Dynomotion

Group: DynoMotion Message: 8823 From: andy.brman Date: 12/27/2013
Subject: 5 Axis CNC with 6 Steppers
I am still in the early stages of an new CNC build.
Wondering if anybody has advice as to a good way to drive six steppers with a KFLOP,KSTep, and Kanalog.
I haven't bought steppers/encoders yet, but I have been reading up on the forum for advice.

Specifically, I am wondering how slave motors are generally hooked up with the KSTEP.
In my case I would like to drive the Yaxis with one stepper on each side. The gantry span is over 8 feet.
I have two stepper drivers in addition to the KStep that I am thinking will be able to work with my set up.
They are:
http://www.automationtechnologiesinc.com/docs/manuals/KL-5056D.pdf
and
http://www.geckodrive.com/g201x.html
I am looking for General advice as to which boards would drive the steppers.
I am thinking axis X,Y(bothSteppers),Z would be driven via the KSTEP and The Kanalog could bring in encoder information for all Steppers and send Step and Direction signals to the L:-5056D and Gecko-G201X.

any words of warning or advice are welcome.
Thanks.
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Group: DynoMotion Message: 8824 From: Tom Kerekes Date: 12/27/2013
Subject: Re: 5 Axis CNC with 6 Steppers [1 Attachment]
Hi,

Are your encoders single ended or differential?  See:

http://www.dynomotion.com/faq.html#Encoders

It is not common to use KSTEP with Kanalog.  There are some limitations.  See:

http://www.dynomotion.com/faq.html#kanalog_and_kstep

Step/Dir signals must come from KFLOP not Kanalog.  See:

http://www.dynomotion.com/faq.html#third_party_step

Unfortunately the KL-5056D.pdf requires a long Direction Setup Time (5us)  which KFLOP does not currently provide (max = 4us).  The Gecko will have no problems.

HTH
Regards
TK

Group: DynoMotion Message: 8825 From: andy.brman Date: 12/27/2013
Subject: Re: 5 Axis CNC with 6 Steppers [1 Attachment]

O.k.

Well, I haven't bought the Steppers or encoders yet. It sounds as though using both the KStep and Kanalog with my particular Stepper/Encoder needs isn't possible?

Would it make more sense to take the Kstep out of the equation and Run all Step Direction commands for all 6 Steppers from KFLOP (with 3rdParty Dives like the Gecko201X), while using the differential inputs (Jp2) on Kanalog for Encoders.

Since I haven't bought the encoders yet, I suppose I could get Single ended ones that would work with the KFLOP.


Do you have a recommendation? 

I do intend to use some of the DAC's and ADC's and Serial Out capabilities of the Kanalog.... so it is hard for me to imagine a scenario where the Kanalog is not in the mix.

Thanks
Group: DynoMotion Message: 8826 From: andy.brman Date: 12/27/2013
Subject: Re: 5 Axis CNC with 6 Steppers [1 Attachment]
I forgot to ask how a Slave axis is driven.
Is it essentially treated as it's own axis from a Hardware point of view?

I guess if I have encoders, then this would definitely be true... if I didn't have encoders, then perhaps the Step/Direction signals could could be used for two STeppers?
Group: DynoMotion Message: 8827 From: Tom Kerekes Date: 12/27/2013
Subject: Re: 5 Axis CNC with 6 Steppers
Hi,

Its awkward cabling wise, but it is possible to use KSTEP or 3rd party Step/Direction drives with Kanalog.  It just requires special wiring so you lose some of the plug-and-play aspects of KSTEP and the extra KSTEP IO.  KSTEP is basically just a 4-axis Step/Direction drive.  So using 3rd party or KSTEP drives is an independent decision.

I recommend purchasing differential encoders.  They can be used with single ended inputs, but if you decide later on using differential you have the option.  There are also 3rd party modules to convert differential to single ended.

So one solution with Kanalog, 6 Step/Dir, 8 encoders might be:

For 6 Step/Dir Generators
    KFLOP JP5 provides 4
    The Mux Option Provides one on KFLOP JP4 and one on KFLOP JP6

For 8 differential encoders:
    Kanalog provides 4 differential inputs that enter KFLOP JP7
    Kanalog provides 4 more differential receivers that can be re-wired from Kanalog JP9 to enter KFLOP JP6
   
Regarding Slaving: From a Hardware perspective they should be wired as separate axes.  Then slaved in the configuration.  See:

http://dynomotion.com/Help/ConfigurationScreen/ConfigurationScreen.htm#Master/Slave_Settings

HTH
Regards
TK



Group: DynoMotion Message: 8828 From: andy.brman Date: 12/27/2013
Subject: Re: 5 Axis CNC with 6 Steppers

Tom,

Thanks for the quick reply...plus all the good information.

you mentioned "So using 3rd party or KSTEP drives is an independent decision."

>>> I would prefer to use the KStep for at least 4 of the steppers since I have it, and I like its characteristics (performance/cost ratio).

so that brings up some questions:

1.    I don't understand how I could get six differential encoder inputs if I do use the Kstep in the mix. I was thinking that JP2 would need to provide at least 2 of the 6. (but I am not sure about that)
2.    Is it crazy to think that running 2 Kflop boards could simplify things?  my thought is that rather than buying additional 3rd Party drivers for the steppers not covered by the Kstep... I could purchase another Kstep. This would mean I would set up Kflop 1 to run Two Kstep Boards, and Kflop2 to run the Kanalog board that I have. I know this would be overkill by at least 2 axis and heaps of I/O that I would probably never use... but it seems way cleaner in terms of setup and possible modifications down the road.
3.If question 2 makes any sense, what sort of additional complexity would I be taking on in terms of programing to get a system like this working. I did read through this help page about multiple boards
http://dynomotion.com/Help/MultipleBoards.htm
it mostly deals with setup of hardware.. I am curious C programs and KmotionCNC work with multiple boards.

Back to question 1.. I included a hacked together diagram of connecting a Kanalog,Kflop, and Kstep for my needs.... as I understood it from your description.  Can you let me know if it seems off...
Thank you so much for helping me wade through this complexity,
Andy
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Group: DynoMotion Message: 8829 From: Tom Kerekes Date: 12/28/2013
Subject: Re: 5 Axis CNC with 6 Steppers [1 Attachment]
Hi Andy,

Using 2 KFLOPs would complicate things.  It would be difficult to coordinate things between the two boards.  KMotionCNC only works with one board at a time.

Regarding your diagram:

#1 Step/Dir inputs to KSTEP can be connected to either KSTEP JP36 or JP26Connect.  So for simplicity sake connect KFLOP JP5 to KSTEP JP26 (not JP36) with a simple 1:1 RJ45 cable.
#2 Kanalogs 8 differential receivers on Kanalog JP2 are converted to single ended signals and come out Kanalog JP9 and normally connect to KFLOP JP5, but since KFLOP JP5 is not available, you must wire them with a custom cable to KFLOP JP6.  Then all 16 differential inputs on Kanalog JP1 and JP2 will be connected to KFLOP as IO 0-7 and IO26-35. 

HTH
Regards
TK