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7I90HD with Raspberry pi and getting weird joint 0 following errors
23 Feb 2021 16:29 #199847
by creisey
Hi i have a question i have a XXYZ config
the attached one is working without the error, but the homing takes forever
as long as i have MAX_VELOCITY & MAX_ACCELERATION in the Joint section the homing is quick as usual but after some movements i run in a joint error. > check example below
the attached one is working without the error, but the homing takes forever
[AXIS_X]
MAX_VELOCITY = 200
MAX_ACCELERATION = 300
MIN_LIMIT = -9999.0
MAX_LIMIT = 9999.0
[JOINT_0]
TYPE = LINEAR
# Set Stepgen max 20% higher than the axis
STEPGEN_MAXVEL = 250
STEPGEN_MAXACCEL = 375as long as i have MAX_VELOCITY & MAX_ACCELERATION in the Joint section the homing is quick as usual but after some movements i run in a joint error. > check example below
[AXIS_X]
MAX_VELOCITY = 200
MAX_ACCELERATION = 300
MIN_LIMIT = -9999.0
MAX_LIMIT = 9999.0
[attachment=35102]iosi.hal[/attachment] [attachment=35103]iosi.ini[/attachment]
[JOINT_0]
TYPE = LINEAR
MAX_VELOCITY = 200
MAX_ACCELERATION = 300
# Set Stepgen max 20% higher than the axis
STEPGEN_MAXVEL = 250
STEPGEN_MAXACCEL = 375Please Log in or Create an account to join the conversation.
23 Feb 2021 16:34 #199848
by Aciera
Replied by Aciera on topic 7I90HD with Raspberry pi and getting weird joint 0 following errors
Note that your STEPGEN_MAXVEL is actually more than "20%" higher than the axis.
So maybe try reducing that bit.
So maybe try reducing that bit.
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23 Feb 2021 16:41 - 23 Feb 2021 16:42 #199850
by creisey
Replied by creisey on topic 7I90HD with Raspberry pi and getting weird joint 0 following errors
i tried that with 20% as well. same effect...
funny thing is there are examples with 20% and 25%
funny thing is there are examples with 20% and 25%
# The values below should be 25% larger than MAX_VELOCITY and
MAX_ACCELERATION
Last edit: 23 Feb 2021 16:42 by creisey.
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23 Feb 2021 16:44 #199852
by Clive S
Replied by Clive S on topic 7I90HD with Raspberry pi and getting weird joint 0 following errors
Re this:-
HOME = 0.000
HOME_OFFSET = 0.0
HOME_SEARCH_VEL = -10 This is the speed it will search for the home switch
HOME_LATCH_VEL = 2.5
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = YES
HOME_SEQUENCE = 2 if you want gantry squaring this has to be a -ve number
# these are in nanoseconds
DIRSETUP = 2500
DIRHOLD = 2500
STEPLEN = 2500 might have to increase these
STEPSPACE = 2500
HOME = 0.000
HOME_OFFSET = 0.0
HOME_SEARCH_VEL = -10 This is the speed it will search for the home switch
HOME_LATCH_VEL = 2.5
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = YES
HOME_SEQUENCE = 2 if you want gantry squaring this has to be a -ve number
# these are in nanoseconds
DIRSETUP = 2500
DIRHOLD = 2500
STEPLEN = 2500 might have to increase these
STEPSPACE = 2500
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23 Feb 2021 16:53 #199856
by creisey
right those values are getting read while i set MAX_VELOCITY & MAX_ACCELERATION in the [JOINT_0] section, but if they are missing the search velocity is set to very slow value. after the slow homing process, jogging is working without the sudden following errors.
Replied by creisey on topic 7I90HD with Raspberry pi and getting weird joint 0 following errors
Clive S wrote: Re this:-
HOME = 0.000
HOME_OFFSET = 0.0
HOME_SEARCH_VEL = -10 This is the speed it will search for the home switch
HOME_LATCH_VEL = 2.5
HOME_USE_INDEX = NO
HOME_IGNORE_LIMITS = YES
HOME_SEQUENCE = 2 if you want gantry squaring this has to be a -ve number
# these are in nanoseconds
DIRSETUP = 2500
DIRHOLD = 2500
STEPLEN = 2500 might have to increase these
STEPSPACE = 2500
right those values are getting read while i set MAX_VELOCITY & MAX_ACCELERATION in the [JOINT_0] section, but if they are missing the search velocity is set to very slow value. after the slow homing process, jogging is working without the sudden following errors.
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23 Feb 2021 17:01 #199857
by Aciera
Replied by Aciera on topic 7I90HD with Raspberry pi and getting weird joint 0 following errors
Have you tried reducing velocity and acceleration by say 50% ?
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23 Feb 2021 17:15 #199861
by Clive S
Replied by Clive S on topic 7I90HD with Raspberry pi and getting weird joint 0 following errors
I only see one set of stepgens etc for the X motors in the hal file.
Are sending the output to 2 drives.
Are sending the output to 2 drives.
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23 Feb 2021 17:23 - 23 Feb 2021 17:26 #199863
by creisey
Replied by creisey on topic 7I90HD with Raspberry pi and getting weird joint 0 following errors
the hal-file is not properly commented.
stepgen.00 and stepgen.01 are my X-axis
i have tried also slower rates and they might work better, but i dont understand why the setup is working when "STEPGEN_MAXVEL & STEPGEN_MAXACCEL" is missing in the Joint section with the side-effect is a slow homing
stepgen.00 and stepgen.01 are my X-axis
i have tried also slower rates and they might work better, but i dont understand why the setup is working when "STEPGEN_MAXVEL & STEPGEN_MAXACCEL" is missing in the Joint section with the side-effect is a slow homing
Last edit: 23 Feb 2021 17:26 by creisey.
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23 Feb 2021 17:32 - 23 Feb 2021 17:33 #199864
by PCW
Replied by PCW on topic 7I90HD with Raspberry pi and getting weird joint 0 following errors
A couple of things:
With a 0.050 mm maximum following error, 250 usec of servo thread jitter will cause a
following error with your current setup . What is you servo thread jitter?
There are a couple of things that can be done to improve stepgen performance with regard to host jitter:
1. Use the stepgen in velocity mode and a PID loop to control the position (use a pncconf created hal/ini file set as a model)
2. Use the DPLL to reduce host servo thread jitter impact on position sampling errors
With a 0.050 mm maximum following error, 250 usec of servo thread jitter will cause a
following error with your current setup . What is you servo thread jitter?
There are a couple of things that can be done to improve stepgen performance with regard to host jitter:
1. Use the stepgen in velocity mode and a PID loop to control the position (use a pncconf created hal/ini file set as a model)
2. Use the DPLL to reduce host servo thread jitter impact on position sampling errors
Last edit: 23 Feb 2021 17:33 by PCW.
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23 Feb 2021 19:02 - 25 Feb 2021 08:02 #199878
by creisey
Replied by creisey on topic 7I90HD with Raspberry pi and getting weird joint 0 following errors
i set to FERROR = 0.08 and it works. thx a lot
and set MIN_FERROR = 0.02
and set MIN_FERROR = 0.02
Last edit: 25 Feb 2021 08:02 by creisey.
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