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Author Topic: 500L Encoders, should I upgrade???  (Read 3845 times)

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500L Encoders, should I upgrade???
« on: May 23, 2015, 01:33:34 PM »
Hi Folks,

I am preparing to replace a Dynapath 10 control on my Tree J310 mill with the CSMIO/IP-A control. I'll be keeping the existing servo motors and servo amps. (Baldor BIG-MHO motors and Servo Dynamics 1525 amps)  I have two questions before I get started that I hope folks can help me with:

1.) Current encoders are 500L differential so 500 x 4 = 2k p/rev. CS-Labs offers upgrade encoders which seem reasonably priced. I think the current encoders are likely sufficient for all the work I do but I wonder if others may have first hand experience with 500L vs 2500L encoders offered from CS-Labs.

2.) I want to add an MPG pendant. The unit offered by CS-Labs looks solid and I like the fact that the e-stop on that unit is included. I also see MPG pendants that work through software with Mach and they are suspiciously inexpensive. My inclination is that the MPG connected directly to the machine control is a better design but I wonder if anyone has direct experience and can recommend an MPG.

Thanks!
J. Mike Colee
Santa Barbara, CA

Offline Hood

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Re: 500L Encoders, should I upgrade???
« Reply #1 on: May 23, 2015, 05:04:27 PM »
You will likely be ok with the 500 line encoders although from personal experience I have found the higher the resolution of the encoders the tighter tuning I can get. The motors I have use Sine/Cosine smart encoders and I can interpolate them via the servo drive, I found as I increased the interpolation the easier it was to tune.
 As said however the 500 line ones will likely suffice and if you want then later on you could swap out.

I would go with the MPG module at least, the motion from the MPG connected via the IP-A when using the MPG module is far superior to that of using Machs own MPG controls. It works like Industrial MPGs where you have  x1 x10 x100 (or x10 x100 x1000) and it is very accurate each step where Mach has Velocity mode which is just an approximation per click and if you put into multistep you can get accurate steps per click but motion is jerky.

I personally do not like hand held pendants so I just use the MPG module and fit buttons, rotary switches, pots and MPG to my control panel and the MPG module makes that all work easily and nicely :)

Hood
Re: 500L Encoders, should I upgrade???
« Reply #2 on: May 26, 2015, 04:14:44 PM »
Thank you Hood,

These forums are turning out to be a great resource. I'll post back as my project proceeds. I'll stay with 500L encoders for now. Your lack of need for an MPG pendant is intriguing... Perhaps I too will find I don't need one. I am coming from a position of several years of experience with my beloved bridgeport manual machine so perhaps I feel like I need to get my hands onto a hand-wheel be it physical or virtual  ;D I have ZERO experience with a CNC mill. As for Mach... I have a lot of learning to do there too... I assume the MPG module you speak of is a soft version of an MPG usable from Mach screens?

Thanks!
J. Mike Colee
Santa Barbara, CA
 

 

Offline Hood

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Re: 500L Encoders, should I upgrade???
« Reply #3 on: May 26, 2015, 05:28:08 PM »
What I am meaning is I am not a fan of the handheld pendants but I could not be without the actual MPG (Manual Pulse Generator) ie the actual handwheel. For that you are best using the MPG module from CS-Lab.
I do not use it for machining as MDI is much easier and better, but I do use it constantly for positioning such as touching off workpiece etc.
Below is a pic showing my panel with the switches and MPG etc.
Hood
Re: 500L Encoders, should I upgrade???
« Reply #4 on: May 26, 2015, 11:39:58 PM »
Wow that is one trick OP. Thanks for sharing the photo. I see now what you mean in that you prefer your MPG fixed to the OP rather than dangling by a cord. Thanks for clarifying that.

Thanks!
J. Mike Colee
Santa Barbara, CA
Re: 500L Encoders, should I upgrade???
« Reply #5 on: June 08, 2015, 02:29:33 AM »
hello freinds'
i just started to check my retrofitting using CS-lab CSMIO-A.

really, i brought the machine running in 3 axes with a good time response from the Keyboard pressing button.

my problem now is that i am not sure if the PID is tunes properly , or the axes and motors StepPer is OK.

when i started to run, sometimes i got not correct mesurment about 1-1.5 mm  diffrence in X axes and Yaxes.

i checked with dial gauge the movments and then i scaled the "Step Per" ,but it seem that the diviation is vary according to movment.

my first check show that there is no mechanical backlash in the machine.

so i dont know if an unproper PID tuning in the PlugIns cause this problem.

is this diviation in the measurments came because of large Following error or high speed moving?
by the way, the maximum speed of the machine is 8000mm/min even the machine could run faster but i tried now slower to see were is the problem.

pleaese advice'
Ghantos