OPCunix

This software is designed to comminicate with the universal cloud and aerosol sounding system (UCASS) optical particle counter (OPC) designed at the University of Hertfordshire.

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Hardware

This software has the ability to handle multiple UCASS units simultaneously, all units must be connected before the software is started. Use a USB-ISS interface to connect a unit to the computer, the interface must be connected to the SPI pins of the UCASS (this usually has a breakout connector attached for this purpose).

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Installation

Install this software using pip:

pip install UH-OPCunix-JGirdwood

Use your prefered downloader (wget used here) to download the main.py file from github into a directory of your choice:

wget https://github.com/JGirdwood/OPCunix/raw/master/main.py

Then run the main file directly, create a shortcut to where the 'main.py' file is located, or create a shell script with the following:

#!/bin/bash
python ${PATH_TO_MODULE}/main.py

Dependancies

This module requires the following modules to be installed with pip, in addition to the default python modules:

pip install pyserial pyusbiss

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Commands

The parent process in this software is a terminal program from which several different commands can be launched. Options can be specified with the commands using '-' e.g. '-n', '-p', etc. A full list of commands is displayed here:

• [OPC-unix] >> list ports - Lists all the serial ports available
• [OPC-unix] >> list ucass - Lists all the initialised UCASS units
• [OPC-unix] >> clear - Clears the screen
• [OPC-unix] >> exit - Exits the program
• [OPC-unix] >> ucass - The master for the commands associated with UCASS interfacing:
  1. init - Initialises a UCASS unit and starts recording histogram data in a subprocess (new window)
     • Options:
       1. '-n' - User specified name for the unit, used to keep track
       2. '-p' - Port to start the comminications on (i.e. /dev/tty*)
       3. '-r' - Record to file or not (boolean 1 or 0), this will also print config vars to log
  2. del - Deletes a UCASS unit and shuts down the subprocess
     • Options:
       1. '-n' - Specify the name of the unit (set during init) you want to delete
  3. conf - Read config vars and print in parent process
     • Options:
       1. '-p' - Specify the port of the unit you want to read (note this cannot be in use with init)

Examples

Example given, to initialise a UCASS unit to print histogram data to a screen:

[OPC-unix] >> list ports

This will return a list of ports e.g.:

['/dev/ttyACM0']

Next, list the config vars so the bin bounderies are known or checked:

[OPC-unix] >> ucass config -p /dev/ttyACM0

This will return the tab delimited configuration variables (and headers) printed to the terminal window. Next, start recording histogram data:

[OPC-unix] >> ucass init -n unit-E -p /dev/ttyACM0 -r 1

This will initialise a UCASS with name 'unit-E' on port '/dev/ttyACM0' and start recording to a file in a directory specified by the 'default_path.txt' file in the module. By default this is ${HOME}/UCASS_LOG/ (the directory will be created automatically if it does not exist). This command will also start a new terminal window, which will be printing out data.