End stop questions
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Hi,
I'm sure this has been asked before but I'm struggling to find it using the search.I have 3 questions regarding end-stops :
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How do i enable them to actually stop movement when triggered? On my duet2Wifi printer, they are used for homing, but if the printer ever has a problem and misses steps, it will happily crash into the end stops and continue trying even though they're triggering. It's not an issue on the printer since the frames sturdy enough, but with the cnc, I'll end up putting a lot of force in places I don't want.
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How do I enable endstops for both ends of the axis? I'm in the RRF config tool and it only gives the option for a single endstop per axis. Is this something I need to do afterwards in the config file?
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I have end stops that will be active low (not voltage specific), in this case, would I just use the 3.3v and Io.In pin?
Many thanks in advance!
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@Asdasd1234 said in End stop questions:
How do i enable them to actually stop movement when triggered? On my duet2Wifi printer, they are used for homing, but if the printer ever has a problem and misses steps, it will happily crash into the end stops and continue trying even though they're triggering. It's not an issue on the printer since the frames sturdy enough, but with the cnc, I'll end up putting a lot of force in places I don't want.
After homing the firmware should respect the soft limits imposed by M208. If you need the end stops to trigger an e-stop look at making a trigger for them. https://duet3d.dozuki.com/Wiki/Gcode#Section_M581_Configure_external_trigger
How do I enable endstops for both ends of the axis? I'm in the RRF config tool and it only gives the option for a single endstop per axis. Is this something I need to do afterwards in the config file?
This wasn't supported in RRF2, but I think it is supported in RRF3, and you can configure them with https://duet3d.dozuki.com/Wiki/Gcode#Section_M574_Set_endstop_configuration
I have end stops that will be active low (not voltage specific), in this case, would I just use the 3.3v and Io.In pin?
I believe you'll need ground and Io.In. The Io.In pin will normally be pulled up, when the switch to ground closes it will be pulled low and asserted. (edit: If you're not using mechanical switches you may need to provide supply voltage as well as ground and the signal however)
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@bearer
Thanks for the response.For triggering an e-stop, it doesn't make clear on the link for M581 if it will disable the ability to use the pin for homing or not as
Looking at the M574 command, it doesn't imply that 2 per axis (each end of a single axis) is supported in rrf3 either.
I'd rather not have to fudge a workaround by putting them both in series or something to create the e-stop work both ends if at all possible. -
RRF3 doesn't (yet) support endstops at both ends of an axis. However, you can add a NC switch at the other end of each axis, wire these all in series, connect them to a spare input, and use them to trigger an emergency stop using M581.
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@Asdasd1234 said in End stop questions:
For triggering an e-stop, it doesn't make clear on the link for M581 if it will disable the ability to use the pin for homing or not as
the trigger is in addition to the homing function; the caveat is that you may have to disable the trigger at the start of the homing code, then re-enable it at the end of the homing code methinks.
as confirmed by dc42 the firmware support isn't done yet for multiples (i just haven't been paying close attention to the development lately). you should be able to wire them to individual inputs and create individual triggers if you don't want to wire them in series as a work around, however if you set the travel for the axis with M208 that should prevent you from hitting end of travel (assuming you don't override with G92 or loose steps or something else you would want to avoid in any case)
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No problem, I'll have 1 end-stop per axis setup as homing, and alter the homing routine to disable/enable the e-stop trigger, then the other 3 will be wired to a single io as a separate e-stop.
I know soft-limits should stop this, but I've got some pretty strong motors here more than capable of bending the frame out of square if I get any crashes, and during initial setup and testing, crashes are a big possibility.Many thanks all for the help
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@Asdasd1234 said in End stop questions:
during initial setup and testing, crashes are a big possibility.
Reduce motor currents during testing to reduce risk of damage. Same for during homing.
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@Phaedrux
Thats a good point, I will do that
