========================= RSLogix .L5X Interface

This package aims to implement an interface for manipulating content of RSLogix .L5X export files using a native Pythonic approach as opposed to dealing with raw XML.

Getting Started

All access to .L5X data is through a top-level Project object, instantiated by passing a filename to the constructor. If the project is to be modified the write method writes the updated data back to a file for importing into RSLogix. Typical execution flow is as follows:

::

import l5x
prj = l5x.Project('project.L5X')

# Read or modify data as needed.

prj.write('modified.L5X')

Controller

The controller attribute of a project has the following attributes:

tags: A tag scope containing controller tags; see Tags_.

comm_path: Permits reading and modifying the controller's communication path. Setting to None will delete the communication path.

::

>>> prj.controller.tags['tag_name'].description = 'A controller tag'
>>> prj.controller.comm_path
'AB_ETHIP-1\\192.168.1.10\\Backplane\\0'

snn: Safety network number; see Modules_ for details.

Programs

A project's programs attribute contains a names attribute that evaluates to an iterable of program names, members of which can be used as indices to access program-scoped tags.

::

>>> prj.programs.names
['MainProgram', 'AnotherProgram']
>>> prj.programs['MainProgram'].tags['a_program_tag'].value = 50

Tags

The top-level project contains tag scope objects, such as controller or programs, which provide access to their respective tags. Indexing a scope object with a tag's name will return a tag object providing access to the various properties of the tag. An iterable of tag names can also be acquired from a scope's names attribute.

::

ctl_tags = prj.controller.tags
tag_names = ctl_tags.names
some_tag = ctl_tags[tag_names[0]]

All tag objects have at least the following attributes:

data_type A string describing the tag's data type, such as DINT or TIMER.

value The tag's complete value, the type of which varies based on the tag's type. For base data types this will be a single value, such as an integer, however, container objects are utilized for compound data types such as arrays and UDTs. See documentation below for details. This attribute can be read to acquire the current value or written to set a new value.

description The tag's top-level comment. See data type specific documentation for data types which support commenting subelements such as individual array members or integer bits. In addition to normal read/write activities, setting this attribute to None will delete any existing comment.

    Recent versions of RSLogix have implemented maintaining comments and
    descriptions in multiple languages. Adding, removing, or modifying
    comments with the L5X package will only affect comments in the
    project's current language. Changing the current language, or
    manipulating comments in other languages is currently not implemented.

Consumed tags include these additional read/write attributes:

producer Name of the producing controller.

remote_tag Remote tag name.

Integers

DINT, INT, and SINT data types accept integer values.

::

	prj.controller.tags['dint_tag'].value = 42

Accessing individual bits is available via index notation with a zero-based
integer index:

::

	prj.controller.tags['dint_tag'][3].value = 1
	prj.controller.tags['dint_tag'][2].description = 'this is bit 2'


Booleans

Like integers, BOOL data types accept integer values, albeit only 0 or 1.

Floats

REAL data types use floating point values. If an integer value is desired,
it must first be converted to a float before assignment or a TypeError will
be raised. Infinite and not-a-number values may not be used.


Structures

Structured data types include UDTs and built-ins such as TIMER. Individual members are accessed using the member's name as an index as follows:

::

prj.controller.tags['timer']['PRE'].value = 100
prj.controller.tags['timer']['DN'].description = 'done bit'

An iterable set of member identifiers is available with the names attribute:

::

>>> prj.controller.tags['timer'].names
['PRE', 'ACC', 'TT', 'EN', 'DN']

Accessing the value of the structure as a whole is also possible using dictionaries keyed by member name.

::

d = {'PRE':0, 'ACC':0, 'EN':0, 'TT':0, 'DN':0}
prj.controller.tags['timer'].value = d

Arrays

Array elements are accessed with standard index notation using integer
indices. Multidimensional arrays use a series of indices, each within their
own bracket as opposed to the comma-separated style of RSLogix.

::

	>>> prj.controller.tags['single_dim_array'][3].value = 16
	>>> prj.controller.tags['multi_dim_array'][2][5].description
	'This is multi_dim_array[2,5]'

The value of entire array is available through the value attribute using
lists. Multidimensional arrays use lists of lists and arrays of complex data
types are supported, for example an array of UDTs is a list of dicts.

::

	>>> l = [0, 1, 2, 3, 4]
	>>> prj.controller.tags['single_dim_array'].value = l
	>>> prj.controller.tags['multi_dim_array'].value
	[[0, 1], [2, 3], [4, 5]]
	

An array's dimensions may be read with the shape attribute, which returns
a tuple containing the size of each dimension. The following example shows
output for a tag of type DINT[4,3,2]. Note the tuple's reversed display order
as the number of elements in DimX is placed in shape[X].

::

	>>> prj.controller.tags['array'].shape
	(2, 3, 4)


Arrays may also be resized by assigning the shape attribute to a new set
of dimensions. Keep in mind the reversed appearance of dimensions described
above. Specifying a shape tuple of (x, y, z) will yield an array sized as
if Dim0=x, Dim1=y, and Dim2=z were used in the Logix tag dialog. Also the
array's element values and descriptions are undefined following a resize
operation, even if the new shape is a subset of the original. If original
content needs to be retained across a resize, it should be copied to
separate variables before assigning a new shape.

::

        >>> prj.controller.tags['DINT_array'].value
        [0, 1, 2, 3]
        >>> prj.controller.tags['DINT_array'].shape = (2, 2)
        >>> prj.controller.tags['DINT_array'].value
        [[0, 0], [0, 0]]


Alias Tags

Alias tags have two available attributes:

description Same as the description attribute of a regular tag.

alias_for A string containing the name of the tag the alias points to. The L5X module does not ensure the target tag exists if the alias_for attribute is altered. Changing the alias_for attribute removes any operand comments the original alias contained. For example, if the alias points to a timer and the alias contained a comment for the PRE member, changing the alias to point to a new tag will remove that comment even if the new tag is also a timer. This does not apply to any comments in the target tags; only the alias comments are affected.

::

    >> prj.controller.tags['alias'].description
    'Tag description'
    >> prj.controller.tags['alias'].alias_for = 'target_tag'

No other attributes, such as value, are implemented for alias tags, nor can they be indexed to access members of the target data type.

Message Tags

While message tags are outwardly similar to `Structures`_,
message tags have only ``description`` and ``parameters`` attributes;
they do not contain any other attributes, such as
``value`` or ``names``. The ``parameters`` attribute provides access to
settings found in the ``MSG`` instruction configuration dialog, presented
as a dictionary with both keys and values as strings. This dictionary must
be modified in-place to alter the L5X project, i.e., change the values of
existing keys; do not assign the ``parameters`` attribute to a different value.

::

        >> prj.controller.tags['msgtag'].parameters['MessageType']
        'CIP Data Table Read'
        >> prj.controller.tags['msgtag'].parameters['RemoteElement'] = 'srctag'

The set of available parameters varies based on the configured message type,
and some keys to not exactly match the names displayed in the ``MSG``
instruction configuration dialog, so the recommended approach is to create
the initial configuration with RSLogix, then use the L5X package to examine
and alter existing parameters.


Modules
-------------------------

The project's modules attribute provides access to modules defined in the
I/O Configuration tree. A list of modules can be obtained with the names
attribute.

::

	>> prj.modules.names
	['Controller', 'DOUT1', 'ENBT']

Each module is comprised of a set of communication ports identified by
a unique integer. Ports feature a read-only type attribute to query the
interface type and a read-write address attribute to get or set the
type-specific address. A typical example for manipulating the IP
address of an Ethernet port, which is usually port 2:

::

	>> prj.modules['ENBT'].ports[2].type
	'Ethernet'
	>> prj.modules['ENBT'].ports[2].address = '192.168.0.1'

Ports configured for network address translation(NAT) can access the NAT
address through the nat_address attribute. NAT addresses can only be
read or altered by the L5X module, not enabled or disabled.
In other wo