Mitsubishi Electric MELSEC FX Series User manual

INDUSTRIAL AUTOMATION
MITSUBISHI ELECTRIC
MITSUBISHI ELECTRIC
MELSEC FX Series
Programmable Logic Controllers
Introduction to
FX Positioning Control Systems
Beginners Manual
Art. no.: 214562
21 03 2014
Version C Version check

Beginners Manual
Introduction to MELSEC FX Positioning Control Systems
Art. no: 214562
Version Revisions / Additions / Corrections
A 05/2008 pdp - rw First edition
B 08/2012 pdp - dk Addition of FX3G main units
C 03/2014 pdp - dk Addition of FX3GC, FX3GE and FX3S main units

About This Manual
The texts, illustration, diagrams and examples in this manual are provided
for information purposes only. They are intended as aids to help explain the
operation, programming and use of programmable controllers of the programmable
logic controllers of the MELSEC FX
1S , FX 1N , FX 2N, FX 2NC , FX 3G , FX 3GC , FX 3GE , FX 3S , FX 3U and FX 3UC series.
If you have any questions about the installation and operation of any of the
products described in this manual please contact your local sales office or distributor (see back cover).
You can find the latest information and answers to frequently asked questions on our website at
https://eu3a.mitsubishielectric.com.
MITSUBISHI ELECTRIC EUROPE BV reserves the right to make changes
to this manual or the technical specifications of its products at any time without notice.
©05/2008
MITSUBISHI ELECTRIC EUROPE B.V.

FX Positioning Control Systems I
Safety Guidelines
General safety information and precautions
For use by qualified staff only
This manual is only intended for use by properly trained and qualified electrical technicians who are
fully acquainted with the relevant automation technology safety standards. All work with the
hardware described, including system design, installation, configuration, maintenance, service and
testing of the equipment, may only be performed by trained electrical technicians with approved
qualifications who are fully acquainted with all the applicable automation technology safety
standards and regulations. Any operations or modifications to the hardware and/or software of our
products not specifically described in this manual may only be performed by authorised Mitsubishi
Electric staff.
Proper use of the products
The programmable logic controllers of the FX 1S , FX 1N , FX 2N, FX 2NC , FX 3G , FX 3GC , FX 3GE , FX 3S , FX 3U and
FX
3UC series are only intended for the specific applications explicitly described in this manual. All
parameters and settings specified in this manual must be observed. The products described have all
been designed, manufactured, tested and documented in strict compliance with the relevant safety
standards. Unqualified modification of the hardware or software or failure to observe the warnings on
the products and in this manual may result in serious personal injury and/or damage to property. Only
peripherals and expansion equipment specifically recommended and approved by Mitsubishi
Electric may be used with the programmable logic controllers of the MELSEC FX family.
All and any other uses or application of the products shall be deemed to be improper.
Relevant safety regulations
All safety and accident prevention regulations relevant to your specific application must be observed
in the system design, installation, configuration, maintenance, servicing and testing of these
products. The regulations listed below are particularly important in this regard. This list does not claim
to be complete, however; you are responsible for being familiar with and conforming to the
regulations applicable to you in your location.
●VDE Standards
– VDE 0100
Regulations for the erection of power installations with rated voltages below 1000 V
– VDE 0105
Operation of power installations
– VDE 0113
Electrical installations with electronic equipment
– VDE 0160
Electronic equipment for use in power installations
– VDE 0550/0551
Regulations for transformers
– VDE 0700
Safety of electrical appliances for household use and similar applications
– VDE 0860
Safety regulations for mains-powered electronic appliances and their accessories for house-
hold use and similar applications.

II
MITSUBISHI ELECTRIC
●Fire safety regulations
●Accident prevention regulations
–VBGNr.4
Electrical systems and equipment
Safety warnings in this manual
In this manual warnings that are relevant for safety are identified as follows:
m
DANGER:
Failure to observe the safety warnings identified with this symbol can result in health and injury
hazards for the user.
b
WARNING:
Failure to observe the safety warnings identified with this symbol can result in damage to the
equipment or other property.

FX Positioning Control Systems III
General safety information and precautions
The following safety precautions are intended as a general guideline for using PLC systems together
with other equipment. These precautions must always be observed in the design, installation and
operation of all control systems.
m
DANGER:
●Observe all safety and accident prevention regulations applicable to your specific applica-
tion. Always disconnect all power supplies before performing installation and wiring work
or opening any of the assemblies, components and devices.
●Assemblies, components and devices must always be installed in a shockproof housing fitted
with a proper cover and fuses or circuit breakers.
●Devices with a permanent connection to the mains power supply must be integrated in the
building installations with an all-pole disconnection switch and a suitable fuse.
●Check power cables and lines connected to the equipment regularly for breaks and insulation
damage. If cable damage is found immediately disconnect the equipment and the cables
from the power supply and replace the defective cabling.
●Before using the equipment for the first time check that the power supply rating matches that
of the local mains power.
●Take appropriate steps to ensure that cable damage or core breaks in the signal lines cannot
cause undefined states in the equipment.
●You are responsible for taking the necessary precautions to ensure that programs inter-
rupted by brownouts and power failures can be restarted properly and safely. In particular,
you must ensure that dangerous conditions cannot occur under any circumstances, even for
brief periods.
●EMERGENCY OFF facilities conforming to EN 60204/IEC 204 and VDE 0113 must remain fully
operative at all times and in all PLC operating modes. The EMERGENCY OFF facility reset
function must be designed so that it cannot ever cause an uncontrolled or undefined restart.
●You must implement both hardware and software safety precautions to prevent the possibil-
ity of undefined control system states caused by signal line cable or core breaks.
●When using modules always ensure that all electrical and mechanical specifications and
requirements are observed exactly.

IV
MITSUBISHI ELECTRIC

Table of Contents
FX Positioning Control Systems V
Table of Contents
Safety Guidelines
1 The Basics of Positioning Control
1.1 What is positioning control? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
1.2 Actuators for positioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.2.1 Pneumatic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.2.2 Brake motor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
1.2.3 Clutch brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1.2.4 Stepping motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
1.2.5 DC servo system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1.2.6 General purpose inverter and general purpose motor . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
1.2.7 AC servo system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5
1.3 Positioning method type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
1.3.1 Speed control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
1.3.2 Position control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
2 Positioning by AC Servo System
2.1 Advantages for using an AC servo system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
2.2 Examples of AC servo systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.2.1 Constant feed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.2.2 Tapping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
2.2.3 Drilling in steel sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
2.2.4 Index table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
2.2.5 Lifter moving-up/down. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.2.6 Cart travel control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
2.2.7 Carrier robot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
3 Components of Positioning Control and their Roles
3.1 Positioning controller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3.1.1 Command pulse control method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
3.1.2 Basic parameter settings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
3.1.3 Zero point return function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
3.2 Servo Amplifier and Servo Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
3.2.1 Positioning control in accordance with command pulse . . . . . . . . . . . . . . . . . . . . . . . . 3-8
3.2.2 Deviation counter function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
3.2.3 Servo lock function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
3.2.4 Regenerative brake function. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9
3.2.5 Dynamic brake function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-10
3.3 Drive mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
3.3.1 Concept of drive system movement quantity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
3.3.2 Setting the target position. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

Table of Contents
FX Positioning Control Systems VI
4 Learning to Use the FX Family for Positioning Control
4.1 MELSEC FX PLC positioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.1.1 Overview of control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
4.1.2 Important memory locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
4.1.3 Program Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
4.2 Inverter Drive Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-21
4.2.1 Overview of control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-21
4.2.2 Using the MELSEC FX and FREQROL Inverter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-22
4.2.3 Program example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-27
4.3 FX2N-1PG-E positioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-37
4.3.1 Overview of control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-37
4.3.2 Important buffer memory locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-38
4.3.3 Program example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-39
4.4 FX2N-10PG positioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-44
4.4.1 Overview of control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-44
4.4.2 Important buffer memory locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-45
4.4.3 Program example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-46
4.5 FX2N-10GM and FX2N-20GM positioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-52
4.5.1 Overview of control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-52
4.5.2 Using dedicated software to set positioning for the FX2N-20GM . . . . . . . . . . . . . . .4-53
4.5.3 Testing and monitoring operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-59
4.6 FX3U-20SSC-H positioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-61
4.6.1 Overview of control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-61
4.6.2 Using dedicated software to set positioning for the FX3U-20SSC-H. . . . . . . . . . . . . 4-62
4.6.3 Testing and monitoring operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-65
4.6.4 Important buffer memory locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4-66
4.6.5 Program example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-67
Index

What is positioning control? The Basics of Positioning Control
FX Positioning Control Systems 1 - 1
1 The Basics of Positioning Control
1.1 What is positioning control?
The positioning controller, together with the programmable logic controller, personal computer and
operator interface, is one of the four main units of FA (factory automation).
Among these units, the positioning controller plays an important role and is regarded as the center of
the mechatronics field in which many senior engineers have been playing active roles.
Positioning is all about motion, and motion often involves speed and precision. And since speed can
be directly related to productivity, positioning is an area of much development. When the speed of a
machine increases, a problem with the stop precision is often generated. In order to solve this
problem, diversified grades of positioning controllers have been required and developed.
Improving machine efficiency generates immeasurable added value, including reduced labor costs
and improved conservation of machine floor space for the same quantity of production. If there are no
problems related to the positioning aspect of a machine, it may mean that the machine is not running
as efficiently as it could be. This is where the science of developing and retrofitting an optimum
positioning control system comes in.

The Basics of Positioning Control Actuators for positioning
1 - 2
MITSUBISHI ELECTRIC
1.2 Actuators for positioning
The options available for positioning control depend on the type of actuator driving the system. An
actuator is a mechanical device that moves or controls a specific element or a series of elements within
a system.
In a mechanical system, an actuator is often used with a sensor to detect the motion or position of a
workpiece. The following illustrations provide examples of diversified actuators, their features and
their weak points.
1.2.1 Pneumatic
Features and Drawbacks
●Air source and high grade piping are required.
●High torque is not available.
●Multi-point positioning is complex and very difficult to achieve.
●Change in positioning is difficult.
1.2.2 Brake motor
Features and Drawbacks
●Positioning mechanism is simple.
●Repeatability is poor.
●Change in positioning is difficult.
(When optical sensors or limit switches are used for stop)
Fig. 1-1: Schematic drawing
Pneumatic
120010da.eps
Fig. 1-2: Schematic drawing
Brake motor
120020da.eps
Air cylinder
Workpiece
Compressor
Piping
Limit switch
Motor with brake

Actuators for positioning The Basics of Positioning Control
FX Positioning Control Systems 1 - 3
1.2.3 Clutch brake
Features and Drawbacks
●Frequent positioning is possible.
●Life of friction plate is limited.
●Change in positioning is difficult.
(When optical sensors or limit switches are used for stop)
1.2.4 Stepping motor
Features and Drawbacks
●Simple positioning mechanism.
●If load is heavy, motor may step out and displacement can occur.
●Motor capacity is small.
●Precision is poor at high speed.
Fig. 1-3: Schematic drawing
Clutch Brake
120030da.eps
Fig. 1-4: Schematic drawing
Stepping motor
120040da.eps
Motor
Clutch brake
unit
Speed reducer
Optical
sensor
Constant
quantity
feed hopper
Stepping
motor
Controller

The Basics of Positioning Control Actuators for positioning
1 - 4
MITSUBISHI ELECTRIC
1.2.5 DC servo system
Features and Drawbacks
●Positioning precision is accurate.
●Maintenance is required for motor brushes.
●It is not suitable for rotation at high speed.
1.2.6 General purpose inverter and general purpose motor
Features and Drawbacks
●Multi-speed positioning is available using a high-speed counter.
●High precision positioning is not available.
●Large torque is not available at start.
(Specialized inverter is required)
Fig. 1-5: Schematic drawing
DC servo system
120050da.eps
Fig. 1-6: Schematic drawing
General purpose inverter and
general purpose motor
120060da.eps
DC servomotor
DC servo amplifier
Lifter
Motor with brake
General-purpose
inverter

Actuators for positioning The Basics of Positioning Control
FX Positioning Control Systems 1 - 5
1.2.7 AC servo system
Features and Drawbacks
●Positioning precision is good.
●Maintenance is not required.
●Positioning address can be easily changed.
●It is compact, and offers high power.
Fig. 1-7: Schematic drawing
AC servo system
120030da.eps
AC servo amplifier
Sheet material
AC servo
motor
Cutter

The Basics of Positioning Control Positioning method type
1 - 6
MITSUBISHI ELECTRIC
1.3 Positioning method type
In general, there are two methods to control the movement of a workpiece: speed control and
position control. For basic, more rudimentary positioning, speed control can be used with an inverter
and general purpose motor. For systems where precision is a must, servo systems are required for the
advanced handling of pulse commands.
1.3.1 Speed control
Limit switch method
Two limit switches are provided in places where a system’s moving part passes. At the first limit switch,
the motor speed is reduced. At the second limit switch, the motor turns off and the brake turns on to
stop the moving part.
In this method, because position controllers are not required, the system configuration can be
realized at reasonable cost.
– Guideline of stopping precision: Approximately ±1.0 to 5.0 mm
(The stop precision shows a value in a case where the low speed is 10 to 100 mm/s.)
120080da.eps
Fig. 1-8: Schematic drawing – Limit switch method
BIM
INV
Moving part
Ball screw
Limit switch for
changeover to
low speed
Limit switch for
stop
0 to 10 V DC
Inverter
Brake
Inductive motor
High speed
Low speed
Movement distance

Positioning method type The Basics of Positioning Control
FX Positioning Control Systems 1 - 7
Pulse count method
A position detector (such as a pulse encoder) is set up in a motor or rotation axis. The pulse number
generated from the position detector is counted by a high-speed counter. When the pulse number
reaches the preset value, the moving part stops.
In this method, because limit switches are not used, the stop position can be easily changed.
– Guideline of stopping precision: Approximately ±0.1 to 0.5 mm
(The stop precision shows a value in a case where the low speed is 10 to 100 mm/s.)
In speed control applications with inverters, stop precision is not very accurate. With the limit switch
method, a system operates without any feedback to the controller to indicate the location of the
workpiece. With the pulse count method, the speed can be changed and the stop command can be
executed at specific distances (at specific timings) according to the feedback from the pulse
generator connected to the motor. Both the limit switch method and the pulse count method,
however, are subject to a loss in stop precision due to the dispersion of distance that occurs for
workpieces at different speeds.
●When automatically stopping a moving part driven by a motor, stop the motor by a position signal
(using a limit switch or pulse count comparison). In general conditions, turn on the brake at the
same time.
120090da.eps
Fig. 1-9: Schematic drawing – Pulse count method
PLG IM
INV
Moving part
Ball screw
DC 0 to
10 V
Inverter
Pulse generator
Inductive motor
High speed
Low speed
Pulses are fed
back
PLC
Programmable
controller
High speed
counter unit Movement distance

The Basics of Positioning Control Positioning method type
1 - 8
MITSUBISHI ELECTRIC
●The moving part continues by a coasting distance until it completely stops, after the stop
command is given. The coasting distance is not controlled and it is represented as the shaded
part in the figure below.
●Dispersion in the stop distance changes as shown below. Dispersion is affected by the speed of
the workpiece when the stop command is given and the speed reduction time delay after stop.
●If the required stop precision is not satisfactory when stopping from the normal operation speed,
the most effective method to improve the stop precision is to reduce the operation speed.
However, if the operation speed is simply reduced, the machine efficiency may also be reduced.
Therefore, in actual operation, the motor speed can be reduced from a high speed to a low speed
before the motor is stopped, as shown below.
Fig. 1-10: Positioning pattern
1200b0da.eps
Fig. 1-11: Positioning pattern
1200c0da.eps
1200d0da.eps
Fig. 1-12: Positioning pattern
Speed
Time
StopStop command
Coasting
distance
Speed
Time
Stop
Stop
command
Dispersion in
stop
Stop
Speed recuction start
Time delay
Speed
Time
Stop
Speed reduction
command
Improved stop
precision
Stop command
Low
speed
Speed
Time delay
Poor stop
precision
Stop
command Stop
Time
High speed High speed