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JSON-Format $hom Query?

From the original Synthetos forum (2011–2025)

Started by Chris S on in TinyG Support. 3 replies, last activity Feb 4, 2019.

Chris S #

I have questions about this:

Once the latch backoff is complete the axis moves further off the switch by the Zero Backoff amount and sets zero for that axis. The axis is marked as HOMED in the homing state variable ($homx, where 'x' is any axis).

Once all axes are processed the affected axes will be at the absolute home location (machine zero).

At this point the global homing state ($home) will indicate that the machine has been homed. Homing state can be read for global, and for each axis ($homx, $homy...), or all together using the homing group: $hom. This returns 0 or 1 for each axis to indicate homing state for each axis and the global homing state.

1. This seems to not be true: "This returns 0 or 1 for each axis to indicate homing state..."

This is the return from '$hom':

Homing state: Homed
X position: 1.000 mm
Y position: 1.000 mm
Z position: 1.000 mm
A position: 0.000 deg
B position: 0.000 deg
C position: 0.000 deg

Have I done something incorrectly?

2. Is there a JSON-formatted version of '$hom'? I see nothing in the documentation here: https://github.com/synthetos/TinyG/wiki/Homing-and-Limits-Description-and-Operation

Thanks guys, I appreciate the support.

cmcgrath5035Staff #

I believe I have seen information that says one needs to read
1.000 mm as Logical 1, yes, the axis is homed.

Need to dig a bit.

Json - I don't believe there is, more dig

Chris S #

Regarding 1.00 = '1', I understand. Thanks.

{“gc”:”G28.2X0Y0″} executes the homing sequence. I guess it would be helpful if I explained what I'm trying to accomplish and why...

I have some systems deployed, temporarily, in a high-ESD environment. While I've taken every precaution I can (treating the floor and furniture with anti-static spray works surprisingly well, instituted ESD safety rules like smocks and ground straps) it's been proven inevitable that people are going to shock these machines. When that happens the TinyG resets and my GCode administrator keeps sending commands because it doesn't detect any error. This often leads to crashes.

I've determined that when this reset event occurs the $hom bit is set to FALSE (0). What I'd like to do is be able to query this bit between commands to detect that an error has occurred.

Or something with the same result that tells me the thing has lost its mind.

Thanks.

PS - ideally I'd fix the underlying problem but right now I have no choice but to keep the machines where they are.

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