Renishaw Linear Encoders, EMC2 and Mesa 5120

More
05 Feb 2010 00:29 #1752 by Hobbydad
Hello!

I am wanting to use Renishaw Linear Encoders with a Mesa 5120 controller card, is this possible and does EMC2 support linear encoders. Also does EMC2 and Mesa 5120 support switches(out of range) for x,y & z incase the machine just takes off?

Thanks,
Hobbydad

Please Log in or Create an account to join the conversation.

More
05 Feb 2010 01:53 #1754 by cmorley
Short answer : yes yes and yes
I assume the encoders output square wave signals. Mesa can count them
You can use linear scales with EMC . Whether thats a good idea depends what you are doing.
Steppers? servos? Only using linear scales with servos might not work that well , better is to use rotary encoder on the motor or ball screws and
optionally linear scales on the slides. The problem with just using linear scales is the EMC can't tell when the motor is moving when there is backlash
and thats screws with the tuning.
With steppers EMC can use the scales to monitor if a real following error has happenned.
see here:
wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Steppers_With_Encoders

EMC supports real limit switches and software limits. If using servos with PID control you can also have EMC monitor the output of the PID and if it saturates (at maximum output) for too long throws an Estop.

Please Log in or Create an account to join the conversation.

More
05 Feb 2010 02:09 #1755 by Hobbydad
Yes encoders are square wave! I am using slides for the xyz travel. As far as I know these are servos, the reason I guess was the machine I'm converting over was very precise with it's movement down to microns. I haven't tore into the drives or evn where they are at but they would seem small in size.

Any suggestions on steppers if I wanted to change it over?

Thanks,
Hobbydad

Please Log in or Create an account to join the conversation.

More
05 Feb 2010 02:53 #1757 by PCW
If you have low backlash you may get away with using the linear encoders without any rotary encoders on the motor
We have had customers this setup that were able to get good performance. Having velocity mode amplifiers will help.

If the existing motors and drives work changing to step motors would be a _step_ down...

Please Log in or Create an account to join the conversation.

More
08 Feb 2010 00:53 #1808 by Hobbydad
Good that's what I wanted to hear that it would proubably work ok. The amps are Allen Bradley and they do support different modes.

Cmorley,

I downloaded GCAM but I can't find it on my computer anywhere. When I try to reinstall it says that it is there. Now granted i'm not 100% of a linux user yet and maybe i'm overlooking where it is at. I am using Ubuntu 8.04 Hardy Heron rel. April 2008. maybe there is a version conflict don't know!

Thanks,
Hobbydad

Please Log in or Create an account to join the conversation.

Time to create page: 0.083 seconds
Powered by Kunena Forum