How to. 2 or more motors on one axis. Gantry LinuxCNC 2.8 Master

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30 Sep 2019 12:08 #146707 by tommylight
You have them set as two separate axis, they should be the same axis but with two joints.
Attach the hal and ini files.

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30 Sep 2019 13:41 #146709 by pl7i92
i guess you will use gantryhoming
[KINS]
KINEMATICS = trivkins coordinates=XYYZ kinstype=BOTH
JOINTS = 4
## so joint0=X joint1=yA joinit2=yB joint3=Z
[JOINT_1]
TYPE = LINEAR
# final home position machine-unit/sec
HOME = 70 #where the mashine ends after homing is finished
MIN_LIMIT = -0.001
MAX_LIMIT = 200
MAX_VELOCITY = 25.0
MAX_ACCELERATION = 750.0
STEPGEN_MAXACCEL = 937.5
SCALE = 200
FERROR = 1
MIN_FERROR = .25
# FIRST MOTOR OFSET TO BE SQARE
# use this to square the gantry
HOME_OFFSET = 0.1

# machine-units per sec next 3 lines
HOME_SEARCH_VEL = 10
HOME_LATCH_VEL = -6
HOME_FINAL_VEL = 20

HOME_USE_INDEX = NO
# has to be -ve for gantry
HOME_SEQUENCE = -1

[JOINT_2]
TYPE = LINEAR
# final home position machine-unit/sec
HOME = 70
MIN_LIMIT = -0.001
MAX_LIMIT = 200
MAX_VELOCITY = 25.0
MAX_ACCELERATION = 750.0
STEPGEN_MAXACCEL = 937.5
SCALE = 200
FERROR = 1
MIN_FERROR = .25
# second SIDE ofset to be square 
# use this to square the gantry
HOME_OFFSET = 0.5

# machine-units per sec next 3 lines
HOME_SEARCH_VEL = 10
HOME_LATCH_VEL = -6
HOME_FINAL_VEL = 20

HOME_USE_INDEX = NO
# has to be -ve for gantry
HOME_SEQUENCE = -1


the AXis Y will travel both till the first reatch A switch then it will be homing one after the other and then travel to HOME on Both

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01 Oct 2019 09:07 - 01 Oct 2019 09:09 #146791 by deemoss
Thanks Guys!

I (kind of) fixed it after reading your comments by adding the second Y to:
[TRAJ]
COORDINATES = X Y Y Z

Now when I go to Machine -> Homing i don't see the Y axis (is this correct?) see screenshot homing.png.

Also, after I do Home ALL (actually that does not include homing Z because I have no sensors on it - #HOME_SEQUENCE is commented out) and then try to jog Y, I get this error which refers to joint1 (part of axis Y) not being homed. The strange thing is that I can jog Y after I Touch Off Z. Screenshot Moving Y-after homing ALL.png.

I also attached my INI and HAL files.

Dimos
Attachments:
Last edit: 01 Oct 2019 09:09 by deemoss.

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01 Oct 2019 13:04 #146802 by dgarrett
If HOME_SEQUENCE is not specified then the joint
will not be homed by the HOME ALL sequence (but may be
homed by individual joint-specific homing commands).

Ref: linuxcnc.org/docs/2.8/html/config/ini-homing.html
Specifically:
Ref: linuxcnc.org/docs/2.8/html/config/ini-ho....html#_home_sequence

Use "Immediate homing" for the joint that
corresponds to the Z coordinate (joint 2 in your case)
if it has no home switches
Immediate Homing

If a joint does not have home switches or does not have
a logical home position like a rotary joint and you
want that joint to home at the current position when
the "Home All" button is pressed in the Axis gui, then
the following ini entries for that joint are needed.

    HOME_SEARCH_VEL = 0
    HOME_LATCH_VEL = 0
    HOME_USE_INDEX = NO
    HOME equals to HOME_OFFSET
    HOME_SEQUENCE = 0 (or other valid sequence number)

Ref: linuxcnc.org/docs/2.8/html/config/ini-ho...ml#_immediate_homing

When using trivkins for a gantry with two joints for a
coordinant, it is recommended to use kinstype=Both in
order to see the homing condition for each joint.

The attached ini file is a sim config based on your ini
file for demonstration (it is a simulation, no hardware
required):
Attachments:
The following user(s) said Thank You: deemoss

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01 Oct 2019 13:35 #146806 by pl7i92
the Z limit woudt be the one needed most
sa it is for Toolmesure workpice mesure against the Mashine coordinate system
youshoudt realy have there one
The following user(s) said Thank You: deemoss

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