3axis CNC retrofitting with LinuxCNC
- terans1085
-
Topic Author
- Offline
- Junior Member
-
Less
More
- Posts: 38
- Thank you received: 0
29 Mar 2014 20:09 #45372
by terans1085
3axis CNC retrofitting with LinuxCNC was created by terans1085
Hello guys&gals,
First of all I would like to thank the LinuxCNC team for a great looking software and site!
I am in the process of retrofitting LinuCNC on an old 3axis woodworking cnc router, however, this being my first time, (both at CNC, and at Linux) I got stuck.![:blush: :blush:](/media/kunena/emoticons/blush.png)
The machine is fitted with servo motors complete with controllers which have speed/direction input +/-10V.
Feedback is given by incremental encoders attached directly to the motors, 500pulses/rev.
Is a PC with 1/2 parports sufficient? Do I need additional hardware?
Any help is appreciated![:) :)](/media/kunena/emoticons/smile.png)
Thanks!
First of all I would like to thank the LinuxCNC team for a great looking software and site!
I am in the process of retrofitting LinuCNC on an old 3axis woodworking cnc router, however, this being my first time, (both at CNC, and at Linux) I got stuck.
![:blush: :blush:](/media/kunena/emoticons/blush.png)
The machine is fitted with servo motors complete with controllers which have speed/direction input +/-10V.
Feedback is given by incremental encoders attached directly to the motors, 500pulses/rev.
Is a PC with 1/2 parports sufficient? Do I need additional hardware?
Any help is appreciated
![:) :)](/media/kunena/emoticons/smile.png)
Thanks!
Please Log in or Create an account to join the conversation.
29 Mar 2014 20:56 #45373
by emcPT
Replied by emcPT on topic 3axis CNC retrofitting with LinuxCNC
Hello.
For the analog output that you require, you will need (most easy and effective approach) a board that will process the linuxcnc speed command to the analog voltage that will connect to your drives.
I sell a type of those boards (Mesa brand). Others boards are also available, like those from Pico systems that I have no direct experience.
The most popular product that I sell to achieve what you need is a combination of a 5i25 + 7i77. It also have several inputs and outputs that generally are enough to run a complete machine. I have stock in Europe and you can find my web site in www.eusurplus.com.
For the analog output that you require, you will need (most easy and effective approach) a board that will process the linuxcnc speed command to the analog voltage that will connect to your drives.
I sell a type of those boards (Mesa brand). Others boards are also available, like those from Pico systems that I have no direct experience.
The most popular product that I sell to achieve what you need is a combination of a 5i25 + 7i77. It also have several inputs and outputs that generally are enough to run a complete machine. I have stock in Europe and you can find my web site in www.eusurplus.com.
The following user(s) said Thank You: terans1085
Please Log in or Create an account to join the conversation.
29 Mar 2014 21:04 #45374
by ArcEye
Replied by ArcEye on topic 3axis CNC retrofitting with LinuxCNC
Hi
Have a look at these
www.mesanet.com/pdf/parallel/5i25man.pdf
www.mesanet.com/pdf/parallel/7i77man.pdf
Argh, emcPT types faster!
regards
Have a look at these
www.mesanet.com/pdf/parallel/5i25man.pdf
www.mesanet.com/pdf/parallel/7i77man.pdf
Argh, emcPT types faster!
regards
The following user(s) said Thank You: terans1085
Please Log in or Create an account to join the conversation.
30 Mar 2014 03:33 - 31 Mar 2014 02:38 #45384
by jmelson
which is a set of boards to control the servo amps, read encoder position and handle digital I/O.
It may look more expensive than the Mesa boards, but is an all-in-one package which doesn't
require a number of additional parts to complete the interface.
The basic 4-axis package is US $780.
See pico-systems.com/osc2.5/catalog/index.php?cPath=1
Jon
Replied by jmelson on topic 3axis CNC retrofitting with LinuxCNC
Another option for analog velocity servo interfacing is the Pico Systems PPMC (Parallel Port Motion Control)
I am in the process of retrofitting LinuCNC on an old 3axis woodworking cnc router, however, this being my first time, (both at CNC, and at Linux) I got stuck.
The machine is fitted with servo motors complete with controllers which have speed/direction input +/-10V.
Feedback is given by incremental encoders attached directly to the motors, 500pulses/rev.
which is a set of boards to control the servo amps, read encoder position and handle digital I/O.
It may look more expensive than the Mesa boards, but is an all-in-one package which doesn't
require a number of additional parts to complete the interface.
The basic 4-axis package is US $780.
See pico-systems.com/osc2.5/catalog/index.php?cPath=1
Jon
Last edit: 31 Mar 2014 02:38 by jmelson.
The following user(s) said Thank You: terans1085
Please Log in or Create an account to join the conversation.
- terans1085
-
Topic Author
- Offline
- Junior Member
-
Less
More
- Posts: 38
- Thank you received: 0
30 Mar 2014 05:56 #45392
by terans1085
Replied by terans1085 on topic 3axis CNC retrofitting with LinuxCNC
Thank you for your replies!
I was looking into the MESA option, and was wondering:
What about using just the 5i25, employing two PWM outputs per servo (forward & reverse), low pass filtered to create an analog signal, into an opamp to amlify to 10V max? In theory then each channel can be fed into the differential inputs of the servo driver to allow forward/reverse control.
Would LinuxCNC support such output? Any problems you can think of of using such setup?
thanks & Regards,
I was looking into the MESA option, and was wondering:
What about using just the 5i25, employing two PWM outputs per servo (forward & reverse), low pass filtered to create an analog signal, into an opamp to amlify to 10V max? In theory then each channel can be fed into the differential inputs of the servo driver to allow forward/reverse control.
Would LinuxCNC support such output? Any problems you can think of of using such setup?
thanks & Regards,
Please Log in or Create an account to join the conversation.
30 Mar 2014 23:28 #45421
by PCW
Replied by PCW on topic 3axis CNC retrofitting with LinuxCNC
You can certainly do that. We use that method on the 7I33 and 7I48 interface cards
note that to be accurate and fast is a bit trickier, we use:
FPGA PWM --> cable
--> cable impedance matched termination
--> fast CMOS buffer powered by accurate reference voltage
--> passive LP filter (to avoid slew limit problems of active filter)
--> multipole active filter/level shift
note that to be accurate and fast is a bit trickier, we use:
FPGA PWM --> cable
--> cable impedance matched termination
--> fast CMOS buffer powered by accurate reference voltage
--> passive LP filter (to avoid slew limit problems of active filter)
--> multipole active filter/level shift
The following user(s) said Thank You: terans1085
Please Log in or Create an account to join the conversation.
- terans1085
-
Topic Author
- Offline
- Junior Member
-
Less
More
- Posts: 38
- Thank you received: 0
22 Apr 2014 20:01 #46213
by terans1085
Replied by terans1085 on topic 3axis CNC retrofitting with LinuxCNC
Hi,
I have acquired Mesa's 5i25 and 7i77 and hooked the drives up. Currently in the process of tuning PID.
Focusing just on X-axis, this is what I've learned so far:
Any tips on what and what not to do?
Thanks and Regards,
I have acquired Mesa's 5i25 and 7i77 and hooked the drives up. Currently in the process of tuning PID.
Focusing just on X-axis, this is what I've learned so far:
- Increasing P more than 10 makes the drive makes a loud noise
- Increasing I to about 20 reduces following error, but only up to about 0.5mm. Further increasing has no visible effect.
- Increasing D to 1 makes the motor make a very loud vibrating noise.
Any tips on what and what not to do?
Thanks and Regards,
Please Log in or Create an account to join the conversation.
22 Apr 2014 20:21 #46216
by andypugh
A D of one is very large indeed. Try 0.0001 and increase from there.
With the right amount of D you should find that you can increase P.
How many encoder counts is 0.5mm?
Replied by andypugh on topic 3axis CNC retrofitting with LinuxCNC
Increasing P more than 10 makes the drive makes a loud noise Increasing I to about 20 reduces following error, but only up to about 0.5mm. Further increasing has no visible effect. Increasing D to 1 makes the motor make a very loud vibrating noise.
A D of one is very large indeed. Try 0.0001 and increase from there.
With the right amount of D you should find that you can increase P.
How many encoder counts is 0.5mm?
The following user(s) said Thank You: terans1085
Please Log in or Create an account to join the conversation.
22 Apr 2014 20:21 #46217
by PCW
Replied by PCW on topic 3axis CNC retrofitting with LinuxCNC
if you have velocity mode drives,
gnipsel.com/linuxcnc/tuning/servo.html
is a good tuning tutorial.
Note that you should have no I or D when doing the preliminary tuning
gnipsel.com/linuxcnc/tuning/servo.html
is a good tuning tutorial.
Note that you should have no I or D when doing the preliminary tuning
Please Log in or Create an account to join the conversation.
- terans1085
-
Topic Author
- Offline
- Junior Member
-
Less
More
- Posts: 38
- Thank you received: 0
22 Apr 2014 22:06 #46222
by terans1085
Replied by terans1085 on topic 3axis CNC retrofitting with LinuxCNC
X axis has 160 encoder pulses / mm so 0.5mm is a lot of pulses of following error.
PCW: I shall be trying this method and keep you posted
Thanks!
PCW: I shall be trying this method and keep you posted
Thanks!
Please Log in or Create an account to join the conversation.
Time to create page: 0.118 seconds