Run Mesa 7i76e + 7i85 with 3 servos and 1 stepper motor

MarcusM
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14 Mar 2022 21:45 - 14 Mar 2022 21:47 #237242 by MarcusM

Run Mesa 7i76e + 7i85 with 3 servos and 1 stepper motor was created by MarcusM

Hi,

I run a 4-axis DIY milling machine with servo motors. In the moment, I try to put a carousel atc in service. The carousel (10 pockets) is driven by a closed loop stepper motor (stepper 60BYGH250D at leadshine CS-D508), not a servo. My first question: Is it possible to mix both servo and stepper motors controlled by one mesa 7i76e?

I use the probe_basic ui so I decided to try the carousel function from Andy Pugh (linuxcnc.org/docs/2.8/html/man/man9/carousel.9.html). Now I see in the manual, that there is required a minimum of 4 prox sensors. I only have one at the hardware (for homing), so I skip this idea. Or is it possible to use this function with a single prox sensor also?

Thanks & best regards
Marcus

PS: Please take my apologizes for my bad english - I'am from Germany :-)

Last edit: 14 Mar 2022 21:47 by MarcusM.

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tommylight
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14 Mar 2022 22:18 #237246 by tommylight

Replied by tommylight on topic Run Mesa 7i76e + 7i85 with 3 servos and 1 stepper motor

Hallo und wilkomen bei uns,
You can use servo and steppers and any combination of them. I am assuming you have the 3 servos running already, so just wire the closed loop stepper as a normal stepper, step/dir/ and enable if required/desired.
Also, pretty sure the Carousel component requires an index pin/sensor and another pin/sensor for pockets, Andy will know that best as he programmed that component.
MFG,
Tom.

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andypugh
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15 Mar 2022 18:51 #237359 by andypugh

Replied by andypugh on topic Run Mesa 7i76e + 7i85 with 3 servos and 1 stepper motor

Currently the carousel component does require a pulse-per-pocket.
I have had an email kept in my inbox since 6/21 to remind me to improve this. But so far have failed to do so.

The improvement would be to define a counts-per-pocket scale. This would work equally well for a stepper or an encoder.

How many step counts are there per pocket on your system? There might be a very simple answer if it is a multiple of two.

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MarcusM
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15 Mar 2022 22:59 #237403 by MarcusM

Replied by MarcusM on topic Run Mesa 7i76e + 7i85 with 3 servos and 1 stepper motor

Hi,

thanks a lot for the warm welcome :-)

And for your support.

This evening I put the stepper in work. Tomorrow I'll try to configure the homing sequence and figure out, how many steps are necessary to go from one pocket to another.

Best regards
Marcus

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MarcusM
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16 Mar 2022 20:26 #237491 by MarcusM

Replied by MarcusM on topic Run Mesa 7i76e + 7i85 with 3 servos and 1 stepper motor

Hi Andy,

the stepgen.04.counts value show -2003 after homing. After jogging to the next pocket the value is -1803, than -1603 and so one -> the difference between the pockets are 200 steps.

So, is there a chance to use the carousel method?

Best regards
Marcus

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andypugh
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17 Mar 2022 01:32 #237513 by andypugh

Replied by andypugh on topic Run Mesa 7i76e + 7i85 with 3 servos and 1 stepper motor

Yes, I have modified carousel to support a new feedback type "counts" where the feedback is either stepgen or encoder counts.

This new mode requires that the number of counts (or steps) between pockets is set in the carousel.N.scale pin and the width (in counts) of the pockets should be set in the "carousel.N.width"

You can try this by downloading the attached file and using the command "sudo halcompile --install carousel.comp"

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MarcusM
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17 Mar 2022 23:49 #237588 by MarcusM

Replied by MarcusM on topic Run Mesa 7i76e + 7i85 with 3 servos and 1 stepper motor

Hi Andy,

thank you so much. Compiling was successful.

I now stuck in the configuration of the linked hal file. I'll try to figure out, to which pin I have to link the correct 7i76 port.
My ATC is carousel-type (on a gantry machine). On toolchange request, the entire carousel will be moved from parking position to change position. After moving to the dedicated pocket the spindel is positioned to the change position for the toolchange itself. I think it should be possible, to use the pre-defined variables and proceedure.

The biggest knot in my brain just for the first step: How to link the hostmod stepper signal (hm2_7i76e.0.stepgen.04.?) to the toolchange_index.hal? The stepper motor obviously is started by a single signal, not by a axis command...

I attached my actual (not running) hal and ini files. Maybe you could have a short look on it.

Thanks & best regards
Marcus

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andypugh
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18 Mar 2022 00:38 #237593 by andypugh

Replied by andypugh on topic Run Mesa 7i76e + 7i85 with 3 servos and 1 stepper motor

it's rather late here, so I haven't had a very close look.

Moving the entire carousel out would normally be handled by something else. See, for example the sample configs in sim/axis/vismach/VMC_toolchange (you can just run these, they have a graphical simulated machine)

In these the carousel is moved in to place by a G-code sequence, and then carousel is enabled to move the carousel to the right tool.

In your setup you need to link carousel.counts to the stepgen counts, and the index sensor to carousel.sense-0.

I am wondering if the conv-float... items that you have copied from the sim are needed. That's all a bit inelegant. It feels like it should be possible to link the carousel.pocket to the iocontrol.0.pocket directly, then just set carousel.enable at the right point.

I _think_ this comes down to historical issues with the number actually reported by iocontrol.0.tool-prep-pocket. Is that pin showing the right numbers in your config?

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MarcusM
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18 Mar 2022 20:23 #237670 by MarcusM

Replied by MarcusM on topic Run Mesa 7i76e + 7i85 with 3 servos and 1 stepper motor

The movement of the carousel is handled by a M64 command. Works fine, the endpositions are controlled by two prox sensors. So I can do this stuff easily in the ngc files.

I still have a basic problem. I don't understand, how the carousel motor has to be connected in the hal file. As I understand, it could be controlled by a M64/M65 command. To do so, I have connect a motion.digital-out-pin to the step gen. But I have no idea, how.

What so mean with carousel.counts and the regarding link?

I'am so sorry...but i'am really confused...

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MarcusM
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18 Mar 2022 22:16 #237687 by MarcusM

Replied by MarcusM on topic Run Mesa 7i76e + 7i85 with 3 servos and 1 stepper motor

My latest (non working) config set.

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Run Mesa 7i76e + 7i85 with 3 servos and 1 stepper motor

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