Mesa cards for a Fadel VMC

I am helping a friend that is retro fitting a Fadel VMC with 16 pocket tool changer.

The machine is fitted with DC servos with resolvers that are going to be replaced with AC servos.

So requirements are Mesa cards for :-

3 No. AC servos with encoders step/dir closed back to linuxcnc
1 No. AMC DC servo with resolver analogue +/- 10V (4th axis)
1 No. AMC VFD flux vector drive encoder
1 No. MPG
Various input/outputs toolchanger etc.

Was thinking 7i76e + 7i85 + ??

its a bit awkward with one analog servo (and perhaps analog VFD)
But you could add one 7I83 to get some analog output channels (6)
and perhaps replace the 7I85 with a 7I89 so you aren't so close to running out of encoders

PCW wrote:

its a bit awkward with one analog servo (and perhaps analog VFD)
But you could add one 7I83 to get some analog output channels (6)
and perhaps replace the 7I85 with a 7I89 so you aren't so close to running out of encoders

Would the 7i83 cover the AMC DC servo with resolver analogue +/- 10V (4th axis)

Does the AMC drives resolver go to the drive or the controller?

PCW wrote:

Does the AMC drives resolver go to the drive or the controller?

Peter. Thanks for the feedback.

I believe that the AMC resolver was connected to an axis card (there a 4 of them in the machine but jumpered for the A axis) and there is another card called a clock card that is also connected.

Is this what you was asking?

Yeah basically...
Unfortunately its very awkward to support just one resolver with Mesa cards
It might be easier to add and encoder to the 4th axis

Do you have any documentation on the 4th axis drive?

Peter. To stop any confusion by me my friend has just signed up as Dean A so the questions will be first hand.

Many thanks for the help with this.

Clive wrote:

Peter. To stop any confusion by me my friend has just signed up as Dean A so the questions will be first hand.

Many thanks for the help with this.

Thanks, Clive.

Hi Peter and thank you for taking to time to look at this.

I don't have any Docs for the 4th axis only the model number of the Drive SMA7377-1, which by the way is a Glentek, not AMC as I first told Clive. AMC were fitted on X, Y, Z. However, the connections and specs are exactly the same.

Here's Little background on what was fitted:
The Fadal DC Servo System was made up of 3 parts. Drive, Axis card and Clock Card.
I believe the Axis card deals with Resolver feedback and Analog +/- 10v generation for the drive. It also reads Current feedback from the motor.
The clock card generates the clock signals for all axis cards and Sin / Cosine waves for the resolvers. It also deals with feedrate override input from a Pot.

The Axis cards and Clock card plugged into a Backplane motherboard that connects with CPU, Graphics, I/O cards, etc that make up the Controller.
All this I've removed(But still own) and want to replace with Linux/Mesa. The only thing I've kept from the original setup is the A-axis Drive and Motor.

Ideally, I was hoping could use a Resolver Card and keep Orginal. However, if it makes too difficult or costly then I'll swap Resolver to Encoder if it's possible.
I Even considered Swapping the DC Motor for AC Servo but that's not so simple. Also to keep the footprint small they remove the Rear Motor cover which will reduce the resale value or saleability of the motor.

Hope this helps.

I’d like to buy your Fadal control boards, I still have a Fadal that runs the original control.
I’m curious as to why on such a small machine you want to replace the dc motors with ac motors. I’ll be the first to admit that they are not of Yaskawa quality, but they are more then adequate . Seems it would be easier to keep the motors and resolvers. Much cheaper also. Why would you also choose step and direction over analog on a servo system, your spindle drive is 0-10 v?
Fadals don’t have limit switches, they home to a grid on the resolver. You will have to write a homing routine.
I’d go 5i23 with a resolver card use a 24 space opto rack for I/o an you are done if you use a mouse touch screen. If using an actual operators panel, I’d go with smart serial I/o for the whole machine.

JR1050 wrote:

I’m curious as to why on such a small machine you want to replace the dc motors with ac motors. I’ll be the first to admit that they are not of Yaskawa quality, but they are more then adequate . Seems it would be easier to keep the motors and resolvers.

The main reason is the availability of spares as I'm located in the UK where spares and Knowledgable engineers for Fadals are hard to find and very expensive when found.
The Machine itself as done very little work and mostly in Brass so not been stressed. However, it was unused for 6 years by the previous owner due to serious motorcycle injury. So while he took precautions to stop it rusting from our Wet and Cold UK weather I suspect he didn't take any regards the Electronics. So when he fired the controller up again I think some of the cards must have been damp and blew. He called a service engineer and together they came to the conclusion it was uneconomical to repair.

So when I received machine the Control wouldn't startup, the screen was just scrambled and the Z-axis card was dead. The Fadal Importers are not very helpful and basically said just swap cards for new ones until find which is faulty...WTF!!
However, I pretty much expected this response and bought the machine knowing I'd be retrofitting it out. So if I'm going to all this effort I decided to bring it into the 21st century and fit AC servos because the spare situation isn't going to get better.
I know the existing DC servos are more than good enough and reasonable quality but the resale value of these and boards from control will pay for most of Re-fit.

JR1050 wrote:

Why would you also choose step and direction over analog on a servo system,

No reason other than AC servo drives can accept either analog or Digital and I was under impression Step & Dir was simpler.!.
While I've lots of experience of Stepper systems and some AC servo experience with Step & Dir from building Routers, I've very little with Analog DC servo systems. What are the advantages to analog over step & Dir in an AC servo system.?

JR1050 wrote:

your spindle drive is 0-10 v? .

The AMC Documentation says Spindle Drive can be used with either +/-10v or 0-10v. depending on how you switch the Fwd/Rev inputs.
I've tested the spindle with 0-10v and switching fwd/Rev and it does work fine. The Spindle card was ridging tapping card and used +/-10v so both fwd/Rev inputs were switched together.
So again what are the advantages of +/-10v over 0-10v and switching fwd/rev inputs separately.? I would imagine it's smoother.!
I was planning to use +/-10v as it did originally if possible. Again my lack of LinuxCnc/Mesa experience means I'm still unsure about which route will be taken.

JR1050 wrote:

Fadal's don’t have limit switches, they home to a grid on the resolver. You will have to write a homing routine.

The plan is to fit Switches and then have drive Home to Index pulse and return signal when done. I'm completely new Linux CNC but have written many custom scripts for Mach3 so writing a homing routine doesn't phase me if needed.

Thanks for the input and advice. At the moment I've not done anything about selling the cards etc until I've decided on the exact route I'm taking. I'm still undecided if need 4th axis so I may just sell the Whole 4th Axis and keep it simple taking the whole Analog axis issue away.? However, when I'm ready I will drop you a message.