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new cnc build and smooth stepper questions
« on: January 01, 2013, 10:50:02 AM »
Hi guys,
i have a bf20 mill machine and want to convert to cnc.
I need your help to solve some issues i have. I will use ballscrews but i think also backlash compensation will be needed in mach3.
1) So, is mach3 backlash comp. Working with smoothsteper?
2) is charge pump working with smooth steper?i am thinking the usb ss board with the ss c25 terminal board.so will i have charge pump working?
3) the ss usb board emulates two parallel ports.(if i understand corectly) that means i can use  a simple bob like c10 or c11? Or maybe two bobs?
4)you guys that used both technologies, usb and parallel, what is your suggestions?

Thank in advance for your help.

Offline Hood

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Re: new cnc build and smooth stepper questions
« Reply #1 on: January 01, 2013, 11:14:05 AM »
1. Bcklash has been implemented for probably 1 year or more.
2. Dont need a chargepump with the SmoothStepper. The purpose of the Chargepump was to stop outputs being toggled whilst not under Mach control, ie on booting computer. The SS only loads when Mach is open and has control.
3. Yes you can use 2 breakouts, the USB SS has 2 parallel ports worth of I/O plus an additional 6 inputs on port 3. if you have an Ethernet SmoothStepper then you have 3 parallel ports worth of I/O
4. I have used PP, USB, Ethernet, I would say Ethernet is the one I would choose followed by USB. All depends on your setup however, if you dont need a high pulserate and your computer puts out a stable pulse then the PP may do but the SS will put out a cleaner pulse no matter how good the pulse from your computers PP is.
Hood

Offline Jeff_Birt

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Re: new cnc build and smooth stepper questions
« Reply #2 on: January 01, 2013, 11:33:55 AM »
The only thing I'll quibble with Hood about is item 2, and it is just a minor differnece in opinion. While it is 100% accurate that the purpose of the chargepump was to prevent the machine from doing things as the PC was booting up and the parallel port line might toggle unpredictably; depending on how your BOB is set up the Chargepump might still be useful though as it will act like an enable signal. For example with the Gecko G540 when the chargepump signal is not present all of the outputs will be disabled (stepper motors and relay outputs). When Mach3 starts talking with the SmoothStepper, the SmoothStepper will output the chargepump signal and the outputs will be enabled. If Mach3 crashes for some reason then the SmoothStepper will stop putting out the chargepump signal and all outputs will be disabled. While this is not 100% needed, it is a nice feature to have in place.

Hood is also 100% correct about the ESS being a better choice than the USBSS. I have sold a lot of both units and while 95% (or more) have no issues with the USB versions I have not had a single issue with the Ethernet version dropping out on someone.
Happy machining , Jeff Birt
 
Re: new cnc build and smooth stepper questions
« Reply #3 on: January 01, 2013, 01:16:28 PM »
Ok.
I do not know what board should i combine with the ss. So the next step is to combine a bob, right?
1.do i need a bob with  optoisolated signals feature?
2.should i choose bob with tbe ss conectivity features like c25,c23,c32 or any bob i want? C10,c11

Can you please suggest where to look and what should i give special attention?or maybe a combination?
I am not familiar with equipment like these.and do not know what to start from.i
Thank you guys for your support.
Jeff ,are you selling those devices?any link?

Offline Hood

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Re: new cnc build and smooth stepper questions
« Reply #4 on: January 01, 2013, 01:54:36 PM »
I have always liked PMDX breakouts as they just seem to be bullet proof and exceptional quality, they do a dual port board that suits the SS/ESS.
I know a few people that have them and have nothing to say but good things.
Hood
Re: new cnc build and smooth stepper questions
« Reply #5 on: January 01, 2013, 04:28:43 PM »
Why do you prefer the ethernet type?
Is this choise have anything to do with the instalation and how easy it is to make it work with mach3?
Do both type have the same mach setup?
The usb i think it is faster than a typical 100kbps ethernet.isnt the transfer through ethernet more sensitive  to faults?
Witch one of the pmdx?their site lists the  126 under bobs.is that what you mean?

Offline Hood

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Re: new cnc build and smooth stepper questions
« Reply #6 on: January 01, 2013, 04:57:18 PM »
Ethernet is probably slightly more tricky to set up than USB but its still easy.
Ethernet however is much more stable than USB.
As far as Mach is concerned there is no difference in setup, well you have different plugins but thats all.
Speed is not an issue, it is a buffered system in either case but Ethernet is much more robust.
I have only ever used PMDX122 but port one  is the 126.
Hood
Re: new cnc build and smooth stepper questions
« Reply #7 on: January 01, 2013, 05:39:00 PM »
Is there any lag when ess executes mach commands?
I mean that if i move an axis presing the keys on keybord for example?(that is a mach command, isnt it?)
Or when i will  operate a probe?
The same question please with the pokeys and any pendands?
(The pendands connected straight to the bob or to the pc) ?
I heard many strange things over the internet thats why i decide to ask the source of mach3.
Thanks again Hood!

Offline Hood

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Re: new cnc build and smooth stepper questions
« Reply #8 on: January 01, 2013, 05:58:33 PM »
No there is no delay in either USB or Ethernet when jogging, well there will be a delay but it will be in the milliseconds or less.
Probing and threading (lathe) are handled in the driver when using the parallel port so they need to be handled by the external controller when using one. In other words if your external controller supports probing or threading they should be as good if not better than the PP. I have not used probing in the SS or ESS but I do know it is implemented. I have used threading and it is slightly better than the PP.

Pokeys or whatever should be the same but it may depend on their plugin. Early plugins for the Pokeys were very poor on MPG motion but I think they are good now.

Hood
« Last Edit: January 01, 2013, 06:09:00 PM by Hood »