On Fri, 14 Mar 2008, Howard Chan wrote:
Date: Fri, 14 Mar 2008 00:06:03 +0800
From: Howard Chan <[EMAIL PROTECTED]>
Reply-To: "Enhanced Machine Controller (EMC)"
<emc-users@lists.sourceforge.net>
To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net>
Subject: Re: [Emc-users] Can EMC2 support any 'AC Servo Motor'?
Dear All,
I am very happy, you propose some practical suggestions. I and my
members take a meeting and decide that we will buy 5I20 control card and
7I33 analog servo amp interface. But there are problems, I would like
to ask. Rayh said that EMC2 and Sanyo servo amp support step and
direction. I try to find this method in the Sanyo manual and HAL
handbook but I am not sure is it correct.
The Sanyo amplifier also supports Analog velocity input (+-10V)
This is the input you would use with the 5I20/7I33T
In page 45(3-13) of the Sanyo manual, it tells me that there are three
types of command input pulse, Positive + Reverse pulse, Code + pulse
train and 90 deg phase difference. In page 123(7-10), it shows me more
detail information about them. I think that is it only ??Code + pulse
train?? can be supported in the EMC2. If I want to use it type, should I
buy 5I20 and 7I37 (Isolated Anything ?? IO adapter)?
You would be better of using the analog velocity input with EMC2
In the 7I37 manual, MOSFET outputs turn on in 2 uSec and off in 5 uSec
but in the Sanyo manual page 123(7-10), the response time need at least
or equal to 0.1 uSec. It means that 7I37 is not suitable this servo amp?
The 7I37 is intended for power switching (relays solenoids etc) Normally for
step and direction you can use the 5I20 outputs directly, or through a
breakout board (7I42) These are not isolated but normally the step/direction
inputs on the amplifier are isolated so isolation at the PC is not needed.
But, for EMC2 I think you are better off with using the +-10V velocity inputs
of the amplifiers, rather than step/direction.
At last, according to their experience to create the machine
and > configure the EMC2, would you mind giving me some hits which thing we
should be take care. Thank you very much.
Best regards,
Howard
Hi Howard
Glad to hear of your interest in EMC2. It is a great system for students
because it will allow you to experiment with most motion control variables.
The pdf at the link you posted includes a lot of sales pitch. It appears to
have been written and edited by someone with limited motion control experience.
They have very successfully blended together at least three input signal types
to maximize the apparent value of their products. You will need to sort out
most all of it to get the system that will work for you.
Sanyo lists three kinds of motion signals. They include analog voltage, step
and direction, and CANopen. EMC2 as it exists right now can handle two of
these, analog voltage, and step and direction. We do NOT have serial drivers
in our motion software that would permit CANopen control. Hint -- Serial
communication using CANopen would be an excellent graduate student project.
I'll expand just a bit on the two systems we do have for your use right now.
It looks like Step and Direction signals can be used with both the stand alone
amps and with the multi axis package. EMC2 produces millions of step and
direction signals every day. They are the preferred motion signal for stepper
motor powered systems. What this drive does is make the servo motor look like
a stepper motor if you use this control signal. You will have a real advantage
over steppers because the motor's torque will not fall off as speed increases
but you will still see some cogging at low speeds. There may also be an upper
RPM limit, well below the max speed of the motors unless the drive includes a
pulse multiplier or you add an external hardware work around.
Permit me to do a bit of computation on this max rotational velocity using step
signals. If the supplied encoder is 2500 pulses per rev, and the amp equates
external steps one-to-one then you will need 2500 pulses for each revolution.
Let's imagine that your computer can supply 30k pulses per second (PPS) using
the EMC2. That combination will allow 12 revolutions per second or 720 RPM.
What is the maximum pulse speed you can expect from EMC2. Alex and I were is a
bit of a contest a while back and were able to get pulse speeds of 75 to 90
thousand pulses per second. It may be that we could get even faster speeds now
that Jeff has added his rate doubler. You can see that rotational speed is
still somewhat limited. At 90k PPS you would be limited to about 2100 RPM.
The second type of speed signal that EMC2 can offer is an analog signal. This
could be pulse width or -10 tp +10 volt using a PC card like Alex and Tom
suggested. These analog signals have the advantage of driving the motor to
full speed and to constant velocity at low speeds. Analog has the advantage of
producing a real, closed loop servo system. I would use this system even
though it costs the price of an extra computer board and requires a bit more
care in wiring. If you choose analog signals you must make certain the amps
you purchase allow you to connect those signals. Not all of the amps listed do
that.
It looks like, although the pdf does not say so, that you will need to use a
Microsoft OS to tune the amps. Writing a Linux/EMC2 based tuning software for
these drives would also be a valuable student project, if your school and
discipline includes both hardware and code writing.
Good luck and welcome.
Rayh
--- [EMAIL PROTECTED] wrote:
From: "Alex Joni" <[EMAIL PROTECTED]>
To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net>
Subject: Re: [Emc-users] Can EMC2 support any 'AC Servo Motor'?
Date: Wed, 12 Mar 2008 13:57:00 +0200
Hello,
for what you want to accomplish you need a special motion control board.
A list with supported hardware by emc2 can be found at:
http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?EMC2_Supported_Hardware
Best regards,
Alex
----- Original Message -----
From: WF Chan
To: emc-users@lists.sourceforge.net
Sent: Wednesday, March 12, 2008 1:15 PM
Subject: [Emc-users] Can EMC2 support any 'AC Servo Motor'?
Dear All,
I am a student. I will use a open platform system to control three axis AC
Servo motors in my final year project(FYP). I searched a EMC2 in the
internet. It is base of the linux OS, it supports maximum 9 axis (very
powerful), GM code and graphics mode. It is very suitable for me to do my
FYP.
I have questions to ask all people:
1. I must use AC Servo motors to do my project and I choose SANMOTION R of
SANYO DENKI INC. Below is the user manual:
http://www.sanyo-denki.com/Data/Servo/catalogs/R_Ver3.pdf
In page 42(3-10), the pin 21 is the input control command which is using
speed and torque value.
But I found in the HAL Handbook that it only support ??step pulse?? to do
the control.
Is it menu that the EMC2 cannot support any AC servo motors??
Are there any people can help me or give me any suggestions how to solve my
problem?
Thank you very much!!
Best regards,
Howard
Yahoo! ??????????????????????????????! ????????
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Mesa Electronics
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