Error when deployin a dash app to heroku, Nidaqmx.lib.DaqNotFoundError

Question

I am trying to remotely read data from an accelerometer using a NI9234. I am working in windows, and I am usnig plotly dash and nidaqmx on python. The whole thing works fine on the local host (is able to fetch the data and it's plotting it), however, when I try to deploy it on Heroku, my accelerometer is not reading anything at all. I think that the deployment is working, but I have this as my log --tail:

2021-06-19T01:12:23.045293+00:00 heroku[router]: at=info method=GET path="/_dash-component-suites/dash_core_components/async-plotlyjs.v1_16_0m1617903285.js" host=monitoreo-remoto.herokuapp.com request_id=cc5a2471-0689-4b93-91cb-a0d0eb796e82 fwd="187.190.230.255" dyno=web.1 connect=0ms service=325ms status=200 bytes=1034463 protocol=https
2021-06-19T01:12:28.412217+00:00 app[web.1]: Exception on /_dash-update-component [POST]
2021-06-19T01:12:28.412225+00:00 app[web.1]: Traceback (most recent call last):
2021-06-19T01:12:28.412226+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 2070, in wsgi_app
2021-06-19T01:12:28.412227+00:00 app[web.1]: response = self.full_dispatch_request()
2021-06-19T01:12:28.412227+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 1515, in full_dispatch_request
2021-06-19T01:12:28.412228+00:00 app[web.1]: rv = self.handle_user_exception(e)
2021-06-19T01:12:28.412228+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 1513, in full_dispatch_request
2021-06-19T01:12:28.412228+00:00 app[web.1]: rv = self.dispatch_request()
2021-06-19T01:12:28.412229+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 1499, in dispatch_request
2021-06-19T01:12:28.412229+00:00 app[web.1]: return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
2021-06-19T01:12:28.412230+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/dash/dash.py", line 1079, in dispatch
2021-06-19T01:12:28.412230+00:00 app[web.1]: response.set_data(func(*args, outputs_list=outputs_list))
2021-06-19T01:12:28.412231+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/dash/dash.py", line 1010, in add_context
2021-06-19T01:12:28.412232+00:00 app[web.1]: output_value = func(*args, **kwargs)  # %% callback invoked %%
2021-06-19T01:12:28.412232+00:00 app[web.1]: File "/app/Vib-easy-3.py", line 110, in update_output
2021-06-19T01:12:28.412233+00:00 app[web.1]: with nidaqmx.Task() as task:
2021-06-19T01:12:28.412233+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/task.py", line 84, in __init__
2021-06-19T01:12:28.412233+00:00 app[web.1]: self._handle = lib_importer.task_handle(0)
2021-06-19T01:12:28.412234+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 178, in task_handle
2021-06-19T01:12:28.412234+00:00 app[web.1]: self._parse_typedefs()
2021-06-19T01:12:28.412235+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 241, in _parse_typedefs
2021-06-19T01:12:28.412235+00:00 app[web.1]: version = system.driver_version
2021-06-19T01:12:28.412236+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/system/system.py", line 73, in driver_version
2021-06-19T01:12:28.412236+00:00 app[web.1]: return DriverVersion(self._major_version, self._minor_version,
2021-06-19T01:12:28.412236+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/system/system.py", line 108, in _major_version
2021-06-19T01:12:28.412237+00:00 app[web.1]: cfunc = lib_importer.windll.DAQmxGetSysNIDAQMajorVersion
2021-06-19T01:12:28.412237+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 166, in windll
2021-06-19T01:12:28.412238+00:00 app[web.1]: self._import_lib()
2021-06-19T01:12:28.412244+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 218, in _import_lib
2021-06-19T01:12:28.412244+00:00 app[web.1]: raise DaqNotFoundError(
2021-06-19T01:12:28.412252+00:00 app[web.1]: nidaqmx._lib.DaqNotFoundError: Could not find an installation of NI-DAQmx. Please ensure that NI-DAQmx is installed on this machine or contact National Instruments for support.
2021-06-19T01:12:28.418592+00:00 app[web.1]: 10.16.188.22 - - [19/Jun/2021:01:12:28 +0000] "POST /_dash-update-component HTTP/1.1" 500 290 "https://monitoreo-remoto.herokuapp.com/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.106 Safari/537.36"
2021-06-19T01:12:28.418956+00:00 heroku[router]: at=info method=POST path="/_dash-update-component" host=monitoreo-remoto.herokuapp.com request_id=fde7d56c-acbe-45f9-a1a6-54293cb22e55 fwd="187.190.230.255" dyno=web.1 connect=0ms service=181ms status=500 bytes=463 protocol=https
2021-06-19T01:12:44.515889+00:00 app[web.1]: Exception on /_dash-update-component [POST]
2021-06-19T01:12:44.515899+00:00 app[web.1]: Traceback (most recent call last):
2021-06-19T01:12:44.515900+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 2070, in wsgi_app
2021-06-19T01:12:44.515901+00:00 app[web.1]: response = self.full_dispatch_request()
2021-06-19T01:12:44.515901+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 1515, in full_dispatch_request
2021-06-19T01:12:44.515902+00:00 app[web.1]: rv = self.handle_user_exception(e)
2021-06-19T01:12:44.515902+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 1513, in full_dispatch_request
2021-06-19T01:12:44.515903+00:00 app[web.1]: rv = self.dispatch_request()
2021-06-19T01:12:44.515903+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 1499, in dispatch_request
2021-06-19T01:12:44.515904+00:00 app[web.1]: return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
2021-06-19T01:12:44.515904+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/dash/dash.py", line 1079, in dispatch
2021-06-19T01:12:44.515905+00:00 app[web.1]: response.set_data(func(*args, outputs_list=outputs_list))
2021-06-19T01:12:44.515905+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/dash/dash.py", line 1010, in add_context
2021-06-19T01:12:44.515906+00:00 app[web.1]: output_value = func(*args, **kwargs)  # %% callback invoked %%
2021-06-19T01:12:44.515906+00:00 app[web.1]: File "/app/Vib-easy-3.py", line 110, in update_output
2021-06-19T01:12:44.515906+00:00 app[web.1]: with nidaqmx.Task() as task:
2021-06-19T01:12:44.515907+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/task.py", line 84, in __init__
2021-06-19T01:12:44.515907+00:00 app[web.1]: self._handle = lib_importer.task_handle(0)
2021-06-19T01:12:44.515916+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 178, in task_handle
2021-06-19T01:12:44.515917+00:00 app[web.1]: self._parse_typedefs()
2021-06-19T01:12:44.515917+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 241, in _parse_typedefs
2021-06-19T01:12:44.515918+00:00 app[web.1]: version = system.driver_version
2021-06-19T01:12:44.515918+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/system/system.py", line 73, in driver_version
2021-06-19T01:12:44.515919+00:00 app[web.1]: return DriverVersion(self._major_version, self._minor_version,
2021-06-19T01:12:44.515919+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/system/system.py", line 108, in _major_version
2021-06-19T01:12:44.515919+00:00 app[web.1]: cfunc = lib_importer.windll.DAQmxGetSysNIDAQMajorVersion
2021-06-19T01:12:44.515920+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 166, in windll
2021-06-19T01:12:44.515920+00:00 app[web.1]: self._import_lib()
2021-06-19T01:12:44.515920+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 218, in _import_lib
2021-06-19T01:12:44.515920+00:00 app[web.1]: raise DaqNotFoundError(
2021-06-19T01:12:44.515921+00:00 app[web.1]: nidaqmx._lib.DaqNotFoundError: Could not find an installation of NI-DAQmx. Please ensure that NI-DAQmx is installed on this machine or contact National Instruments for support.
2021-06-19T01:12:44.530403+00:00 app[web.1]: 10.16.188.22 - - [19/Jun/2021:01:12:44 +0000] "POST /_dash-update-component HTTP/1.1" 500 290 "https://monitoreo-remoto.herokuapp.com/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.106 Safari/537.36"
2021-06-19T01:12:44.531107+00:00 heroku[router]: at=info method=POST path="/_dash-update-component" host=monitoreo-remoto.herokuapp.com request_id=4cd69bda-50c6-4bd5-8a33-3cd423c725d1 fwd="187.190.230.255" dyno=web.1 connect=1ms service=179ms status=500 bytes=463 protocol=https
2021-06-19T01:12:48.609521+00:00 app[web.1]: Exception on /_dash-update-component [POST]
2021-06-19T01:12:48.609530+00:00 app[web.1]: Traceback (most recent call last):
2021-06-19T01:12:48.609531+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 2070, in wsgi_app
2021-06-19T01:12:48.609531+00:00 app[web.1]: response = self.full_dispatch_request()
2021-06-19T01:12:48.609532+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 1515, in full_dispatch_request
2021-06-19T01:12:48.609532+00:00 app[web.1]: rv = self.handle_user_exception(e)
2021-06-19T01:12:48.609533+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 1513, in full_dispatch_request
2021-06-19T01:12:48.609533+00:00 app[web.1]: rv = self.dispatch_request()
2021-06-19T01:12:48.609534+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 1499, in dispatch_request
2021-06-19T01:12:48.609534+00:00 app[web.1]: return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
2021-06-19T01:12:48.609534+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/dash/dash.py", line 1079, in dispatch
2021-06-19T01:12:48.609535+00:00 app[web.1]: response.set_data(func(*args, outputs_list=outputs_list))
2021-06-19T01:12:48.609535+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/dash/dash.py", line 1010, in add_context
2021-06-19T01:12:48.609536+00:00 app[web.1]: output_value = func(*args, **kwargs)  # %% callback invoked %%
2021-06-19T01:12:48.609536+00:00 app[web.1]: File "/app/Vib-easy-3.py", line 110, in update_output
2021-06-19T01:12:48.609537+00:00 app[web.1]: with nidaqmx.Task() as task:
2021-06-19T01:12:48.609537+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/task.py", line 84, in __init__
2021-06-19T01:12:48.609537+00:00 app[web.1]: self._handle = lib_importer.task_handle(0)
2021-06-19T01:12:48.609538+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 178, in task_handle
2021-06-19T01:12:48.609538+00:00 app[web.1]: self._parse_typedefs()
2021-06-19T01:12:48.609539+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 241, in _parse_typedefs
2021-06-19T01:12:48.609539+00:00 app[web.1]: version = system.driver_version
2021-06-19T01:12:48.609540+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/system/system.py", line 73, in driver_version
2021-06-19T01:12:48.609540+00:00 app[web.1]: return DriverVersion(self._major_version, self._minor_version,
2021-06-19T01:12:48.609540+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/system/system.py", line 108, in _major_version
2021-06-19T01:12:48.609541+00:00 app[web.1]: cfunc = lib_importer.windll.DAQmxGetSysNIDAQMajorVersion
2021-06-19T01:12:48.609541+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 166, in windll
2021-06-19T01:12:48.609542+00:00 app[web.1]: self._import_lib()
2021-06-19T01:12:48.609542+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 218, in _import_lib
2021-06-19T01:12:48.609542+00:00 app[web.1]: raise DaqNotFoundError(
2021-06-19T01:12:48.609543+00:00 app[web.1]: nidaqmx._lib.DaqNotFoundError: Could not find an installation of NI-DAQmx. Please ensure that NI-DAQmx is installed on this machine or contact National Instruments for support.
2021-06-19T01:12:48.612660+00:00 app[web.1]: 10.16.188.22 - - [19/Jun/2021:01:12:48 +0000] "POST /_dash-update-component HTTP/1.1" 500 290 "https://monitoreo-remoto.herokuapp.com/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.106 Safari/537.36"
2021-06-19T01:12:48.613854+00:00 heroku[router]: at=info method=POST path="/_dash-update-component" host=monitoreo-remoto.herokuapp.com request_id=5a31bc51-2eef-4370-91bf-e91b144e2b37 fwd="187.190.230.255" dyno=web.1 connect=0ms service=185ms status=500 bytes=463 protocol=https
2021-06-19T01:15:31.312757+00:00 app[web.1]: Exception on /_dash-update-component [POST]
2021-06-19T01:15:31.312766+00:00 app[web.1]: Traceback (most recent call last):
2021-06-19T01:15:31.312770+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 2070, in wsgi_app
2021-06-19T01:15:31.312770+00:00 app[web.1]: response = self.full_dispatch_request()
2021-06-19T01:15:31.312771+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 1515, in full_dispatch_request
2021-06-19T01:15:31.312771+00:00 app[web.1]: rv = self.handle_user_exception(e)
2021-06-19T01:15:31.312771+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 1513, in full_dispatch_request
2021-06-19T01:15:31.312772+00:00 app[web.1]: rv = self.dispatch_request()
2021-06-19T01:15:31.312772+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/flask/app.py", line 1499, in dispatch_request
2021-06-19T01:15:31.312773+00:00 app[web.1]: return self.ensure_sync(self.view_functions[rule.endpoint])(**req.view_args)
2021-06-19T01:15:31.312773+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/dash/dash.py", line 1079, in dispatch
2021-06-19T01:15:31.312774+00:00 app[web.1]: response.set_data(func(*args, outputs_list=outputs_list))
2021-06-19T01:15:31.312774+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/dash/dash.py", line 1010, in add_context
2021-06-19T01:15:31.312775+00:00 app[web.1]: output_value = func(*args, **kwargs)  # %% callback invoked %%
2021-06-19T01:15:31.312775+00:00 app[web.1]: File "/app/Vib-easy-3.py", line 110, in update_output
2021-06-19T01:15:31.312776+00:00 app[web.1]: with nidaqmx.Task() as task:
2021-06-19T01:15:31.312776+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/task.py", line 84, in __init__
2021-06-19T01:15:31.312777+00:00 app[web.1]: self._handle = lib_importer.task_handle(0)
2021-06-19T01:15:31.312777+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 178, in task_handle
2021-06-19T01:15:31.312778+00:00 app[web.1]: self._parse_typedefs()
2021-06-19T01:15:31.312778+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 241, in _parse_typedefs
2021-06-19T01:15:31.312779+00:00 app[web.1]: version = system.driver_version
2021-06-19T01:15:31.312779+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/system/system.py", line 73, in driver_version
2021-06-19T01:15:31.312780+00:00 app[web.1]: return DriverVersion(self._major_version, self._minor_version,
2021-06-19T01:15:31.312780+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/system/system.py", line 108, in _major_version
2021-06-19T01:15:31.312780+00:00 app[web.1]: cfunc = lib_importer.windll.DAQmxGetSysNIDAQMajorVersion
2021-06-19T01:15:31.312781+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 166, in windll
2021-06-19T01:15:31.312781+00:00 app[web.1]: self._import_lib()
2021-06-19T01:15:31.312781+00:00 app[web.1]: File "/app/.heroku/python/lib/python3.9/site-packages/nidaqmx/_lib.py", line 218, in _import_lib
2021-06-19T01:15:31.312782+00:00 app[web.1]: raise DaqNotFoundError(
2021-06-19T01:15:31.312783+00:00 app[web.1]: nidaqmx._lib.DaqNotFoundError: Could not find an installation of NI-DAQmx. Please ensure that NI-DAQmx is installed on this machine or contact National Instruments for support.
2021-06-19T01:15:31.317641+00:00 app[web.1]: 10.5.190.247 - - [19/Jun/2021:01:15:31 +0000] "POST /_dash-update-component HTTP/1.1" 500 290 "https://monitoreo-remoto.herokuapp.com/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.106 Safari/537.36"
2021-06-19T01:15:31.315041+00:00 heroku[router]: at=info method=POST path="/_dash-update-component" host=monitoreo-remoto.herokuapp.com request_id=b613139d-c395-4571-923c-1f6c466a1b2d fwd="187.190.230.255" dyno=web.1 connect=1ms service=131ms status=500 bytes=463 protocol=https

I don't know which part is important, but the following line caught my eye:

nidaqmx._lib.DaqNotFoundError: Could not find an installation of NI-DAQmx. Please ensure that NI-DAQmx is installed on this machine or contact National Instruments for support.

I am using the free Heroku version, but I don't know if anyone in here have ran into this problem.

Answer 1

After many days without an answer I will be posting what I think it was happening, and also post a viable solution that doesn't involve heroku.

My theory: nidaqmx library in python needs the download from National Instruments. if you do not have it, then it won't work. The installation is only available for windows. I guess the servers of Heroku don't have these files.

After Heroku, I tried to run my program in pythonanywhere, and even used Docker; none of these methods were working (perhaps I did something wrong, or perhaps it was kind of the same problem from above)

After many days of reading stuff, searching the web, and trying with different methods, I found a nice and easy solution; ngrok.

Basically you just need to register, download the zip, unzip it and paste the ngrok.exe in C:/Windows/system32. Add the path to your env variables (check answer from il0v3d0g), and later run your dash app in local server (port 3040 , for example) and finally run the ngrok command in another windows bash cmd

ngrok http 3040

This will create a "tunnel" between your local host (that is running your dash app) and any other computer from anywhere in the internet with the forwarding address that ngrok is creating.

This is a crude schematic of my "settings"

And in case anybody is wondering what the dash app looks like, I am adding it as well (in the case any engineer like myself is caught in the horrible task of working with remote data fetching)

#Working program, on dash program folder.
#Working with bootstrap instead of daq.
# Se debe instalar bootstrap: pip install bootstrap-core-components
import dash
import dash_bootstrap_components as dbc
import dash_core_components as dcc
import dash_html_components as html
from dash.dependencies import Input, Output
import plotly.graph_objects as go
from dash.exceptions import PreventUpdate
import nidaqmx
from nidaqmx.constants import AcquisitionType
import numpy as np

app = dash.Dash(__name__)

#Initial conditions to have something in the graph
trace_1 = go.Scatter(
    x = [],
    y = []
)

layout = go.Layout(title = 'Título de gráfica')
fig = go.Figure(data = [trace_1], layout = layout)

app.layout = dbc.Container(
    [
# Toma todo el espacio de arriba para el título.
        dbc.Row(
            dbc.Col(html.H3('Monitoreo Remoto V-0.3', className = 'text-center text-primary mb-4'), width = 12)
        ),
# Esto es otra fila que va a tener dos dropdowns y el botón en la misma columna
        dbc.Row(
            [
                dbc.Col(
                    [   
                        dbc.Button(
                        'Capturar',
                        color = 'primary',
                        id = 'Swtc_1',
                        n_clicks = 0
                        ),
                        dcc.Dropdown(
                        id = 'f_muestreo',
                        value = '2048',
                        multi = False,
                        disabled = False,
                        persistence = 'string',
                        persistence_type = 'session',
                        options = [
                            {'label' : '2048', 'value':'2048'},
                            {'label' : '2560', 'value':'2560'},
                            {'label' : '3200', 'value':'3200'},
                            {'label' : '5120', 'value':'5120'},
                            {'label' : '6400', 'value':'6400'},
                            {'label' : '10240', 'value':'10240'},
                            {'label' : '12800', 'value':'12800'},
                            {'label' : '25600', 'value':'25600'}
                        ],
                        ),
                        dcc.Dropdown(
                        id = 'muestras',
                        value = '2048',
                        multi = False,
                        disabled = False,
                        persistence = 'string',
                        persistence_type = 'session',
                        options = [
                            {'label' : '2048', 'value':'2048'},
                            {'label' : '4096', 'value':'4096'},
                            {'label' : '8192', 'value':'8192'},
                            {'label' : '16384', 'value':'16384'},
                            {'label' : '32768', 'value':'32768'},
                            {'label' : '65536', 'value':'65536'},
                            {'label' : '131072', 'value':'131072'}
                        ],
                        ),
                    ], width = 2
                ),
# Dentro de la misma fila, se va a meter una nueva columna; para la gráfica. 
                dbc.Col(
                    dcc.Graph(id = 'plot_id', figure = fig), width = 9
                )
            ],
        )
    ]
)    
# interaction
@app.callback(
    Output('plot_id', 'figure'),
    [Input('Swtc_1', 'n_clicks'),
    Input('f_muestreo', 'value'),
    Input('muestras', 'value')]   
)

def update_output(n_clicks, value_1, value_2):
    changed_id = [p['prop_id'] for p in dash.callback_context.triggered][0]
    if 'n_clicks' in changed_id:
        sample_rate = int(value_1)
        samples_to_acq = int(value_2)
        wait_time = samples_to_acq/sample_rate
# Name and channel of my NI 9234
        channel_name = 'cDAQBAYO1Mod1/ai0'
# Not using the trig yet
#        trig_name = 'cDAQBAYO1Mod1/ai1'
        cont_mode = AcquisitionType.CONTINUOUS
        units_g = nidaqmx.constants.AccelUnits.G
        with nidaqmx.Task() as task:
# Create accelerometer channel and configure sample clock and trigger specs
            task.ai_channels.add_ai_accel_chan(channel_name, units = units_g)
            task.timing.cfg_samp_clk_timing(sample_rate, sample_mode = cont_mode, samps_per_chan=samples_to_acq)
# Esto es para el tacómetro, de momento está omitido
#            task.triggers.start_trigger.cfg_dig_edge_start_trig(trigger_source = trig_name)
    
#   Reading data from sensor and generating time data with numpy
            ydata = task.read(number_of_samples_per_channel=samples_to_acq)
            xdata = np.linspace(0, wait_time,samples_to_acq)
        
            trace_1 = go.Scatter(
                x = list(xdata),
                y = list(ydata)
            )
            layout = go.Layout(title = 'Oscilograma')
            fig = go.Figure(data = [trace_1], layout = layout)
            n_clicks = 0
        return (fig)
    else:
        raise PreventUpdate    
   

if __name__ == '__main__':
    app.run_server(debug = False, port = 3040)