How to start and use a plugin

Hardware Plugins

In this section you will learn how to create one instance of any hardware plugin (actuator, dataIO...) by a python script or the GUI of itom.

Hardware plugins are mainly divided into the following main categories:

  • DataIO contains all plugins that are related with any data input/output operation. Short, these are mainly

    • cameras and framegrabbers (organized in the subcategory Grabber),
    • AD or DA converters (subcategory ADDA) or
    • further input / output devices (subcategory Raw IO) like the serial port plugin
  • Actuator contains all motor stages, piezo actuators or further actuator devices

All valid plugins are listed in the plugin toolbox of itom


Script-based startup

In order to start a new instance of any hardware plugin using the python scripting language, search the plugin toolbox for the desired plugin and remember its plugin-name (case sensitive). Every plugin instance usually needs some mandatory and optional parameters for creating a new instance. Use the command itom.pluginHelp() in order to get information about a plugin including descriptions of its mandatory and optional parameters:


The information is then printed out in the command line of itom.

Every hardware plugin is either represented by the class itom.dataIO or itom.actuator. By creating a new instance of one of these classes, a new instance of the corresponding plugin is created. The syntax of the constructor is:

myVar = dataIO("pluginName", mandatoryParameters, optionalParameters)
myVar = actuator("pluginName", mandatoryParameters, optionalParameters)

where mandatoryParameters are all mandatory parameters (just place one value after the other one separated by commas) followed by the optional parameters. If you only want to indicate some of the optional parameters use the keyword-based argument passing of python:

serial = dataIO("SerialIO", 1, 9600, "\n", parity = 1)
# opens a serial port device at COM1 with 9600 bauds,
# an endline character '\n' and an odd parity as single optional parameters

Once an instance of a plugin is created, the corresponding entry in the plugin toolbox obtains a new child item. In Python, the variable you used for creating the plugin, is created and can now be used for controlling the plugin. As long as any variable(s) in Python still hold a reference to this plugin, its background color in the plugin toolbox is yellow.

In order to close/delete an instance of a plugin you need to delete all variables in Python that are referencing this plugin, using the command del():

del serial


Since Python has a garbage collection mechanism it is not assured that any object is immediately deleted once you delete the corresponding variable(s) in the Python workspace. It is really done if the garbage collection process is started which happens in periodical steps. You can force it using the method gc.collect() from the builtin module gc.

GUI-based startup


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