Reverse Z-Axis for Servo

More
7 years 4 months ago #135634 by HueyHQ
Reverse Z-Axis for Servo was created by HueyHQ
My retrofit Z-axis works correctly as originally intended, in that a positive movement is downwards into the material.

From what I've seen on this forum and in some post-processors, it seems the general practice is that positive movement should be upwards? This would also match the keyboard jog Pg-Up and Pg-Down.

I read somewhere that for a stepper, making the STEP_SCALE negative will do this, but what parameter do I change for a servo? I would prefer not to physically rewire the servo and encoder.

Also, I realise I will need to change my homing parameters polarity; do I need to switch my MIN_LIMIT and MAX_LIMIT accordingly (I'm guessing I do)?

Code:
#****************************************** [AXIS_Z] MAX_VELOCITY = 83.333333 MAX_ACCELERATION = 300.0 MIN_LIMIT = -1.0 MAX_LIMIT = 140.0 [JOINT_2] TYPE = LINEAR HOME = 0.0 FERROR = 10.0 MIN_FERROR = 1.0 MAX_VELOCITY = 83.333333 MAX_ACCELERATION = 300.0 P = 0.5 I = 0 D = 0 FF0 = 0 FF1 = 0.0585 FF2 = 0 BIAS = 0 DEADBAND = 1e-05 MAX_OUTPUT = 0 ENCODER_SCALE = 80 OUTPUT_SCALE = 10 OUTPUT_MIN_LIMIT = -10 OUTPUT_MAX_LIMIT = 10 MIN_LIMIT = -1.0 MAX_LIMIT = 140.0 HOME_OFFSET = 0.000000 HOME_SEARCH_VEL = -15 HOME_LATCH_VEL = 5 HOME_FINAL_VEL = 0.000000 HOME_USE_INDEX = YES HOME_SEQUENCE = 0 #******************************************

Please Log in to join the conversation.

More
7 years 4 months ago #135647 by pl7i92
Replied by pl7i92 on topic Reverse Z-Axis for Servo
Change
ENCODER_SCALE = 101981
OUTPUT_SCALE = 10.0

to
ENCODER_SCALE = -101981
OUTPUT_SCALE = -10.0

Please Log in to join the conversation.

More
7 years 4 months ago #135689 by HueyHQ
Replied by HueyHQ on topic Reverse Z-Axis for Servo
Seems simple enough; I'll give it go, and work out the other stuff as I go.
Thanks.

Please Log in to join the conversation.

More
7 years 4 months ago #135706 by andypugh
Replied by andypugh on topic Reverse Z-Axis for Servo
You probably also want the top of travel to be machine zero, and the Z to run from zero downwards as negative numbers.
In principle this shouldn't matter, except that many CAM systems assume that a G53 G0 Z0 is a good and safe thing to do at the beginning of a programme.
(and that assumption has cost at least one builder here a brand-new spindle :-(

Please Log in to join the conversation.

More
7 years 4 months ago #135710 by pl7i92
Replied by pl7i92 on topic Reverse Z-Axis for Servo
if it is not only your mashine
it is better to get a wirer change to the ISO coordinate movement on machine Power

Please Log in to join the conversation.

More
7 years 4 months ago #135717 by HueyHQ
Replied by HueyHQ on topic Reverse Z-Axis for Servo

andypugh wrote: (and that assumption has cost at least one builder here a brand-new spindle :-(

I read that. Which is when I decided it was a good idea to ask the question, and not risk the same fate.

Please Log in to join the conversation.

More
7 years 4 months ago #135719 by pl7i92
Replied by pl7i92 on topic Reverse Z-Axis for Servo
trixing on cable wire ring is always not a good idee as it is software bahavior even if you need 2days to change swap 2 wirers it is the best way to go

Please Log in to join the conversation.

Time to create page: 0.121 seconds
Powered by Kunena Forum