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Mach Discussion => General Mach Discussion => Topic started by: manmeran on July 03, 2010, 02:33:20 PM

Title: SERVO motor
Post by: manmeran on July 03, 2010, 02:33:20 PM
I've decided to build a third CNC machine, but with servo motor.
i have 3 AC servo motor with Specifications :
1-Analog
2-speed control
3-about 400W  1.3N.m 3000 RPM

now i have two questions:

1-my motor are analog, and I can not use them without intermediaries( i mean :converter digital to analog) .i want use "KFLOP" .
  i see in specification  > """ 8 Channels Servo Drive Analog Outputs, Range ±10V """
  I think it is a good choice.
  Whether there is another choice?

2-Considering the fact that these motors are Speed control ,I can use them for router machine ? Whether they are suitable ?

Amir
Title: Re: SERVO motor
Post by: Hood on July 03, 2010, 06:44:27 PM
I am presuming you are meaning the drives (amplifiers) are analogue as servo motors are just motors and dont care what signal the drive gets..
If the drives are analogue only then yes you will need an external device such as K-Flop ( I think you also need the K-Analog board ) or you could also use the DSPMC motion controller. There is also a board that will do the conversion from StepDir to +-10v, its called something like YAPSC but I have no idea whether its any good where as a lot of people are using the K-Flop and DSPMC with Mach and get great results.

Check however that your drives are definitely not capable of Step/Dir as quite a few are capable of different modes, the Allen Bradley ones I use can be set up for various analogue modes and also various position and follower modes, ie Step/Dir.

Hood
Title: Re: SERVO motor
Post by: manmeran on July 04, 2010, 01:50:26 AM
yes ,i mean is drives . my driver is analog and only one mode > Speed control 
this is manual for drivers :
http://registerproduct.yaskawa.com/site/DMServo.nsf/627c1f2261ba3de586256e990062cfce/86256ec30069fdef86256de2005b965a?OpenDocument (http://registerproduct.yaskawa.com/site/DMServo.nsf/627c1f2261ba3de586256e990062cfce/86256ec30069fdef86256de2005b965a?OpenDocument)

Title: Re: SERVO motor
Post by: manmeran on July 04, 2010, 05:16:10 AM
what are different between "position control" and "speed control"  in cnc machine? or torque control ?


Amir
Title: Re: SERVO motor
Post by: manmeran on August 22, 2010, 01:55:02 AM
i have a big problem with analog servo system .
in digital driver, when pin S-ON is active, and dont have any pulse in input, we see that shaft motor is Motionless and LOCK(if we want turn shaft with hand , we dont can)
but in analog drive, when i set 0V for input ,motor is motionless BUT i can turn shaft motor with hand.
why?

Amir
Title: Re: SERVO motor
Post by: manmeran on August 25, 2010, 03:39:34 AM
No one has experience with analog ِDriver ?
Title: Re: SERVO motor
Post by: Jeff_Birt on September 04, 2010, 01:47:43 PM
Hi Amir,

Here is a good thread on CNCZone that explains the different types of servo control: http://www.cnczone.com/forums/showthread.php?t=66964

Your motors/drivers will likely work fine but you will need a controller that can convert S/D signals to analog. I have used a Galil card for this purpose, but KFlop and others also may work.
Title: Re: SERVO motor
Post by: manmeran on September 04, 2010, 01:52:08 PM
thx jeff
but this issue:
Quote
in analog drive, when i set 0V for input ,motor is motionless BUT i can turn shaft motor with hand.

Amir
Title: Re: SERVO motor
Post by: Jeff_Birt on September 04, 2010, 02:22:38 PM
This could be because you don't have the drive enabled, the drive is not seeing proper feedback from the encoder and shuts down, etc. Any LED indicators on your drive?
Title: Re: SERVO motor
Post by: manmeran on September 04, 2010, 02:41:08 PM
jeff, i set enable pin with +24V and i can turn motor with for example 2volt,and all thing is ok.
no alarm there is in driver.
problem is when i change 2volt to 0V ,motor is motionless but not lock(turn with hand) ,While the lock should be(Exactly like Digital servo system OR like step motor).

Amir
Title: Re: SERVO motor
Post by: Jeff_Birt on September 04, 2010, 02:57:04 PM
So if you apply +2V it rotates one direction, -2V it rotates the other direction, but only at 0V there is no power applied to motor? Does your driver have a 'coast' mode or something?
Title: Re: SERVO motor
Post by: manmeran on September 04, 2010, 03:04:07 PM
Quote
at 0V there is no power applied to motor?
there is BUT very little. The amount I can movements with hand of motor shaft .

Quote
'coast' mode
I do not know
?