Temperature Control App

Access and monitor your favorite temperature controllers from your browser.

Supported devices

Currently, supports

• Omega iSeries Ethernet: Omega iSeries controller, with Ethernet connection
• Omega iSeries Serial: Omega iSeries controller, with Serial connection

Support for more devices can be easily added. Pull requests are welcomed!

A web app that gathers data from temperature controllers and posts them to a web dashboard. Suitable for people who want to simplify day-to-day temperature routine.

Basic function like changing setpoint and ramping can be triggered inside the web app, while one can also define more complicated routines like a combination of ramping up and down involving multiple controllers.

Installation

This app requires Python 3.7+ and npm (for managing web dependencies). You should install them first and make sure they can be invoked from command line.

It is always a good habit to create a virtual environment first to make sure your local environment won't be contaminated:

python -m venv venv

Now you have two choices: install the wheel or install from source.

Install from pre-built wheel

Download pre-built wheel (.whl file) from Release and run

venv/bin/pip install [path_to_downloaded_wheel]

That's it.

Install from source

First, clone this repo to a convenient location.

After creating the virtual environment, build web assets and install them by

venv/bin/pip install .

This line will copy the source code to the site-packages location and install the package to your virtual environment. If you don't want pip to copy the source but would to like to install in place, run

venv/bin/pip install --editable .

This way, you may edit the source code under this folder and directly and run and test them easily.

Run

To run the app, simply by

venv/bin/temperature_app --config [path to config]

The format of the configuration file will be introduced in the next section.

If you stick to the default settings, you should be able to access the web app via http://{your ip address}:8000.

Configuration

The configuration file is in YAML format. Here in this repo, I present two sample configuration file config_dummy.yml (which controls two dummy test instance) and config_omega.yml. (which controls three Omega iSeries process controllers through Ethernet).

The configuration file is more or less self-explanatory. There's a few fields defines some time constants.

Network

The network section define the address and ports the server binds to. The http port is for accessing the web app. Internally, the web app communicates with the server via WebSockets, The WebSockets backend also needs a port to bind to.

Network settings can be confusing. I recommend just keep the default settings untouched, all except the line websocket_access_addr: ws://192.168.12.26:3001/ below. In order to make the web app connects to the WebSockets backend, you need to replace 192.168.12.26 with the server's own ip address.

Also, you need to set your firewall to allow incoming connection to port 8000 and 3001.

# binding to 0.0.0.0 means listening to all incoming connection, whereas
# binding to 127.0.0.1 will only accept connection from localhost
bind_addr: 0.0.0.0

# the port that serves the web server. In this case, the app can be accessed
#  via http://localost:8000
http_port: 8000

websocket_port: 3001

# == IMPORTANT: need to change 192.168.12.26 to your ip address ==
websocket_access_addr: ws://192.168.12.26:3001/

General guidelines for deploying web apps include don't expose http services on a lot of ports, use a reverse proxy instead. WebSockets endpoints can also be reverse-proxied. In general, if you are good at dealing with http server, I would suggest you do this.

Devices

The devices section defines devices the app accesses. For example,

devices:
  - name: SodiumCup(T1)
    dev_type: Omega iSeries Ethernet
    addr: 192.168.12.200
    port: 2000 

Here I defined a device called SodiumCup(T1) with device type to be Omega iSeries Ethernet. addr and port are two device-dependent parameters.

Supported devices

Currently, supports

• Omega iSeries Ethernet: Omega iSeries controller, with Ethernet connection
  • Configuration:
    • addr: IP/Hostname of the controller.
    • port: Port, should be 2000 by default.
• Omega iSeries Serial: Omega iSeries controller, with Serial connection
  • Configuration:
    • port: Serial port the controller connects to, like COM1.
    • baudrate: Should be 9600 by default.

More devices can be easily added. See the following sections.

Programs

Each program is divided into several steps, and in each step, one can specify a series of actions performed across different devices.

For actions supported, see the table below:

Operation	Description	Parameters
CHANGE	Immediately change the setpoint to a value and wait until temperature settles.	SETPOINT	Target setpoint, in °C.
LINEAR_RAMP	Linearly ramp up/down the temperature.	TARGET_TEMP	Target temperature, in °C.
		RATE	Temperature raise per minute.
SOAK	Hold the current temperature.	TIME	Duration of soak in minutes.
STANDBY	Disengage the controller. Put it into Standby mode.
LOOP	Jump back to a specific step and loop for a defined number of times.	GOTO	The number of the step to jump back to (starting from 0).
		TIMES	The number of times to loop.

The following code defines a Cool Down program that ramp down the temperatures of two different controllers (in step 0) and put both of them in standby mode (step 1).

Expressing nested list can be somewhat confusing in YAML. Please note the difference between - and - -.

  - name: Oven Cool Down
    description: Cool the sodium oven down to 20 °C in 100 minutes
    steps:
      - - action: LINEAR_RAMP
          device: SodiumCup(T1)
          params:
            TARGET_TEMP: 20
            RATE: 2
        - action: LINEAR_RAMP
          device: Flange(T2)
          params:
            TARGET_TEMP: 20
            RATE: 2.4
      - - action: STANDBY
          device: SodiumCup(T1)
        - action: STANDBY
          device: Flange(T2)

Plugins

If you have an external logger like InfluxDB, you may want to also add a plugin to grab the temperature data and upload them.

Now the only I have made is the one that pushes data to InfluxDB. To use it, add the following section to your configuration file:

influx_plugin:
  influx_api_url: http://jqi-logger.physics.umd.edu:8086/
  token: {your secret token}
  database: naer_db
  measurement: NaOven_readings
  push_interval: 0.25  # 1/4 min = 15 s

Development

This app relies on Python for the server and React.js for the web dashboard. I used quite a bit of Async IO in the server.

Add new drivers

The good news is if you just want to add new devices to this app, you don't need to know web development and Async IO. All you need is:

1. Copy driver/dummy_driver.py (which is an example) and rename it to [blah]_driver.py and put it under the driver/ folder. It has to end with _driver.py to be auto-imported by the core.
2. Rewrite all methods inside DummyDevice and functions below (see comments). This part is the code that really interacts with the controller devices.

Add plugins

You can write plugins that subscribe to the events (like status_available event) of the app core and process it in your own way. You are also free to call the event handlers insider app core just like what the web app does.

You may check out plugin/influx_push_plugin.py and change the push logic to suit your need.

Also, save you plugin into the plugin/ folder and named it with [blah]_plugin.py for the auto-import mechanism to work.