Inverting the Direction of a joint in Tandem Axis has no effect

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MartyJ
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11 May 2021 20:44 - 11 May 2021 20:51 #208581 by MartyJ

Inverting the Direction of a joint in Tandem Axis has no effect was created by MartyJ

Hello all,

I am setting up a XYYZ gantry machine. 5i25/single 7i76 setup driving Leadshine closed-loop stepper drivers.

I want to invert the direction of the tandem joint, in my case, that's stepgen 3, using:

setp   hm2_5i25.0.stepgen.03.direction.invert_output true

Because it's a closed-loop driver system, switching A+/A- wires will not work to invert the direction of the motor.
The stepscale is a positive value for both joints in this tandem axis.
There is no combination of stepscale sign or inverting stepgens 01 or 03 which result in stepgen 03 inverting its drection, even though I verify that the stepgen.03.direction.invert_output parameter is successfully registered as "true".

Any other ideas? Ini/HAL attached, thanks!

Last edit: 11 May 2021 20:51 by MartyJ.

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tommylight
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11 May 2021 21:55 #208587 by tommylight

Replied by tommylight on topic Inverting the Direction of a joint in Tandem Axis has no effect

The direction can be inverted by simply putting a - in front of the SCALE in the ini file, or removing it if there is already there.

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MartyJ
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11 May 2021 23:28 - 11 May 2021 23:30 #208599 by MartyJ

Replied by MartyJ on topic Inverting the Direction of a joint in Tandem Axis has no effect

Thanks! So I tried that, that's what "POS" and "NEG" mean in the STEPSCALE fields in the chart in my first post.

For my primary joint on stepgen 01, adding a - in front of the stepscale value reverses the direction of the motor. For the secondary stepgen, it does not.

Last edit: 11 May 2021 23:30 by MartyJ.

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PCW
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11 May 2021 23:29 #208600 by PCW

Replied by PCW on topic Inverting the Direction of a joint in Tandem Axis has no effect

Since stepgen 3 never changes direction, I would suspect a hardware problem

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MartyJ
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11 May 2021 23:31 #208601 by MartyJ

Replied by MartyJ on topic Inverting the Direction of a joint in Tandem Axis has no effect

Huh. I'll try hooking it up to stepgen 4 and see what happens, thanks for the idea.

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PCW
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11 May 2021 23:45 #208603 by PCW

Replied by PCW on topic Inverting the Direction of a joint in Tandem Axis has no effect

Might be drive wiring also

You can test the direction inversion with a voltmeter or just a
LED and halcmd

halcmd setp hm2_5i25.0.stepgen.03.direction.invert_output true
halcmd setp hm2_5i25.0.stepgen.03.direction.invert_output false

Should toggle the output polarities of the direction 3 outputs

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MartyJ
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11 May 2021 23:46 #208604 by MartyJ

Replied by MartyJ on topic Inverting the Direction of a joint in Tandem Axis has no effect

Bingo, thanks so much gents.

I'll buy a new 7i76, but for now moving to stepgen 4 has me up and running.

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andypugh
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12 May 2021 21:31 #208653 by andypugh

Replied by andypugh on topic Inverting the Direction of a joint in Tandem Axis has no effect

MartyJ wrote:
Bingo, thanks so much gents.
I'll buy a new 7i76, but for now moving to stepgen 4 has me up and running.

Could be wiring? Wire the wrong side of the cage clamp?

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MartyJ
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13 May 2021 01:01 - 13 May 2021 01:01 #208681 by MartyJ

Replied by MartyJ on topic Inverting the Direction of a joint in Tandem Axis has no effect

In the end (hopefully) it was EMF the whole time. I was using a non-shielded ribbon cable to connect the 5i25 to 7i76 inside my controller box, and it passed nearby my toroidal power supply. Now I'm using a different cable routing and shielded cable, hopefully sorted.

Last edit: 13 May 2021 01:01 by MartyJ.

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Inverting the Direction of a joint in Tandem Axis has no effect

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