Yaskawa
eLearning
[Music playing]
The Technical Training Department of Yaskawa America Incorporated presents
Features and Benefits of the Sigma-7 Servo System
Hi, I'm Steve Koehler here to provide an overview of Yaskawa's Sigma-7,
the servo system for the next revolution.
Sigma-7 delivers exceptionally high speed and extraordinarily accurate
control which maximizes system performance.
Simply put, it allows you to operate your machinery faster and with higher
precision than ever before.
During this presentation, we're going to look at how Sigma-7's advancement in
technology deliver all of the performance improvements listed here,
while making it easier to use
And to top it all off, you'll see that Sigma-7 delivers those enhancements
without sacrificing quality and reliability
Simply put, these improvements mean you get more out of your machine.
So let's take a closer look at the improvements,
starting with faster response time.
Velocity loop bandwidth has been increased to 3.1 kHz.
Now, that's not a number you need to memorize as long as you remember that it
leads to a number of important benefits.
Increased velocity loop bandwidth means you get much more rapid position
settling time.
This is especially significant for high-performance mechanisms that must
make rapid and precise movements from one position to another.
Sigma-7 allows faster response times than ever before which translates
to higher throughput.
Another performance enhancement is tuning-less operation.
No servo tuning is required for load to motor inertia ratios up to 30:1.
Systems can run without vibration and remain stable even when the load inertia
dramatically changes.
As a result, you can decrease motor sizes without sacrificing performance.
Another impressive benefit of Sigma-7 is higher precision movements.
This is made possible because of encoder resolution which has been increased to
more than 16 million pulses per revolution.
Which is 16 times higher than those of previous generation Sigma-V servo motors.
Even though you may not need such a high resolution for positioning accuracy
higher encoder resolution improves path following and accuracy.
And each servo can get to the end position faster
Think of it like the cruise control on a car.
When you dial in a certain speed there may be a slight fluctuation as the
system works to maintain that speed.
How smoothly the car maintains that desired speed depends on how much information is being collected.
Because of the higher resolution encoder more data is collected and processed by
the amplifier to improve speed control and accuracy of motion.
This is an important benefit for just about every application.
For example, this plasma cutting application is able to cut steel with
smooth precise curves.
An additional benefit of higher encoder resolution is that energy efficiency is increased.
Minuscule motor movements can be used to cancel vibrations before they occur.
Thus, using less current to perform the same move.
Next let's talk about vibration suppression.
Yaskawa's filtering functions use speed and torque signals
to identify frequencies that
cause vibration, or resonance, as the motor moves.
A control circuit applies a torque waveform to suppress the vibration.
Vibration can occur at a number of different frequencies.
Here's one way to think about vibration filtering.
Let's say you have a defective car tire that makes noise at 30 miles per hour
but it doesn't make that noise at 20 or 40 miles per hour.
As you accelerate from 20 up to 30 the noise gets worse and then decreases as
you approach 40.
In a similar way the notch filter function filters out vibrations at
certain speeds or frequencies.
There are now five available filters to take out resonance in the high frequency range.
Compared to the previous two filters.
These notch filters allow more high frequencies to be filtered out so they
don't cause noise in the system and as a result system gain and performance can
be increased.
And in the medium frequency range there is now a new parameter that dampens other
resonant frequencies which may be revealed after filtering the main
resonant frequency.
This means that if a machine experiences resonance simply because of the way it
was designed and manufactured the additional filtering capabilities of
Sigma-7 give you more ways to suppress that vibration.
These functions can be adjusted automatically using advanced or custom
auto-tuning.
The user can also manually tune out vibration by adjusting parameters
such as gain compensation, damping gain, and filter time constants.
Now let's take a look at a new function that Sigma-7 provides,
Velocity Ripple Compensation.
With this function Sigma-7 can reduce the speed ripple caused by motor cogging.
This ensures smooth operation and improved performance even in low speed
applications
Ripple compensation is especially useful in applications where smoothness of
motion is critical,
such as coating and laminating.
Smooth motion is also critical when a servomotor is used to inspect a component.
Should the scanning velocity deviate the deviation could be interpreted as a flaw
in the scanned object.
Another significant feature for Sigma-7 is the improved Friction Compensation functionality
The Friction Compensation model compensates for Coulomb friction which
is friction between to dry surfaces,
viscosity friction between a dry and wet surface,
and other external forces such as gravity or forces due to a machining process.
The result is smooth starts and smooth transitions.
Next, let's look at the refined hardware of Sigma-7 starting with the motors.
The first thing you'll notice about a Sigma-7 motor is that they're smaller.
Up to 20% shorter yet they maintain the same shaft size and
mounting dimensions as Sigma-V.
Yaskawa Engineers have developed highly efficient windings for the Sigma-7
and this improves motor efficiency and reduces heat generation compared with
previous models.
Environmental protection ratings have been upgraded for Sigma-7 as well.
These motors are IP67 rated which means they are protected against ingress of
dust particles and have a higher level of water resistance than
the Sigma-V servo motors.
The IP67 rating allows Sigma-7 motors to withstand harsh environments
for a longer duration.
With the reduction and motor length up to 20% and all motors rated IP67,
you'll be hard-pressed to find an application that Yaskawa's Sigma-7
won't fit into.
An outstanding addition
of the Sigma-7 lineup is the small capacity, two-axis amplifier.
That's two amplifiers in one box that share a common input power circuit.
The two axis amplifier has a smaller footprint size than two separate
single-axis amplifiers.
It also reduces wiring cost and complexity by combining input power for
both axes
If for example, you have a winding application where one motor keeps tension
on a spool of material and the other motor feeds the material onto the line,
you have a good application for a small capacity two axis amplifier.
This allows the constant regen power of the tension axis to be reused by the
feed axis without the complication of external power supplies or regen units.
With Sigma-7's modernized communications you can construct a system that
precisely meets your requirements
Communication to the motion controller is achieved through Mechatrolink III or
EtherCAT protocols.
Standard industrial ethernet cables are used for inter connection between nodes.
The Mechatrolink III network communication is a deterministic system
which is vital when working with motion-control.
Mechatrolink III protects against electrical noise due to its data retry functionality.
If data is corrupt or missing it's automatically re-transmitted
within the same transmission cycle.
As a result, you get significantly better performance in electrically noisy environments,
like those typically found in industrial plants and facilities.
Throughout the service life of Sigma-7 products, maintenance has been improved
and simplified.
For preventive maintenance built-in service life monitoring automatically
calculates the remaining service life of amplifier components,
including cooling fans, main circuit capacitors,
in-rush relays, dynamic brake relays,
and other components.
Servo amplifier and servo motor temperatures are constantly monitored
and this data can be monitored by the motion controller over Mechatrolink or EtherCAT.
Now when an alarm occurs, the Alarm Trace function in the servo amplifier
saves a graph of the motion and I/O signals that occurred at the time of the alarm.
This data can be used to troubleshoot and correct the cause of the alarm
Sigma-7 provides smooth integration of mandatory legal safety standards.
For high levels of functional safety Sigma-7 servo amplifiers are
equipped with a Safe Torque Off safety circuit that is fully compliant with the
SIL3 rating of IEC 61508.
This equates to a lower probability of dangerous faults and to increased
reliability as well.
In other words, Sigma-7 lets you build safer machines.
To make the transition to Sigma-7 effortless, Yaskawa has optimized Sigma-7
compatibility with Sigma-V.
Making it easy to improve the performance of your system
by replacing your Sigma-V servo pack with Sigma-7.
Sigma-7 servo amplifiers offer complete installation interchangeability
with models having the same capacity because they share the same mounting footprint.
Additionally, the mounting hole shape is improved,
making it much easier to insert a screwdriver.
To reduce replacement costs Sigma-V cables and connectors can be used to
connect Sigma-7 amplifiers and motors.
And just like Sigma-V, Sigma-7 safety functions
SS1, SS2, and SLS are integrated by using the optional safety card.
With more than nine million servo systems installed,
Yaskawa is known for outstanding reliability.
Today, Sigma-7 delivers even higher levels of reliability
for your production operations
And that translates to reduced service and maintenance costs and less downtime.
So now you've seen an overview of Sigma-7,
here are three questions to help you review.
Question number one:
What types of applications benefit from ripple compensation?
Here are a few choices if you need a hint.
If you're thinking lamination
or part inspection then you are correct.
Ripple compensation is especially useful in applications where smoothness of
motion is critical,
such as lamination or when the servo motor is used to inspect a component.
Question number two:
What is the IP rating for Sigma-7 servo motors?
If you chose IP67, you are correct.
The IP67 rating allows Sigma-7 motors to withstand
harsher environments for longer duration
And our final question:
Can Sigma-V cables be used to retrofit Sigma-7?
The answer is yes.
To reduce replacement costs, Sigma-V cables and connectors can be used to connect
Sigma-7 amplifiers and motors.
Sigma-7 is the new benchmark for servo systems.
It delivers maximum throughput, improved product quality, shorter initial setup time,
and overall lower life cycle cost.
And best of all,
it's from Yaskawa
and that means a high standard of product excellence,
high mean time between failures, low cost of ownership,
quick response to your questions,
free technical support 24/7, and a great return on your investment.
You get it all from Yaskawa, the world's largest manufacturer of AC
drives and motion control products.
At Yaskawa, we do everything we can to make each experience with us a great one.
And you know why?
Because to us, It's Personal!
To learn more about Sigma-7, visit yaskawa.com.