Please help me get this Homing Sequence Right
- eighthaxis
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14 May 2021 16:52 #208821
by eighthaxis
Please help me get this Homing Sequence Right was created by eighthaxis
I have been trying for 2 days to get this auto homing sequence right to no avail.
After reading this part of the manual as many times as I have I can almost recite it word for word yet I still can't get it right.
Pleas teach me almighty LinuxCNC Gurus!
My 5-Axis Machining Center is running a Mesa 7i77 and 5i25 with a mix of AC and DC Servos all with encoders
LinuxCnc 2.8
GMOCCAPY
All axis move in the proper direction when JOGGED Manually. All limits are on their own axis and respond correctly.
There is a limit switch on both ends of the travel of all Axis except for the A axis that uses only one since it can rotate continuously.
No individual Homing Switches just limit switches. I have tried almost every combination of settings for homing all resulting with different errors.
I am attaching my hal and ini files. Currently what happens with this particular config is that when I press Autohome in GMOCCAPY the X axis starts to move but when it hits the limit switch it just keeps on going! Nothing in GMOCCAPY saying it even hit the limit.
Yet if I just push the limit switch after powering on but before hitting the homing button it accurately show a error indicating the limit switch has been triggered.
If anyone can help me I would be very appreciative as I have already made it past the point of frustration right now.
Thanks
After reading this part of the manual as many times as I have I can almost recite it word for word yet I still can't get it right.
Pleas teach me almighty LinuxCNC Gurus!
My 5-Axis Machining Center is running a Mesa 7i77 and 5i25 with a mix of AC and DC Servos all with encoders
LinuxCnc 2.8
GMOCCAPY
All axis move in the proper direction when JOGGED Manually. All limits are on their own axis and respond correctly.
There is a limit switch on both ends of the travel of all Axis except for the A axis that uses only one since it can rotate continuously.
No individual Homing Switches just limit switches. I have tried almost every combination of settings for homing all resulting with different errors.
I am attaching my hal and ini files. Currently what happens with this particular config is that when I press Autohome in GMOCCAPY the X axis starts to move but when it hits the limit switch it just keeps on going! Nothing in GMOCCAPY saying it even hit the limit.
Yet if I just push the limit switch after powering on but before hitting the homing button it accurately show a error indicating the limit switch has been triggered.
If anyone can help me I would be very appreciative as I have already made it past the point of frustration right now.
Thanks
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14 May 2021 18:35 - 14 May 2021 18:40 #208835
by bevins
Replied by bevins on topic Please help me get this Homing Sequence Right
Did you read this?
HOME LATCH VELOCITY:
If HOME_SEARCH_VEL is zero (meaning there is no home switch), and this parameter is nonzero, LinuxCNC goes ahead to the index pulse search. If HOME_SEARCH_VEL is non-zero and this parameter is zero, it is an error and the homing operation will fail. The default value is zero.
Plus, I would put Z 1st then X and Y that way you move the Z out of he way of anything.
HOME LATCH VELOCITY:
If HOME_SEARCH_VEL is zero (meaning there is no home switch), and this parameter is nonzero, LinuxCNC goes ahead to the index pulse search. If HOME_SEARCH_VEL is non-zero and this parameter is zero, it is an error and the homing operation will fail. The default value is zero.
Plus, I would put Z 1st then X and Y that way you move the Z out of he way of anything.
Last edit: 14 May 2021 18:40 by bevins.
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14 May 2021 18:41 #208836
by chris@cnc
Replied by chris@cnc on topic Please help me get this Homing Sequence Right
First you need a reference switch or you take the z phase from the encoder. But keep in mind that wil find it with every Servo revolution
HOME_USE_INDEX = YES
For safe referencing, you need a switch from the zero point start searching.
Second, limit switch
switch on with -> HOME_IGNORE_LIMITS = NO
Third, set speed more than zero
HOME_SEARCH_VEL = 0
HOME_LATCH_VEL = 0
linuxcnc.org/docs/2.8/html/config/ini-homing.html
HOME_USE_INDEX = YES
For safe referencing, you need a switch from the zero point start searching.
Second, limit switch
switch on with -> HOME_IGNORE_LIMITS = NO
Third, set speed more than zero
HOME_SEARCH_VEL = 0
HOME_LATCH_VEL = 0
linuxcnc.org/docs/2.8/html/config/ini-homing.html
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- eighthaxis
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14 May 2021 19:14 #208839
by eighthaxis
Replied by eighthaxis on topic Please help me get this Homing Sequence Right
Thanks for your input Chris.
Here are the results and updated ini file.
It stops at the limit switch when homing the gives these errors:
joint 2 on limit switch error
hit limit in home state 7
Here are the results and updated ini file.
It stops at the limit switch when homing the gives these errors:
joint 2 on limit switch error
hit limit in home state 7
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14 May 2021 19:22 #208840
by eighthaxis
Replied by eighthaxis on topic Please help me get this Homing Sequence Right
Thanks for your reply but it is confusing.
Isn't this sentence contradicting itself?:
" If HOME_SEARCH_VEL is non-zero and this parameter is zero, it is an error and the homing operation will fail. "
There is no home switch only limit switches.
I changed Z to be first.
When the manual talks about index pulse is it referencing a special type of encoder that has an output index pulse at 0 degrees or one time per revolution or is it talking about the first pulse that the quadrature encoder gives out at the smallest amount of movement?
Isn't this sentence contradicting itself?:
" If HOME_SEARCH_VEL is non-zero and this parameter is zero, it is an error and the homing operation will fail. "
There is no home switch only limit switches.
I changed Z to be first.
When the manual talks about index pulse is it referencing a special type of encoder that has an output index pulse at 0 degrees or one time per revolution or is it talking about the first pulse that the quadrature encoder gives out at the smallest amount of movement?
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14 May 2021 19:24 - 14 May 2021 19:26 #208841
by Michael
Replied by Michael on topic Please help me get this Homing Sequence Right
Try
Home= 8.0
You may not have the joint 2 home position far enough away from the switch to deactivate it. The switch may have some throw you have to overcome before it senses as being off the switch. This setting should move the axis to the middle of it's travel after home.
During homing limit switches are not used (at least not as limits) and when the cycle completes, of the axis is still on the switch it will fault.
Also just noticed this:
HOME_IGNORE_LIMITS = NO
Needs to be yes since you are using the limit switch as home
Home= 8.0
You may not have the joint 2 home position far enough away from the switch to deactivate it. The switch may have some throw you have to overcome before it senses as being off the switch. This setting should move the axis to the middle of it's travel after home.
During homing limit switches are not used (at least not as limits) and when the cycle completes, of the axis is still on the switch it will fault.
Also just noticed this:
HOME_IGNORE_LIMITS = NO
Needs to be yes since you are using the limit switch as home
Last edit: 14 May 2021 19:26 by Michael.
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14 May 2021 19:27 #208842
by eighthaxis
Replied by eighthaxis on topic Please help me get this Homing Sequence Right
Doesen't this part of the manual say to set
HOME_IGNORE-LIMITS to YES if you are not using separate Home and Limit switches?
6.4. HOME_IGNORE_LIMITS
Can hold the values YES / NO. The default value for this parameter is NO. This flag determines whether LinuxCNC will ignore the limit switch input for this joint while homing. This setting will not ignore limit inputs for other joints. If you do not have a separate home switch set this to YES and connect the limit switch signal to the joint home switch input in HAL. LinuxCNC will ignore the limit switch input for this joint while homing. To use only one input for all homing and limits you will have to block the limit signals of the joints not homing in HAL and home one joint at a time.
HOME_IGNORE-LIMITS to YES if you are not using separate Home and Limit switches?
6.4. HOME_IGNORE_LIMITS
Can hold the values YES / NO. The default value for this parameter is NO. This flag determines whether LinuxCNC will ignore the limit switch input for this joint while homing. This setting will not ignore limit inputs for other joints. If you do not have a separate home switch set this to YES and connect the limit switch signal to the joint home switch input in HAL. LinuxCNC will ignore the limit switch input for this joint while homing. To use only one input for all homing and limits you will have to block the limit signals of the joints not homing in HAL and home one joint at a time.
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14 May 2021 19:32 #208845
by chris@cnc
Replied by chris@cnc on topic Please help me get this Homing Sequence Right
Now I'm confused too. Should the machine stop at the limit switch or not?
And index pulse = Z Phase encoder.
The zero mark on your encoder and there is only once per turn. Check in halshow
Is it also wired?
And index pulse = Z Phase encoder.
The zero mark on your encoder and there is only once per turn. Check in halshow
Is it also wired?
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14 May 2021 22:43 #208868
by eighthaxis
Replied by eighthaxis on topic Please help me get this Homing Sequence Right
Of course it should stop on the limit switch no one wants a crash.
So in halshow I watch: hm2_5i25.0.encoder.00.input-index
while manually jogging the axis and it just stays on a red indicator.
Do all encoders have this index mark?
So in halshow I watch: hm2_5i25.0.encoder.00.input-index
while manually jogging the axis and it just stays on a red indicator.
Do all encoders have this index mark?
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14 May 2021 23:05 - 14 May 2021 23:07 #208870
by Michael
Replied by Michael on topic Please help me get this Homing Sequence Right
Based on your first post it sounds like you do not have homing switches anywhere. Just limit switches on each end and you want to use one of the limit switches to home the machine. This is a perfectly fine setup but the limit switches need to be ignored during the homing process. Otherwise it will fault at the switch.
You only want to have that setting set to no if you have 3 switches per axis (for argument sake). If your axis setup looked like this:
Limit>>>>>>>>>home>>>>>>>>>limit
As for the index, depending on setup, the axis will go to home switch then go forward or backward (based on settings) to the next Z pulse. There is one z pulse per revolution.
You only want to have that setting set to no if you have 3 switches per axis (for argument sake). If your axis setup looked like this:
Limit>>>>>>>>>home>>>>>>>>>limit
As for the index, depending on setup, the axis will go to home switch then go forward or backward (based on settings) to the next Z pulse. There is one z pulse per revolution.
Last edit: 14 May 2021 23:07 by Michael.
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