Homing using limit and encoder index pulse?

[purple_jeep]

Hi,

Does anyone have any sample code showing how to use the limit switchs and encoder index pulse to generate an accurate home position?

Currently I have my limit switches set to kill drive I assume I need to change them to Dissalow drive into limit so I can run them to the limit then back off slowly until I see the encoder index pulse?

Cheers

Chris

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[TomKerekes]

Hi Chris,

To home to an index is pretty basic. It just involves an extra step after detecting the Limit to continue (or reverse) and wait for the index input.

I've attached a parameterized function that should do this. Add the function to your home.c program and call it specifying all the listed parameters.

HTH
Regards

[purple_jeep]

Hi Tom,

So
axis = 0 for x, 1 for y, 2 for z etc (if channel 0 is x axis etc)
speed = is in encoder counts per second? (encoder for position feedback)
dir = +1 or -1?
bit = 136 for first opto in? (do I remove the ! if my limits are active low?)
indexspeed = is in encoder counts per second? (encoder for position feedback)
indexbit = how do i reference this when it is connected to JP2 CHA_DIFFPLUS_4 etc?
Polarity = I dont see this used?
offset = is in encoder counts?

Cheers

Chris

[TomKerekes]

Hi Chris,

axis = 0 for x, 1 for y, 2 for z etc (if channel 0 is x axis etc)

yes

speed = is in encoder counts per second? (encoder for position feedback)

yes

dir = +1 or -1?

yes

bit = 136 for first opto in? (do I remove the ! if my limits are active low?)

yes, depends how it is wired

with the ! it reads "wait while bit is not true"
without the ! it reads "wait while bit is true"

try both ways

indexspeed = is in encoder counts per second? (encoder for position feedback)

yes

indexbit = how do i reference this when it is connected to JP2 CHA_DIFFPLUS_4 etc?

IO bit 36...43

Polarity = I don't see this used?

oops, see new attachment

offset = is in encoder counts?

yes

HTH
Regards