pyads 2.0.0

Python wrapper for TwinCAT ADS library

This is a python wrapper for TwinCATs ADS library. It provides python functions for communicating with TwinCAT devices. pyads uses the C API AdsDLL.dll. The documentation for the ADS API is available on infosys.beckhoff.com.

Changelog

Version 2.0.0

I wanted to make the Wrapper more pythonic so I created a new module named pyads.ads that contains all the functions from pyads.pyads but in a more pythonic way. You can still access the old functions by using the pyads.pyads module.

Improvements:

• more pythonic function names (e.g. ‘write’ instead of ‘adsSyncWrite’)

• easier handling of reading and writing Strings

• no error codes, if errors occur an Exception with the error code will be raised

Examples

Open port and create a AmsAddr object for remote machine.

>>> import pyads
>>> pyads.open_port()
32828
>>> pyads.get_local_address()
<AmsAddress 192.168.0.109.1.1:32828>
>>> adr = pyads.AmsAddr('5.33.160.54.1.1', 851)

You can read and write a variable by name from a remote machine.

>>> pyads.read_by_name(adr, 'global.bool_value', pyads.PLCTYPE_BOOL)
True
>>> pyads.write_by_name(adr, 'global.bool_value', False, pyads.PLCTYPE_BOOL)
>>> pyads.read_by_name(adr, 'global.bool_value', pyads.PLCTYPE_BOOL)
False

If the name could not be found an Exception containing the error message and ADS Error number is raised.

>>> pyads.read_by_name(adr, 'global.wrong_name', pyads.PLCTYPE_BOOL)
ADSError: ADSError: symbol not found (1808)

Reading and writing Strings is now easier as you don’ t have to supply the length of a string anymore. For reading strings the maximum buffer length is 1024.

>>> pyads.read_by_name(adr, 'global.sample_string', pyads.PLCTYPE_STRING)
'Hello World'
>>> pyads.write_by_name(adr, 'global.sample_string', 'abc', pyads.PLCTYPE_STRING)
>>> pyads.read_by_name(adr, 'global.sample_string', pyads.PLCTYPE_STRING)
'abc'

Setting the ADS state and machine state.

>>> pyads.write_control(adr, pyads.ADSSTATE_STOP, 0, 0)

Toggle bitsize variables by address.

>>> data = pyads.read(adr, INDEXGROUP_MEMORYBIT, 100*8 + 0, PLCTYPE_BOOL)
>>> pyads.write(adr, INDEXGROUP_MEMORYBIT, 100*8 + 0, not data)

Read and write udint variable by address.

>>> pyads.write(adr, INDEXGROUP_MEMORYBYTE, 0, 65536, PLCTYPE_UDINT)
>>> pyads.read(adr, INDEXGROUP_MEMORYBYTE, 0, PLCTYPE_UDINT)
65536

Finally close the ADS port.

>>> pyads.close_port()