Retrofitting a Shizuoka AN-S 3 axis knee mill

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18 Sep 2021 22:28 #221044 by FortheShiz
I didn't realize that there was an option straight from a Mesa card to analog style drives. It makes me curious about trying to use my original drives. I was under the impression I would need to use a digital to analog converter as I have seen being sold. Essentially either way I should need one of the 7I series cards though and then the 5I are basically for expanding the amount of IO. That already helped clear so much up haha you continue to be a major help I can't thank you enough haha. Definitely going to consider reusing my analog drives as I might be able to get things moving with basically just the 7I77 and a PC. As long as it has enough IO for the required safety sensors and such. Don't want to completely cheap out but the prospect of doing the conversion so cheap with the ability to upgrade later with only the 7I77 really being wastefully replaced is appealing. Do you happen to know any resources for learning about testing analog servo drives without first having something like the 7I77? Would definitely reuse them for now if I could tset they are working before buying any parts.

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18 Sep 2021 22:51 #221045 by tommylight
You would also need just 1 of these to connect to a Mesa 7i77:
5i25 PCI card
6i25 PCI-E card
7i92M Ethernet, can be attached directly to 7i77 with no cables, notice the M.
There is also Mesa 7i97 that has all in one place and is ethernet.
Ethernet makes things really neat when operator console is in front and the electronics box on the back as it requires only a single ethernet CAT5E or CAT6 cable.
For some info on wiring and testing procedure, have a look here:
forum.linuxcnc.org/10-advanced-configura...ning-detailed-how-to

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19 Sep 2021 16:27 #221116 by Muzzer
Note that the cncdrive drives (being digital, microcontroller-based components) use step/dir signals, not analog +/-10V. If you plan to operate the existing analog drives, you would need a 7i77 but if you planned to move over to step/dir later you'd then need the 7i76.

I expect you might be able to reverse engineer your existing system and find the +/-10V inputs to your drives. Bear in mind though that the minute one of those drives popped, you'd likely be faced with a scrap system. You may be able to find replacement parts if you are lucky but they must be antiques now. Personally, I'd rip out all the old electronics apart from the motors and start again with modern replacements, LinuxCNC controller etc and be done with it. If you find you need to replace the bearings, so be it - they aren't expensive on this machine. But are you really likely to dispose of the machine instead?

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19 Sep 2021 16:58 - 19 Sep 2021 17:16 #221119 by FortheShiz
I have been look all evening and this morning for a solution to that problem haha. I have been trying to see if I can save any money (up front only) by using the analog drives until they die. I was looking at things like the 7i33 which seems to be essentially a digital to analog converter since I could then potentially take that card away when switching to digital drives but I am not sure what other card would be best to use it with. One thing that I am very curious about is if it is possible to run digital and analog drives simultaneously with a combo like the 5i25 + 7i76 +7i77. That way I could replace drives one at a time as they fail. I imagine this could still save significantly over buying Mesa cards and 3 digital drives up front. It would cost the price of the 7i77 extra eventually after all drives had failed and been replaced but I wouldn't cry about have an extra card around for other projects and I would be spreading out my spending. Any thoughts?

Also definitely not getting rid of the machine unless there is something beyond fixing on it.
Last edit: 19 Sep 2021 17:16 by FortheShiz.

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21 Sep 2021 10:01 #221257 by Muzzer
Be aware that the "digital" step/dir signals provided to modern drives are a stream of pulses, each pulse representing a demand for a move by a defined increment. I don't know much about the 7i33 but on the face of it, a "D to A" converter wouldn't be able to convert a pulse stream to an analog 0-10V voltage, so the scheme you suggest doesn't sound workable to me.

Perhaps starting with a 7i77 and the existing analog servo amps, then moving to the 7i76 with step/dir drives would work as you suggest. From what I know you could swap drives over but you'd want to check with someone who knows.

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