ARTIQ interacts with external devices connected to the host serial port

willow_01

I am wondering if anyone uses ARTIQ together with some external hardware devices connected to the host computer's serial ports, for example, some commercial frequency synthesizers. I googled this and the AI gave me some solutions which sound reasonable. First, in the device_db.py add this:

device_db = {
            "serial1": {
                "type": "serial",
                "port": "/dev/ttyS0", # my Linux serial port
                "baudrate": 115200,
            }
        }

and then write the ARTIQ script like this:

from artiq.experiment import *

        class MyExperiment(EnvExperiment):
            def build(self):
                self.setattr_device("core")
                self.setattr_device("serial1")

            @kernel
            def run(self):
                self.core.reset()
                self.serial1.send("Hello, world!")
                # ... more serial operations

I tried this but got the error message it showed failed to create device 'serial1'. I am wondering if anyone can suggest the right way to implement the interaction of ARTIQ with the external devices connected to the host computer through serial ports. Thanks in advance.

sb10q

AI is more A than I and you probably shouldn't be using it.

Look at existing controllers that use the serial port e.g. https://github.com/m-labs/novatech409b and the NDSP section of the manual.

willow_01

sb10q Thanks for pointing to the right direction!

willow_01

sb10q I went through the NDSP section of the ARTIQ manual and tried the hello example on my system. Everything worked okay for me until the part of integration with the ARTIQ experiment. I prepared the driver.py, aqctl_hello.py, aqcli_hello.py, as well as an empty __init__.py file in a directory of hello in my artiq-master work directory. I also prepared the device_db.py file as this

device_db = { 
    "hello": {
        "type": "controller",
        "host": "::1",
        "port": 3249,
        "command": "python hello/aqctl_hello.py -p {port}"
    }, 
}

To test this, I started the artiq_master in one terminal and started the artiq_ctlmgr in a separate terminal (both terminals with the Nix environment enabled). However, immediately after I issued the artiq_ctlmgr, I got the following message indicating that no module of sipyco:

INFO:controller(hello):print:Traceback (most recent call last):
INFO:controller(hello):print:  File "/home/fts/artiq-master/hello/aqctl_hello.py", line 4, in <module>
INFO:controller(hello):print:    from sipyco.common_args import simple_network_args
INFO:controller(hello):print:ModuleNotFoundError: No module named 'sipyco'
WARNING:ctlmgr(fts-desktop):artiq_comtools.ctlmgr:Controller hello exited
WARNING:ctlmgr(fts-desktop):artiq_comtools.ctlmgr:Restarting in 5.0 seconds

(In the aqctl_hello.py I imported the sipyco module...)

I thought that sipyco comes with the ARTIQ installation and we don't need to install it separately. Indeed, if I enter the Nix environment and start python, I can import sipyco no problem. So, my question is why sipyco is not compatible with artiq_ctlmgr and how to fix it??

I tried with ARTIQ-7 and ARTIQ-8 software on my computer and they have same issue. Thanks.

architeuthis

willow_01

When you say you start the controller manager with "Nix environment enabled", what do you mean specifically?

dly

Hi,
You could try entering the Nix environment by nix develop instead of nix shell
or
get the python path in the nix shell by which python command, it's like
/nix/store/sl2703qiyzdmvnsd0rn1mm4kljia1250-python3-3.13.5-env/bin/python in NixOS.
then in device_db.py, change
"command": "python hello/aqctl_hello.py -p {port}" into
"command": "/nix/store/sl2703qiyzdmvnsd0rn1mm4kljia1250-python3-3.13.5-env/bin/python hello/aqctl_hello.py -p {port}".
And see if master and ctlmgr can work after restart.

willow_01

dly Thanks for your suggestions. Actually, I entered the Nix Environment by $nix develop instead of $nix shell since the latter never worked for me to import the Python packages such as pandas somehow.

I tried your suggestion to give the full path of Python in my nix environment /nix/store/... in the command entry. This time I got an error message:

INFO:controller(hello):print:OSError: [Errno 98] error while attempting to bind on address ('127.0.0.1', 3249): address already in use

Thanks again for your help.

willow_01

dly I tried again your second suggestion and made it work in my case. I checked the source code of artiq_ctlmgr and found that artiq_ctlmgr used the port 3249 which I naively kept in my aqctl_hello.py as in the NDSP example. I changed the port number to another arbitrary number and used /nix/store/... python in the command entry in my device_db.py file and everything works well now.

I am still puzzled by the fact that I need to input the full path of Python in my command entry instead of just using Python. Anyway, it works now. Thanks a lot for your help!

willow_01

architeuthis I mean to start the Nix environment using $nix develop. I used $nix develop to enter the Nix environment in the two terminal windows for artiq_master and artiq_cltmgr respectively.

fsagbuya

willow_01

I am still puzzled by the fact that I need to input the full path of Python in my command entry instead of just using Python.

It's a PYTHONPATH issue and can be fixed by adding the following shellHook:

           # EDIT ABOVE
           # ========================================
         ];
+        shellHook = ''
+          export PYTHONPATH=$(python -c 'import sys; print(":".join(sys.path))')
+        '';
       };
     };
   nixConfig = {  # work around https://github.com/NixOS/nix/issues/6771

Alternatively, you can run nix develop from the ARTIQ full flake, which already handles this properly.

willow_01

fsagbuya I tried the shellHook method and it fixed the issue. Thanks!
I haven't tried the ARTIQ full flake method but it is interesting to know this.

sb10q

Why is this happening though? It doesn't make a lot of sense that ctlmgr finds sipyco but not the Python processes that it spawns. Where is the environment getting mangled and where is the best place to fix it?

fsagbuya

sb10q Possible issue and proposed fix: https://github.com/m-labs/artiq-comtools/pull/20.