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Re: servo selection.......
« Reply #10 on: October 02, 2008, 02:48:37 AM »
what about using mach in closed loop. Along with the 1:10 gearbox  (bonfiglioli gearbox)
I guess it will improves the performance.

Well yashkawa servo accepts 200kps maximum.
« Last Edit: October 02, 2008, 02:52:15 AM by ashish »

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Re: servo selection.......
« Reply #11 on: October 02, 2008, 03:08:23 AM »
In the future closed loop may be a possibility with Mach  but at this time Mach is open loop. At the moment the servo drives close the loop and they will attemp to get the motors to the position that Mach tells them to go, if for any reason they do not get there then the drives will fault and you can send this fault signal to Mach and it will halt outputs from Mach.
 On my drives I have the following error set to 20 counts, that equates to 0.0125mm of axis travel and I have not had a fault due to that yet :)

Not sure where you are wanting the gearbox, I have all of my motors connected direct with no reduction, with 2000 line encoders that  is 8000pulses per rev from Mach so the resolution for me is 5mm pitch / 8000 = 0.000625mm (0.0000246 inch) ,  dont think you need any better than that ;)

Hood
Re: servo selection.......
« Reply #12 on: October 02, 2008, 03:35:30 AM »
Hood
0.000625mm is more than enough but let me check what a siemens 810 is capable of.
What CAM and CAD software u r using.
I got Solid Works 2005..............but looking for freeware or open source CAM package.
I want to use gear box with tool indexer......................that would be last mod for the machine but its better to get all things in budget before.

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Re: servo selection.......
« Reply #13 on: October 02, 2008, 06:28:12 AM »
Your resolution would actually be more than that as you have 10,000 pulses per rev so presuming you have 5mm pitch ballscrews then it would  be 5/10000 = 0.0005mm (0.0000197")

 Not sure what you are meaning by "Well yashkawa servo accepts 200kps maximum."

Hood
..
« Reply #14 on: October 02, 2008, 07:01:08 AM »
Not sure what you are meaning by "Well yashkawa servo accepts 200kps maximum."

That means 200,000 pulses per second is the pulse rate which servo can accept for the position velocity.
200,000 pulse per second = 3000rpm

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Re: servo selection.......
« Reply #15 on: October 02, 2008, 07:11:12 AM »
OK but 200KPS is not 3000RPM, you have 2,500 line encoders so that is 10,000 pulses per rev as far as Mach is concerned. So 3,000RPM = 50Revs per second, multiply 50 x 10,000 pulses and that equates to 500KHz (Kps as Yaskawa are calling it)
 The only thing is there is a possibilty that Yaskawa, because they state Kps rather than KHz , so their 200kps would actually be 800KHz and in that case you will be fine.

Hood

edited with right number of revs per secong ;D
« Last Edit: October 02, 2008, 12:22:23 PM by Hood »
Re: servo selection.......
« Reply #16 on: October 02, 2008, 09:16:26 AM »
can i ask u what kind of isolator u have used between servo's and lpt port.
coz yashkawa servo accept's 24vdc npn logic.
Re: servo selection.......
« Reply #17 on: October 02, 2008, 10:50:12 AM »
OK but 200KPS is not 3000RPM, you have 2,500 line encoders so that is 10,000 pulses per rev as far as Mach is concerned. So 3,000RPM = 500Revs per second, multiply 500 x 10,000 pulses and that equates to 500KHz (Kps as Yaskawa are calling it)
 The only thing is there is a possibilty that Yaskawa, because they state Kps rather than KHz , so their 200kps would actually be 800KHz and in that case you will be fine.

Hood

Hood,

    3000 / 60 = 500?  Looks like the ol' Casio may be ready for new batteries....  :-)

Regards,
Ray L.
Regards,
Ray L.

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Re: servo selection.......
« Reply #18 on: October 02, 2008, 12:20:41 PM »
Hood,

    3000 / 60 = 500?  Looks like the ol' Casio may be ready for new batteries....  :-)

Regards,
Ray L.

oops, bit of a typo there but the final figures are correct I think ;) just put an extra zero in, I have an excuse, I was running the mill, the lathe and also drawing a ciorcuit board up while I was working it out and replying , well thats my story and I am sticking to it ;D

Hood

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Re: servo selection.......
« Reply #19 on: October 02, 2008, 12:24:48 PM »
ashish

I have various means of doing that, first thing is my Step/Dir inputs to the drive are 5v and I would imagine the Yaskawas would be the same, so no need for anything there. The rest of the I/O on the drive is either through a PLC or things like limits are through relays to the PC.

Hood