Using Scripts to Access CODESYS Functionalities
All objects and command which CODESYS provides for scripting are also available in the "scriptengine
" Python module. Whenever a script is started, an implicit <code>from scriptengine import *</code>
results. This allows for easy access to CODESYS. However, if your script imports modules that require access CODESYS APIs, then these modules have to import the module scriptengine
themselves.
In the following table, you will find the main objects (categories) that can be used in Python scripts as entry points. For comprehensive documentation about entry points, see the API reference documentation for the CODESYS ScriptEngine.
Objects | Description |
---|---|
System | Access to general CODESYS functionalities Examples:
|
projects | Access to the CODESYS project as an object tree that combines the three navigator views (devices, POUs, modules) in one project tree Also allows for the loading, creating, saving, and closing of projects For most objects in a project, there are special methods with detailed functionality, for example compiling, access to ST POUs, export, import, device configuration, etc. |
online | Access to online functionalities Examples:
|
librarymanager | Permits the management of library repositories and viewing, installation, and removal of libraries |
device_repository | Handling of device repositories; import and export of device descriptions |
modulerepository | Management of CODESYS Application Composer modules and CODESYS Application Composer repositories |
See the following specific sample scripts for ways to access CODESYS functionalities. For detailed information, see the API reference documentation for the CODESYS.
Example: Printing the device tree of the current project
The script PrintDeviceTree.py
is an example for navigating in a project. It creates the output of a hierarchical display of all devices in the open project.
Load a project that contains some device objects and execute the script.
PrintDeviceTree.py
# encoding:utf-8 # We enable the new python 3 print syntax from __future__ import print_function # Prints out all devices in the currently open project. print("--- Printing the devices of the project: ---") # Define the printing function. This function starts with the # so called "docstring" which is the recommended way to document # functions in python. def print_tree(treeobj, depth=0): """ Print a device and all its children Arguments: treeobj -- the object to print depth -- The current depth within the tree (default 0). The argument 'depth' is used by recursive call and should not be supplied by the user. """ # if the current object is a device, we print the name and device identification. if treeobj.is_device: name = treeobj.get_name(False) deviceid = treeobj.get_device_identification() print("{0}- {1} {2}".format("--"*depth, name, deviceid)) # we recursively call the print_tree function for the child objects. for child in treeobj.get_children(False): print_tree(child, depth+1) # We iterate over all top level objects and call the print_tree function for them. for obj in projects.primary.get_children(): print_tree(obj) print("--- Script finished. ---")
The device tree (from the "Devices" view) is displayed in the message view and all non-device objects are left out:

Example: Reading of variables
The script ReadVariable.py
logs in to the device and starts the application if necessary. Then the value of the variable PLC_PRG.iVar1
is read and output. To try the script, you have to modify the project path and variable names.
ReadVariable.py
# encoding:utf-8 from __future__ import print_function # close open project if necessary: if projects.primary: projects.primary.close() # opens project proj = projects.open(r"D:\data\projects\Ampel.project") # set "Ampel.project" to active application app = proj.active_application onlineapp = online.create_online_application(app) # login to device onlineapp.login(OnlineChangeOption.Try, True) # set status of application to "run", if not in "run" if not onlineapp.application_state == ApplicationState.run: onlineapp.start() # wait 1 second system.delay(1000) # read value of iVar1 value = onlineapp.read_value("PLC_PRG.iVar1") # display value in message view or command line print(value) # log out from device and close "Ampel.project" onlineapp.logout() proj.close()
In the extension of the script ReadVariable.py
, the script MailVariables.py
loads variables and expressions from a recipe file and reads their current values from the controller. Then these values are written back to the same file. In addition, is uses the Python SMTP library to send an email with an attachment containing a list of all variables.
To use the script, you have to modify the paths, email address, and the name of the SMTP server to your environment.
MailVariables.py
# encoding:utf-8 from __future__ import print_function # Close current project if necessary and open "ScriptTest.project" if not projects.primary == None: projects.primary.close() project = projects.open("D:\\Data\\projects\\scriptTest.project") # retrieve active application application = project.active_application # create online application online_application = online.create_online_application(application) # login to application. online_application.login(OnlineChangeOption.Try, True) # start PLC if necessary if not online_application.application_state == ApplicationState.run: online_application.start() # wait 2 seconds system.delay(2000) # open recipe file to read values. recipe_input_file = open("D:\\Data\\projects\\RecipeInput.txt", "r") watch_expressions = [] for watch_expression in recipe_input_file: watch_expressions.append(watch_expression.strip()) print watch_expressions # read values from the controllerd watch_values = online_application.read_values(watch_expressions) print watch_values # open output file to write values recipe_output_file = open("D:\\Data\\projects\\RecipeOutput.txt", "w") for i in range(len(watch_expressions)): recipe_output_file.write(watch_expressions[i]) recipe_output_file.write(" = ") recipe_output_file.write(watch_values[i]) recipe_output_file.write("\n") # Close files recipe_input_file.close() recipe_output_file.close() # send Email # import respective libraries import smtplib from email.mime.text import MIMEText #open output file recipe_output_file = open("D:\\Data\\projects\\RecipeOutput.txt", "r") mail = MIMEText(recipe_output_file.read()) recipe_output_file.close() #email address sender and recipient fromm = "info@example.com" to = "info@example.com" # set sender and recipient mail["Subject"] = "Attention value has changed" mail["From"] = fromm mail["To"] = to # send email smtp = smtplib.SMTP("name of smtp server") smtp.sendmail(fromm, [to], mail.as_string()) smtp.quit() # logout and close application online_application.logout() project.close()
Example: Creating and editing of POUs
The script CreateDut.py
creates the objects MyStruct
, MyAlias
, and MyUnion
in the CODESYS project. The folder DataTypes
already has to be present.
# encoding:utf-8 from __future__ import print_function STRUCT_CONTENT = """\ a : BOOL; b : BIT; c : BIT; """ UNION_WHOLE = """\ TYPE MyUnion : UNION Zahl : INT; Prozent : MyAlias; Bits : MyStruct; END_UNION END_TYPE """ proj = projects.primary folder = proj.find('DataTypes', recursive = True)[0] # Create a struct DUT and insert the list of variables just into the right # place in line two, row 0 (line numbering starts with line 0) struktur = folder.create_dut('MyStruct') # DutType.Structure is the default struktur.textual_declaration.insert(2, 0, STRUCT_CONTENT) # Alias types get their "content" via the base type, which will just end up # as one line in the declaration part: # TYPE MyAlias : INT (0..100); END_TYPE bereich = folder.create_dut('MyAlias', DutType.Alias, "INT (0..100)") # Instead of injecting the variables into the existing declaration, # one can also just replace the complete declaration part, including the # boilerplate code. union = folder.create_dut('MyUnion', DutType.Union) union.textual_declaration.replace(UNION_WHOLE)
Example: User interface / Interaction with the user
In some cases, scripts have to interact with the user. We provide some simple APIs for the most common interactions. The sample script System_UI_Test.py
shows all of the possible functions in this regard.
System_UI_Test.py
# encoding:utf-8 from __future__ import print_function """Performs some tests on the messagestore and UI.""" print("Some Error, Warning and Information popups:") system.ui.error("Fatal error: Everything is OK. :-)") system.ui.warning("Your bank account is surprisingly low") system.ui.info("Just for your information: 42") print("Now, we ask the user something.") res = system.ui.prompt("Do you like this?", PromptChoice.YesNo, PromptResult.Yes); print("The user selected '%s'" % res) print("Now, the user can choose between custom options:") res = system.ui.choose("Please choose:", ("First", 2, 7.5, "Something else")) print("The user selected option '%s'" % str(res)) # res is a tuple print("Now, the user can choose several options:") res = system.ui.select_many("Please select one or more options", PromptChoice.OKCancel, PromptResult.OK, ("La Premiere", "The Second", "Das Dritte")) print("The returned result is: '%s'" % str(res)) # res is a tuple print("Now, the user can select files and directories") res = system.ui.open_file_dialog("Choose multiple files:", filter="Text files (*.txt)|*.txt|Image Files(*.BMP;*.JPG;*.GIF)|*.BMP;*.JPG;*.GIF|All files (*.*)|*.*", filter_index = 0, multiselect=True) print("The user did choose: '%s'" % str(res)) # res is a tuple as multiselect is true. res = system.ui.save_file_dialog("Choose a file to save:", filter="Text files (*.txt)|*.txt|Image Files(*.BMP;*.JPG;*.GIF)|*.BMP;*.JPG;*.GIF|All files (*.*)|*.*", filter_index = 0) print("The user did choose: '%s'" % res) res = system.ui.browse_directory_dialog("Choose a directory", path="C:\\") print("The user did choose: '%s'" % res) print("Now we query a single line string") res = system.ui.query_string("What's your name?") print("Nice to meet you, dear %s." % res) print("Now we query a multi line string") res = system.ui.query_string("Please tell me a nice story about your life!", multi_line=True) if (res): print("Huh, that has been a long text, at least %s characters!" % len(res)) else: print("Hey, don't be lazy!") print("Username and passwort prompts...") res = system.ui.query_password("Please enter your favourite password!", cancellable=True) if res: print("Huh, it's very careless to tell me your favourite password '%s'!" % res) else: print("Ok, if you don't want...") res = system.ui.query_credentials("Now, for real...") if res: print("Username '%s' and password '%s'" % res) # res is a 2-tuple else: print("Sigh...")
Example: Manipulating the Project Information object
In the script ProjectInfoExample.py
, we set some information in the Project Information object. The most important information items, such as Title and Version, have explicit properties. However, you can read and write any other information fields by means of the dictionary
syntax. For example, those that are recommended for the properties of a library project.
The example below may seem somewhat unrealistic, but similar code is used in build servers that create, test, and possibly release automatic library projects and other projects. The ScriptEngine is one of the key elements for creating CI (Continuous Integration) and CD (Continuous Delivery) systems.
ProjectInfoExample.py
# encoding:utf-8 from __future__ import print_function proj = projects.load("D:\Some.library") info = proj.get_project_info() # Set some values info.company = "Test Library Ltd" info.title = "Script Test Project" info.version = (0, 8, 15, 4711) info.default_namespace = "testlibrary" info.author = "Python von Scriptinger" # some values recommended in the library toolchain info.values["DefaultNamespace"] = "testlibrary" info.values["Placeholder"] = "testlibrary" info.values["DocFormat"] = "reStructuredText" # now we set a custom / vendor specific value. info.values["SpecialDeviceId"] = "PLC0815_4711" # Enable generation of Accessor functions, so the IEC # application can display the version in an info screen. info.change_accessor_generation(True) # And set the library to released info.released = True; proj.save()
Example: Calling external commands and importing PLCOpenXML files
The sample script DeviceImportFromSVN.py
gets a PLCOpenXML file from an external program (in this case a SVN client) and imports it into a new created CODESYS project.
To use the script, you have to modify the paths to your environment.
DeviceImportFromSVN.py
# encoding:utf-8 # Imports a Device in PLCOpenXML from Subversion via command line svn client. # We enable the new python 3 print syntax from __future__ import print_function import sys, os # some variable definitions: SVNEXE = r"C:\Program Files\Subversion\bin\svn.exe" XMLURL = "file:///D:/testrepo/testfolder/TestExport.xml" PROJECT = r"D:\test.project" # clean up any open project: if projects.primary: projects.primary.close() # Fetch the plcopenxml data from subversion. # We'll catch the output of the program into the xmldata variable. # The 'with' construct automatically closes the open pipe for us. with os.popen('"' + SVNEXE + '" cat ' + XMLURL, 'r') as pipe: xmldata = pipe.read() # create a new project: proj = projects.create(PROJECT) # import the data into the project. proj.import_xml(xmldata, False) # and finally save. :-) proj.save() print("--- Script finished. ---")
Advanced example: Calling a library from SVN and installing it in CODESYS
The following sample script can perform the calling and installing of a library as part of a CT (Continuous Testing) environment so that they can be tested. In addition to standard-CODESYS, the CODESYS SVN add-on also has to be installed with a valid license.
import tempfile if projects.primary: projects.primary.close() tempdir = tempfile.mkdtemp() URL = "svn://localhost/testrepo/trunk/SvnTestLibrary/" proj = svn.checkout(URL, tempdir, "testlibrary", as_library=True) proj.save() repo = librarymanager.repositories[0] librarymanager.install_library(proj.path, repo, True) proj.close()