Plasmac z axis touch n go

hello everyone i am fiddeling a while on plasmac, and this problem i was not able to figure out.

1. homimg all axes
2. jogging z just below the lowest slat
3. zeroing z axis
4. homing z
5. probe testing
a. torch moves down
b. hits the material to cut
c.z axis carriage moves further towards material to cut
d. proximity sensor recognizes passing carriage, and keeps moving after the trip point until, i guess, the probe height specified in config is reached, then it sits there without moving up until the button timeout occurs and moves back to home position
e. tripping of prox. Sensor can be seen in plasmac float switch indicator light
6. when proximity sensor is triggered a second time e.g. with a screwdriver while it sits on the surface“wating for the time out“ it moves further down and error messages get displayed that soft limits are exedeed


any idea what to change?

Best
Ben

ini from z axis

[AXIS_Z]
# set to double the value in the corresponding joint
MAX_VELOCITY = 100.0
# set to double the value in the corresponding joint
MAX_ACCELERATION = 1500.0
# shares the above two equally between the joint and the offset
OFFSET_AV_RATIO = 0.5
MIN_LIMIT = -60.0001
MAX_LIMIT = -15.0001

[JOINT_2]
TYPE = LINEAR
HOME = -58.00
MIN_LIMIT = -60.0001
MAX_LIMIT = -15.0001
MAX_VELOCITY = 50.0
MAX_ACCELERATION = 750.0
STEPGEN_MAXACCEL = 937.5
SCALE = 50.0
FERROR = 1
MIN_FERROR = .25
HOME_OFFSET = -47.00
HOME_SEARCH_VEL = -40.00000
HOME_LATCH_VEL = 10.00000
HOME_SEQUENCE = 0

i was thinking, maybe its the switch debounce wich smoothes the signal from the first trip to much? ill try and remove the debounce tomorrow and report back.

Home should be near the top of travel, so something like -16 rather than -58.

Can you compress the config directory and post it.

Hello Phil,

attached the config.

"Home should be near the top of travel, so something like -16 rather than -58."

the torch tip would be way below the slats so i made the travel max -60, then home -58 and minimum travel -15, this is where the torch tip is below the slats. so the farthest point away from the slats is -60.

yesterday evening i changed the z coordinate system into positive hoping it helps but it didnt. So dont wonder if the .ini entries for z now look different. from yesterdays post


Ben

edit:
i made the following observation, z axis is at home position 25mm, i set the probing height to 5mm, z axis drives to 5mm mark and then sits there until time out and drives back up. only when i set the probing height to a travel value where the float switch is triggerd the axis goes into probing speed but drives until end of minimum travel, waits for time out and retracts,

Max limit needs to be greater than Min Limit, if you want your Max Limit to be -60, then you min limit would need to be -105.

I would stick to the 0.0001 and 45.0001 you have in the posted plasmav1.ini, to me it is easier to comprehend.

Does the z axis move up when you jog with the + button?

Where is your home switch in relation to the max limit?

Hello Phil,

z axis goes down, towards slats when pressing +,the home switch is close to max limit.

...now i inverted the hal pin so that when pressing + the axis moves up, changed the sign of home search vel and changed the home offset that the axis can be homed proper and now by pressing probe test the axis doesent move anymore but homing and jogging works.

[AXIS_Z]
# set to double the value in the corresponding joint
MAX_VELOCITY = 100.0
# set to double the value in the corresponding joint
MAX_ACCELERATION = 400.0
# shares the above two equally between the joint and the offset
OFFSET_AV_RATIO = 0.5
MAX_LIMIT = 45.000
MIN_LIMIT = 0.000


[JOINT_2]
TYPE = LINEAR
HOME = 44.00
MIN_LIMIT = 0.000
MAX_LIMIT = 45.000
MAX_VELOCITY = 50.0
MAX_ACCELERATION = 200.0
STEPGEN_MAXACCEL = 937.5
SCALE = 50.0
FERROR = 1
MIN_FERROR = .25
HOME_OFFSET = 45.00
HOME_SEARCH_VEL = 40.00000
HOME_LATCH_VEL = 10.00000
HOME_SEQUENCE = 0

benbenben wrote:

.now i inverted the hal pin

which HAL pin?

Is the move up/down signal during probing controlled by the z direction/pulse pins or by the up/down pins defined in the configurator for THC?

It is done internally by usin offsets.


Your home offset and home would then need to be close to 45

which HAL pin?

Inverted the z direction pin, so that when pressing + the axis moves up. Right now I am not on the machine but what's bugging me is, that that was probably a mistake, instead of inverting the pin to move the z axis up when pressing +, I should have modified the z parameter for home, home offset and home search vel. That this fixes the movement. What I observed is, the z axis is not moving down on probing when the probe height is set to the maximum z hight. When I move the z axis down a bit and hit probing the z axis moves up. So i guess the error is in the setup of my home, homeoffset and home search vel and latching direction

The ways to reverse motor direction are:
1. reverse either of the two motor coils, but only one coil not both.
2. change the sign of the SCALE for that joint in the ini file, so if the scale was 50 make it -50

changing the scale is the way I normally do it

Thank you Phil,

I am away for 2 weeks now, when I am back. I test it out and report back.