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Galil vs Vital
« on: November 02, 2019, 07:26:58 AM »
I have a mill with DC PM motors with tachos and linear glass slides.  The velocity loop is closed between motors and drive amplifiers which take the usual +/- 10 V velocity signals.  The position loop needs to be closed in the controller.
Currently I am running a Galil 2143 card and mach3, but I want to change to Mach4.  To take full advantage of the capabilities I need to change to a Galil 4143 or 4040 card, which is not cheap.

I have just been made aware ot the Vital Systems options, so I am looking for feedback on both options Galil or Vital?  Or suggestions as to other compatible controllers.
Re: Galil vs Vital
« Reply #1 on: November 03, 2019, 02:44:42 PM »
Hi,
just as a matter of interest what would it cost to replace the existing servos with modern AC servos?

I have recently bought three Delta 750W B2 series (17 bit incremental encoder) for approx $500 each. They are superb.
I suspect they would be cheaper than a new Galill......

Craig
My wife left with my best friend...
     and I miss him!
Re: Galil vs Vital
« Reply #2 on: November 03, 2019, 03:14:37 PM »
Don't those still need +/- 10v to control them?
Re: Galil vs Vital
« Reply #3 on: November 03, 2019, 07:00:04 PM »
Hi,
modern AC servos are (programably) multi-mode. So, yes,  you could use analogue (+/- 10V) control them,either speed or torque modes
but also you can use position mode using the built in encoder.

I suspect if you were to retrofit that position mode is the one you would consider. Note that it renders the glass linear scales redundant.
That may be an issue to you in that linear scales 'enclose' backlash within the feedback loop whereas the rotational encoders on a AC
servo do not. If your ballscrews have no backlash then there is no real difference between the two. If there is backlash then the scales
enclosed in the loop are probably a feature that you would not want to miss on.

Note that you could use the linear scales with AC servos but it would still require an analogue capable controller and any savings you
hoped to make vanish. For instance even, the cheaper of your two options, the Hicon with the required analogue activations is $1200 whereas
a step/direction motion controller like an Ethernet SmoothStepper is $180. Thus the cost saving would pay for two Delta 750W B2 series servos AND drives.
It makes no sense to buy new servos only to then have to use an expensive controller.

The current trend in servos, and has been for twenty plus years, is ever smarter servo drives. In  the early days servo amps were just that 'amplifiers'.
In the very earliest of days there was no tacho feedback.....then came tacho feedback, the came step/direction control with the servo mounted encoders
being monitored by the drive and closing the loop. Gecko 320's are an example of these, brushed DC motors but with the feedback loop completed
by the drive NOT the motion controller. Nowadays with field oriented control has given rise to brushless servos.

More recently still with Ethercat, Profibus, CANOpen and the likes the servo drive assumes responsibility for the motion control of its own servo, this
is called 'distributed motion control'. Its coming whether you like it or not. I say 'go mad now and beat the rush'.

You may have noted on the NFS Forum video banner a Matsuura VMC machining a part. What may not be evident is that its Ethercat controlled. Interval Zero
have contributed a real-time core and plugin to a basic Windows PC and Kingstar have written an Ethercat module for Mach4.

I'm not suggesting that you leap quite that far yet, Ethercat is at the leading edge of development for Mach4 even if it is well established in industrial applications.
None the less, I am suggesting that you move to a natively step/direction controller and AC servos. If you absolutely require linear scales to be included in the feedback
loop then its not an economic proposition.

Craig
« Last Edit: November 03, 2019, 07:02:35 PM by joeaverage »
My wife left with my best friend...
     and I miss him!
Re: Galil vs Vital
« Reply #4 on: November 04, 2019, 04:21:42 AM »
Craig,

Firstly, let me thank you for the time that you have spent on this.

If I need to feed these new controllers with +/- 10 V surely I would still need something like the Galil card to supply that.  The +/- 10 V is a velocity signal. So if the position loop is closed in the controller how does it know where to stop, if it is not sent a position signal.

I must admit that I had a bit of tunnel vision and did not really consider changing the motors.  I have had the mill for 10/12 years which had been owned by a friend since new.  It came fitted with an Anilam Crusader CNC from new.  It came to me with a complete spare set of motors, drivers and slides.  However, the controller was way outdated and not user friendly.  So my initial motivation was to replace the controller and that is what I focused on, changing the "good" stuff was not considered. 

At the time there did not seem to be many options open to me and I settled on the Galil and Mach3.  The Mach4/Galil plugin was not available then.  I never liked Mach3 and recently it gave me a lot of hassle so I am revisiting the idea of using mach4 with the recommended higher spec card.  Again I only considered the controller side.  However, your comments have widened my horizon somewhat.

If I replace the motors and drivers, as you suggest, then is a PC based system the best way to control them?  Would I not be better off getting an all in one controller/user-interface panel?  To stay with a PC system I would want to make a switch panel, including an MPG and  speed and feed controls to get away from constant mouse usage, then there are mach licences etc.  I would need to replace my 32 bit computer with a 64 bit machine to run the Galil libraries etc.  Without those cash and time expenses it would not be too onerous to go for a complete controller panel.

For a giggle I attach a pic of the old Anilam controller.
Re: Galil vs Vital
« Reply #5 on: November 04, 2019, 07:10:18 AM »
Hi,
there are quite a few questions in your post.

Quote
If I need to feed these new controllers with +/- 10 V surely I would still need something like the Galil card to supply that.

You are correct you would need a Gallil or something like it IF you persist in feeding the servo amps with an analogue signal.
The AC servos I'm recommending are step/direction, not analogue at all. You can thereby avoid the need for a feedback capable
controller.

Quote
So if the position loop is closed in the controller how does it know where to stop, if it is not sent a position signal.

That's what the linear scales are about. They not only drive the DROs but also supply the controller with the current actual
machine position and the controller will compare that to the commanded position and cause the motors to drive in a direction
and speed to match the commanded position exactly.

The AC servos I'm recommending don't need  linear scales because it has a built in encoder. Thus if the position is commanded
to move 10mm to the right and the machine has a 5mm pitch ballscrew the ballscrew must rotate two times. If the encoder
has a 10,000 count per rev encoder (entry level these days) then the trajectory planner/motion controller will issue 20,000
pluses and the servo drive will follow that command and monitor the encoder so that the commanded position is achieved
exactly. In this instance its the servo drive which 'closes the loop' rather than the controller.

Modern servo drives do a very VERY VERY good job of closing the loop, easily as good and in many cases better than
Gallil simply because the manufacturer is making a drive for his servo and he knows them both extremely well. Galil on the other
hand have to accommodate such a wide variety of motors and can't be great at all of them.

Quote
If I replace the motors and drivers, as you suggest, then is a PC based system the best way to control them?

This is a bit of a loaded question. I think it has less to do with whether you replace the servos or not but rather is  'PC the right
way to control a CNC machine?'. The shortest answer is NO. The best way is with a dedicated hardware controller like
a late model Fanuc or Seimens 840. These controllers are worth $20,000 plus. The question is whether you have the budget
to buy a dedicated controller or you can afford a much more humble PC.

A suitable but low powered PC for Mach4, an Ethernet SmoothStepper and a MB03 breakout board, and a Mac4Hobby
license would  cost under $2000 new. That leaves quite a bit of budget for controller panels and pendants etc.
I run my mill on a Mini-ITX dual core Atom board without a graphics card, as the saying goes, 'it couldn't pull the
skin off a rice pudding' but it runs Mach fine. Its 32 bit by the way, Mach4 runs on either 32 or 64 bit without demur.

If you have budget for a dedicated controller like Fanuc or Siemens and a motion controller like Gallil then why mess about
Mach4 or in fact any PC based solution? That you are on the forum suggests that you don't have that sort of budget.
Mach4 is one of the Windows PC based software solutions that can achieve good, surprisingly good, performance relative
to dedicated hardware controllers worth ten and more times as much.

Craig
My wife left with my best friend...
     and I miss him!
Re: Galil vs Vital
« Reply #6 on: November 04, 2019, 08:34:37 AM »
Craig,

Thanks again.  As I said you have widened my horizons towards other and probably better solutions which I will consider without rush.

You are right, it is doubtful that I would be on this forum if I had a high end budget.

The reason that I would need a 64 bit computer is to use the Galil library files if I stayed with the original plan.  They are supposed to work on 32 bit machines but do not. I know Mach4 itself will run on 32 bit and even with Win XP.  When I asked about dedicated control panels I was thinking about the lower end offerings at around $1000 which o/p step and direction data.  Would those signals feed directly into the new servo drives or is an Ethernet SmoothStepper and a MB03 breakout board still required?
Re: Galil vs Vital
« Reply #7 on: November 04, 2019, 10:16:10 AM »
Hi,

Quote
When I asked about dedicated control panels I was thinking about the lower end offerings at around $1000 which o/p step and direction data.  Would those signals feed directly into the new servo drives or is an Ethernet SmoothStepper and a MB03 breakout board still required?

The only dedicated controller I have seen in that price range was a POS Chinese controller fitted to a customers plasma table.
Between the controller and the stand-alone THC unit they were the Achilles heel of the whole setup. I convinced them to ditch
the Chinese crap and get Mach4 and a Hicon, as at that time the Hicon only had THC among the Mach4 motion controllers.

It must be said that the Chinese controller produced step/direction pulses directly to the Mitsibishi servo drives fitted to the
table.

The ESS (or the Hicon come to that) are specifically for Mach (3 or 4) loaded PCs. Ergo they are not required nor would work
with ANY other control software. The MB03 is a breakout board designed to work specifically with an ESS and will only
EVER be partnered with an ESS.

The cheapest quality controller I've seen advertised is a Siemens 803 (three axis) at around $3500 USD (new).

Don't be duped by the Chinese rip-off Siemens look-a-likes......you MUST establish it is the genuine thing BEFORE
parting with a cent.

Craig
My wife left with my best friend...
     and I miss him!
Re: Galil vs Vital
« Reply #8 on: November 04, 2019, 10:45:24 AM »
Craig,

Many thanks, I shall heed your advice.
Your comments indicate that you do this sort of thing for a living or that you have experience with many machines.
Re: Galil vs Vital
« Reply #9 on: November 04, 2019, 10:57:56 AM »
Hi,
I did at one time deal with a few plasma tables but not CNC machining centers, so excepting some experience gained
from customers plasma tables my knowledge is as a hobbyist only.

Craig.
My wife left with my best friend...
     and I miss him!