Automation Direct AC servo systems

[5th-axis]

Hello,
We have been looking at replacing our DC servos with the AC servos from Automation Direct. The prices I saw listed include the drive, servo and cabling for around $1500. This is way cheaper than a new servo from Fadal which I think comes in at around $2200. Has anyone here in the forums done this swap? Our machine is a 1993 6030 with a Numatix retrofit. The control is awesome but I think the machine could use a little updating to keep it going.

Thanks guys,

[mactec54]

5th-axis

You need to look at the spec very carefully, check what you have in the way of encoders, the ones you are looking at are only 2500 count, way to low for a good CNC machine

[5th-axis]

Mactec54,
Thanks for the reply. My machine is a glass scale machine so the encoders would not be used.
Thanks again

[JR1050]

I would think a 1993 fadal would still have resolvers,especially if it has dc glentek motors.Fadal used the resolver as an absolute pos device(hence no limit switches).If you still have resolvers,you will have to put them on your new motors,If you have encoders,Im sure there is a parameter in your control to set the encoder count. 2500ppr is fine,in quadature,its gonna be 10,000 ppr!Go for it and let us all know how it works!!

[Neal]

1993 machine did indeed have DC servo motors. The casting machining may pose an issue to install AC servos. Also the Eproms on the 1010 controller cards will NOT accept feedback from AC servos. They will need to be changed. The AC encoder count MUST be 8192 for the software to function properly.
Bottom line is that this is NOT a simple put a different motor on.

Neal

[5th-axis]

I looked at the mounts for the current servos and I believe I can make new mounts for the AC servos with no casting machining required. Please keep in mind that this machine is a Numatix retrofit and the company who did the retrofit initially brought these servos to my attention. He also mentioned that I could do each axis servo seperately as budget and job constraints allowed. When we did the retrofit the resolvers were unhooked. The limits are set in software in the control. I absolutely love the Numatix control and the tunability it has.

[ishaham]

Dear Numatix user

There is no problem to replace the motor with the Automationdirect system, you can email me you email address and I will send you a coplete instruction how to replace it and how to set the control to accept the new system and how to tune the new system

Igal

[ishaham]

Originally Posted by Neal 1993 machine did indeed have DC servo motors. The casting machining may pose an issue to install AC servos. Also the Eproms on the 1010 controller cards will NOT accept feedback from AC servos. They will need to be changed. The AC encoder count MUST be 8192 for the software to function properly. Bottom line is that this is NOT a simple put a different motor on. Neal

Hi Neal

I would be very happy to educate you about the Numatix Control, or you can look at our web site www.numatix.com, we do have a special kit for Fadal that runs ~$20,000 installed, we guaranty increase of 100% of productivity or your money back, we also have a kit that we can install without removing the original Fadal for customers to try for 10 days, after this they can decide, if they dont like it, it takes about 30 min to restore to original system no strings attached

[ishaham]

Originally Posted by mactec54 5th-axis You need to look at the spec very carefully, check what you have in the way of encoders, the ones you are looking at are only 2500 count, way to low for a good CNC machine

2500 counts on a 6.35mm pitch will give you .000025" resolution which is good enough for fadal or any other mills

[ishaham]

I agree with the resolution, but the resolver is used just for position and reference, when we retrofit with the numatix we remove the resolver and install encoders as part of the installation

[mactec54]

ishaham
Quote
2500 counts on a 6.35mm pitch will give you .000025" resolution which is good enough for fadal or any other mills

If your Numatix control is that good, why would you say that 2500 count encoder was good enough for his machine, have you seen how a large count encoder 17bit / 20bit will make a machine like this run, or can your control not handle a large count encoder

As I have said before in other posts it has nothing to do with resolution, when you have a large count encoder,the drives take care of the encoder, it's how well the machine will run with a large count encoder, supper smooth & fast, You will not get this with a 2500 count encoder

2500 count is from 20 years ago, modern machines have nothing less than 13bit most have 17bit & higher

[ishaham]

Dear Mactec54,

First, the servo is responding to the control’s command. The control defines the motion parameters, not the servo. In most systems, such as Fanuc and Siemens, the motion servo loop in the control has a ~2 msec response time. With this response time at 100 ipm, the control will see the position after ~.003” of motion has already been executed. This lag causes the control to have to “catch up” to the current position of the servo.
The Numatix has a .2 msec servo loop, which is approximately 10 times better than most controls out in the market. With this .2 msec servo loop at 100 ipm, there will be an error of a maximum of .0003” before the control will make the correction.
The smoothness of motion has very little to do with the encoder counts. The smoothness of motion DOES have to do with the ability of the control to process the data fast enough to push the servo to its maximum potential.
In the aspect of processing speed, the Numatix is superior to most controls. The average processing time of most controls ranges from 600 to 2000 blocks per sec, where the Numatix does over 50,000 blocks per second. The processing speed is the reason why when you program at 100 ipm on most controls, you can only achieve an actual average feed of 30-50 ipm. The control has to slow down whenever it gets to a dense amount of data points in the program, just to allow the control to process the data and not lose control of the motion. Of course, the “look ahead” is also a factor. That is why Fanuc, Siemens and other controls invented the NURB feature which reduces the amount of points to “help” the control digest the data, and by doing this increasing speed, but at the cost of degrading accuracy and surface finish.
With that being said, I believe 2500 PPR quadrature that makes it 10000 is good enough for any control.