB SERVOPACKs
12
1.3.3 How to Use the SGDB SERVOPACKs
JUsing SERVOPACK for Speed Control
The most common use of a SERVOPACK for speed control is shown below:
Host controller
Position reference +
Speed
reference
Power
amplifier
(Analog
voltage)
Position
Convert
Torque
(current)
feedback
Pulse train
Servomotor
Position feedback Encoder
Position control loop
Position
feedback
Speed
SERVOPACK
(speed control mode)
As shown in the above figure, a position control loop is formed in the host controller. The
host controller compares a position reference with a position feedback signal and sends
the processed result to the SERVOPACK as a speed reference.
In this way the host controller can be freed from performing the servo mechanism control.
The SERVOPACK undertakes the speed control loop and subsequent control proces-
sing.
The Yaskawa programmable machine controller MP920 is used as a typical host control-
ler.
1

1.3 Features ofΣ-Series Servos
13
JUsing SERVOPACK for Torque Control
SERVOPACK for torque control can be used as shown below:
Position
monitoring
Position
information
Host controller
SERVOPACK
(torque control mode)
Power
amplifier
(Analog
voltage) Torque
(current)
feedback
Pulse train
Servomotor
Position feedback Encoder
Torque
reference
The host controller outputs a torque reference to control the SERVOPACK. It also re-
ceives a pulse train (position information) from the SERVOPACK and uses it to monitor
the position.
JUsing SERVOPACK for Position Control
SERVOPACK for position control can be used as shown below:
Position
monitoring
Speed/current loop
Position
information
Host controller
Pulse train
Servomotor
Position feedback Encoder
Pulse
train
Position
reference
Power
amplifier
SERVOPACK
(position control mode)
1