Hal Standalone. some trouble..

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13 Sep 2019 18:02 - 13 Sep 2019 18:04 #145067 by dab77
Hi, my project of a Hal standalone Gui to control a couple of motor is going on.
Working with python, I finally managed how to write it.
First I had to change from python3 to python2, because it seems to me that hal module cannot be imported in python3 (if I'm wrong please, tell me)
Than I choose Gtk, which is more natural in LinuxMint, and should be also cross-platform.

Till now I could create a hal file in-place based on the number of motors choosed (at the moment from 1 to 8, because using stepgen) and the buttons and scales in the gui also are created according to that number.

I've set all the stepgen in position mode, and it works ok, also the position feedback going back to the gui is perfectly shown.

The first big problem I cannot resolve, is deceleration in case the 'GO' button is released in the middle of a movement.
If I set stepgen.x.enable 0, the stepgen stops instantly. So I've tried to set stepgen.x.maxvel to 0, but that doesn't stop the current movement.

So here's my question:
Do you know how does it work in Axis when in jog-mode you have decelerations when stop jogging? are the stepgen temporarly set in velocity mode?

thanks, Davide.
Last edit: 13 Sep 2019 18:04 by dab77.

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13 Sep 2019 18:13 #145071 by BigJohnT
Did you set the stepgen.N.maxaccel for each axis.

JT

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13 Sep 2019 18:27 - 13 Sep 2019 18:31 #145072 by dab77
Thanks John for your fast answer.
Yes I did.
this is the GO release code:
def on_jog_go_released(self, button, name):
        ....
        for i in range(n_mot):
            try:
                os.system("halcmd setp stepgen.%d.maxvel %d" % (i, 0))
                print("vel %d changed to 0" % (i))
            except KeyboardInterrupt:
                print("Vel set error..")
...

But I just discovered that if instead of '0', i set stepgen.x.maxvel to 1 it works as expected, meaning that it decelerates as soon as I release th GO button, but unfortunately it goes at 1-speed, doesn't stop.

In the meantime I also want to ask: instead of calling "os.system("command")", is there a way to directly change a Hal Parameter in python? I've looked in the code, but didn't find anything about that..
Last edit: 13 Sep 2019 18:31 by dab77.

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13 Sep 2019 23:10 #145086 by Tower

dab77 wrote: (...)
In the meantime I also want to ask: instead of calling "os.system("command")", is there a way to directly change a Hal Parameter in python? I've looked in the code, but didn't find anything about that..


Well, there are few ways how to solve this, you can create HAL Python Userspace component which will create the HAL pins which you will be changing in your Python written program. And then you connect these pins inside the HAL layer to actual pins you need to change. That is described here: http://linuxcnc.org/docs/html/hal/halmodule.html .

Or you can create Python wrappers around the C hallib functions. That is probably quite a bit of work, but you can find the inspiration here: https://github.com/machinekit/machinekit-hal/tree/master/src/hal/cython/machinekit

Or you can create direct connector to the HAL shared memory space and change values here. This is the most hard-core option and I would not recommend this.

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14 Sep 2019 01:04 #145091 by cmorley

Well, there are few ways how to solve this, you can create HAL Python Userspace component which will create the HAL pins which you will be changing in your Python written program. And then you connect these pins inside the HAL layer to actual pins you need to change. That is described here: linuxcnc.org/docs/html/hal/halmodule.html .


You don't have to connect pins. There are some functions to do direct commands - depends on the version of linuxcnc.
in 2.7 fairly limited:
linuxcnc.org/docs/2.7/html/hal/halmodule...l#_helpful_functions
in 2.8 + a fair bit better (get_value is very useful):
linuxcnc.org/docs/2.8/html/hal/halmodule...l#_helpful_functions

Chris

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14 Sep 2019 02:14 #145096 by Tower

cmorley wrote: You don't have to connect pins. There are some functions to do direct commands - depends on the version of linuxcnc.
in 2.7 fairly limited:
(...)


Interesting, I didn't know about it. I presume there is no chance for some push notification pattern without major HAL rework, right?
(I am not Python developer, so I don't know what you are calling it in parseltongue.)

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14 Sep 2019 02:19 #145098 by cmorley
push notification?

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14 Sep 2019 10:07 #145121 by dab77

Tower wrote:

dab77 wrote: (...)
In the meantime I also want to ask: instead of calling "os.system("command")", is there a way to directly change a Hal Parameter in python? I've looked in the code, but didn't find anything about that..


Well, there are few ways how to solve this, you can create HAL Python Userspace component which will create the HAL pins which you will be changing in your Python written program. And then you connect these pins inside the HAL layer to actual pins you need to change. That is described here: http://linuxcnc.org/docs/html/hal/halmodule.html .

no, i need to change a parameter, not a pin, so i cannot link a signal to a parameter..

Or you can create Python wrappers around the C hallib functions. That is probably quite a bit of work, but you can find the inspiration here: https://github.com/machinekit/machinekit-hal/tree/master/src/hal/cython/machinekit

Or you can create direct connector to the HAL shared memory space and change values here. This is the most hard-core option and I would not recommend this.

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14 Sep 2019 10:13 #145122 by dab77

cmorley wrote:

Well, there are few ways how to solve this, you can create HAL Python Userspace component which will create the HAL pins which you will be changing in your Python written program. And then you connect these pins inside the HAL layer to actual pins you need to change. That is described here: linuxcnc.org/docs/html/hal/halmodule.html .


You don't have to connect pins. There are some functions to do direct commands - depends on the version of linuxcnc.
in 2.7 fairly limited:
linuxcnc.org/docs/2.7/html/hal/halmodule...l#_helpful_functions
in 2.8 + a fair bit better (get_value is very useful):
linuxcnc.org/docs/2.8/html/hal/halmodule...l#_helpful_functions

Chris

really, i couldn't find those functions anywhere!
thank you.
i think what i need is hal.set_p() wishing it can change parameters too.

than i still don't understand if i can toggle the stepgen command mode between velocity and position, to solve the deceleration problem.

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14 Sep 2019 13:01 - 14 Sep 2019 13:34 #145129 by dab77
the problem is this:
>>> import hal
>>> hal.set_p("stepgen.0.maxaccel", "22")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
RuntimeError: Cannot call before creating component
>>> 
I don't know how to refer to hal components.

I have also tried what is suggested in that page, while running linuxcnc, but without success:
>>> os.system("halcmd show comp")
Loaded HAL Components:
ID      Type  Name                                            PID   State
    82  User  halcmd4120                                       4120 ready
    76  User  axisui                                           4108 ready
    74  User  inihal                                           4104 ready
    65  RT    match8                                                ready
    62  RT    wcomp                                                 ready
    57  RT    comp                                                  ready
    54  RT    or2                                                   ready
    49  User  hal_manualtoolchange                             4088 ready
    43  RT    scale                                                 ready
    40  RT    near                                                  ready
    37  RT    lowpass                                               ready
    34  RT    limit2                                                ready
    31  RT    sim_spindle                                           ready
    26  RT    hypot                                                 ready
    23  RT    ddt                                                   ready
    20  RT    __servo-thread                                        ready
    19  RT    motmod                                                ready
    16  RT    trivkins                                              ready
    10  User  halui                                            4065 ready
     4  User  iocontrol                                        4063 ready

0
>>> value = hal.get_value("iocontrol.0.emc-enable-in")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
RuntimeError: Can't set value: pin / param iocontrol.0.emc-enable-in not found
>>> 
..and obviously the pin was there:
....
     4  bit   OUT         FALSE  iocontrol.0.coolant-flood
     4  bit   OUT         FALSE  iocontrol.0.coolant-mist
     4  bit   IN           TRUE  iocontrol.0.emc-enable-in <== estop-loop
     4  bit   OUT          TRUE  iocontrol.0.lube
     4  bit   IN          FALSE  iocontrol.0.lube_level
....

I've forgot to say that I have Linuxcnc 2.9.0 on..
Last edit: 14 Sep 2019 13:34 by dab77.

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