I just finished converting a PM833 to CNC. I homed the machine a dozen times... No problem. I ran some test gcode (see attached file "Circular pocket"), no problem. I ran the same gcode again today and as the program prompted for the 1st tool change, and the z-axis moved up to the proximity switch(see attached), it over-ran the limit switch slightly and cracked the limit switch mounting bracket. I have also attached the recent report with all the settings.
Any idea as to why it overran the limit switch just enough to crack the bracket?
Thanks... Richard
Z-Axis Gone Too Far
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Z-Axis Gone Too Far
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- Circler pocket.cnc
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Re: Z-Axis Gone Too Far
Well, according to your report, those are home switches and not limit switches, so they would not have stopped movement anyway. Home switches are only active during the homing cycle.
If you do not have limit switches, then you need to be using soft limits which you also do not have configured.
If you do not have limit switches, then you need to be using soft limits which you also do not have configured.
Cheers,
Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
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Re: Z-Axis Gone Too Far
Tom, thanks for your quick response.
I am a bit confused. When I setup the homing details, I entered the software travel limits (see attached). What are my missing here?
Thanks... Richard
I am a bit confused. When I setup the homing details, I entered the software travel limits (see attached). What are my missing here?
Thanks... Richard
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Re: Z-Axis Gone Too Far
0 is not used as a limit, use 0.1 or set up the home switches as ..HomeLimitOk
At the time the overriding occurs you have had lots of resends, maybe a cause for the problem also.
Uwe
At the time the overriding occurs you have had lots of resends, maybe a cause for the problem also.
Uwe
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Re: Z-Axis Gone Too Far
Presumably your machine would have to decelerate down from your rapid speed in anticipation of stopping before over running the Z0 position. If the accel / decel values for your Z axis are not appropriate, I guess this could be an outcome. But as Uwe says, you should set a soft limit before the home position, to give yourself some margin.
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Re: Z-Axis Gone Too Far
Thanks for all your responses! I am sorry but I am still missing something.
I understand that I need to add a soft limit to give the machine some margin, but I am unclear as to where to add these numbers. The manual mentions a figure between .1 and .38 as Uwe noted, but where do I enter these numbers into the software? Should I be entering ".1" instead of "0" in the highlighted boxes on the attached?
Lastly, the proximity sensors are currently wired to an input configured as "Home All". I am not seeing the ability to define the input as "HomeLimitOk" that Uwe noted. What is difference between "Home All" and "HomeLimtOk"
Thanks... Richard
I understand that I need to add a soft limit to give the machine some margin, but I am unclear as to where to add these numbers. The manual mentions a figure between .1 and .38 as Uwe noted, but where do I enter these numbers into the software? Should I be entering ".1" instead of "0" in the highlighted boxes on the attached?
Lastly, the proximity sensors are currently wired to an input configured as "Home All". I am not seeing the ability to define the input as "HomeLimitOk" that Uwe noted. What is difference between "Home All" and "HomeLimtOk"
Thanks... Richard
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Re: Z-Axis Gone Too Far
(Axis)HomeLimitOk is only if you have one input per axis, but you can use HomeAll and LimitAll
0 is ignored as Limit, so you have to use an other value as limit, or limit sensors if you want to use 0 on one end of axis travel.
Try out to drive slowly to each axis end, if configured ok you will get an axis travel limit message.
Uwe
0 is ignored as Limit, so you have to use an other value as limit, or limit sensors if you want to use 0 on one end of axis travel.
Try out to drive slowly to each axis end, if configured ok you will get an axis travel limit message.
Uwe
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Re: Z-Axis Gone Too Far - SOLVED
Ok. I added the limits show on the attached. I am now getting errors when I instruct the machine to go beyond the limits. Thanks for all your help!
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Re: Z-Axis Gone Too Far
I was under the assumption that travel limit values were ignored if BOTH values were zero. I could be wrong
You are getting errors because your negative homing axes (M91) travel limits must be zero or positive. Positive homing axes (M92) must be zero or negative
You are getting errors because your negative homing axes (M91) travel limits must be zero or positive. Positive homing axes (M92) must be zero or negative
Re: Z-Axis Gone Too Far
Gary is right: as long as at least one of the travel limits for an axis is non-zero, then soft limits are active. There is no problem with having a plus limit of 0.0 and a minus limit of, for example, -23.6.
Soft limits only apply after the axis has been homed.
Soft limits only apply after the axis has been homed.