Fanuc retrofit retaining original AC servo motors and drives

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26 Feb 2019 14:38 #127160 by mclausen
I have a Kitamura MyCenter 1 with a Fanuc 10M control that I would like to convert to LinuxCNC. This is a fully functioning machine, the only problem is that limited memory, and maximum 9600 Baud DNC make it difficult to do 3D surfacing, and modern constant load tool paths without pausing for the data to catch up. I would also like to add a 4th axis.

This has A06B-6057-H004 (X and Y axis) and A06B-6057-H005 (Z axis) digital drives that get the commutation from the control. The encoders are not serial, and have the 4 commutation channels.

I have found several threads discussing this type of retrofit, but I have not found any conclusion if anyone has successfully completed one. Is this possible?

It looks like the bldc component in LinuxCNC has the ability to interpret the Fanuc gray scale encoder commutation, and provide 6 PWM outputs for the drives, but in a previous post PWM, mentioned that it would take a custom daughter card.

I could swap the drives out for older A06B-6050 analog drives, but I would like to know if someone has successfully done this.

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27 Feb 2019 10:28 #127231 by pl7i92
there are Fanuc Retrofits in the Forum Discussed

IF You are able to get some Electronic Modification Meaning Wirering up
I Gues the /I77 will be best to go for as you can reatch full 3D serfacing at a upp to 20m/min speed
your Center is constructed to a max of 5m/min at 7KW

The Encoders will fit the Mesa Stuff

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27 Feb 2019 15:46 #127251 by andypugh

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27 Feb 2019 16:26 #127258 by mclausen
Thanks for the replies.

pl7i92,
The 7i77 is an analog output board. Are you suggesting that I need to replace my drives with the older analog ones? Will the control be faster with the analog drives as it does not require the 6 channels of pwm per axis? Also is it possible to get the feeds beyond the current 5m/min? How much of this limit was due to the old Fanuc control speed? The rapids are limited to 12 m/min, so the max would be somewhere below that.

Andy,
That encoder module looks it is for the serial encoders. Does it require custom firmware? Does it handle the absolute encoders? Would a backup battery need to be added? Most of my encoders are not serial, but the 4th axis I have has an absolute AA64 serial encoder. I was going to swap out the motor for an older one to get the quadrature encoder, but it would be nice to have an absolute on the 4th axis as depending on what is mounted, it may not be possible to do a full rotation to home.
Also if I use this mesa module, I assume I would need to stick with the digital drives and pwm output, as the analog drives get commutation directly from the older encoders.

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27 Feb 2019 16:36 #127260 by andypugh
It would be possible to run both sorts of servo. This would need a custom firmware, but I am fairly sure you would need that anyway.

I would be looking at the Mesa 5i24 as the FPGA card, just as it has the most pins for the pound (or bits for the buck, IO for the Euro, whatever)

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27 Feb 2019 17:08 #127272 by mclausen
Thanks. I used a 6i24 for my lathe retrofit, so that or a 5i24 will be a good place to start.
I would like to stick with the 6057 digital drives, as I already have them, and I know they are functioning. I just would need to buy one additional drive for the 4th axis. I would feel more confident about that route if I knew someone else had successfully got that going.

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01 Mar 2019 12:33 #127400 by andypugh
I don't think it has actually been done yet. So you have a choice between an interesting project or replacing the drives.

It is probably worth trying the "project" first, I think initially that just requires a suitable firmware and some TTL to (whatever) conversion.

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02 Mar 2019 16:23 #127516 by mclausen
It looks like it will be a lot easier to swap to analog drives. The digital drives would require 6 pwm and 7 encoder signals per axis.

Th next question I have is about layout. On my lathe I stuck the motherboard right behind the touch screen as this was also close to the servo amplifiers. On the mill, from the control panel to the main electrical box would take at least 15 ft of wiring. Do I put the motherboard with 5i24 in the main electrical box and run long monitor/ keyboard cables, and also put a remote I/O board in the control panel? Is there a speed advantage to use a ribbon cable connected 7i48 servo card vs a serial connected 7i83 remote servo card?

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02 Mar 2019 16:44 #127518 by andypugh
I suggested the 7i84 as a card with lots of pins for PWM. If you are not gonna that way then maybe an Ethernet card is the way to go? It would simplify wiring.

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11 Apr 2019 02:48 #130638 by mclausen
I purchased the components for the computer, and now I need to order Mesa boards. I counted that I will need approximately 100 gpio signals on top of the encoders and servo signals.
Here is what I am thinking:
6i24 PCIE FPGA card
7i48 6 channel analog servo
7i46 SPI breakout board
4 or 5 7i50 I/O expansion cards

Does this sound like a reasonable combination?
Can the 7i50 handle a MPG encoder?

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