Python - find out if HAL pin exist
- zz912
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17 May 2025 15:33 #328636
by zz912
Python - find out if HAL pin exist was created by zz912
Hello,
I need read HAL pin in Python. It is not problem for me:
If the "HAL pin" exists, there is no problem:
The problem occurs when the "HAL pin" does not exist:
I would first need to find out if this "HAL pin" exists and then find out its value.
But I dont know How.
1)
Python HAL interface can check only component, not only "HAL pin".
www.linuxcnc.org/docs/html/config/python-hal-interface.html
2)
Maybe I could use Python's "Try:"
But I don't know how. I would need to check in initialization if the pin exists and store it in a variable:
halui_cmd_exist = True
or
halui_cmd_exist = False
I need read HAL pin in Python. It is not problem for me:
value = hal.get_value("halui.halui-mdi-is-running")
print(value)If the "HAL pin" exists, there is no problem:
The problem occurs when the "HAL pin" does not exist:
[Gmoccapy][ERROR] Found an error!
The following information may be useful in troubleshooting:
Traceback (most recent call last):
File "/home/zdenek/linuxcnc/linuxcnc-zz912/bin/gmoccapy", line 4220, in on_tbtn_flood_toggled
value = hal.get_value("halui.halui-mdi-is-running")
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
RuntimeError: Can't set value: pin / param halui.halui-mdi-is-running not found
(gmoccapy:62)
I would first need to find out if this "HAL pin" exists and then find out its value.
But I dont know How.
1)
Python HAL interface can check only component, not only "HAL pin".
www.linuxcnc.org/docs/html/config/python-hal-interface.html
component_exists
Does the specified component exist at this time.
Example
hal.component_exists("testpanel")2)
Maybe I could use Python's "Try:"
But I don't know how. I would need to check in initialization if the pin exists and store it in a variable:
halui_cmd_exist = True
or
halui_cmd_exist = False
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- Aciera
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17 May 2025 16:13 - 17 May 2025 16:14 #328638
by Aciera
Replied by Aciera on topic Python - find out if HAL pin exist
Try this:
try:
value = hal.get_value("halui.halui-mdi-is-running")
exists = True
except Exception:
exists = False
print(exists)
Last edit: 17 May 2025 16:14 by Aciera.
The following user(s) said Thank You: zz912
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- zz912
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17 May 2025 17:22 #328641
by zz912
Replied by zz912 on topic Python - find out if HAL pin exist
It works. Thank you.
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