3.3.1 Notes on S7-200
When creating a data link to S7-200 it is not allowed to have more than one
connection parameterised in the load_tool function.
The connection is initialised by means of the load_tool function. This is
followed by the user specific part, where you may only call the as200_......
functions from the adaptor (see also Para. 4.1.2 “Basic Functions for Data
Transfer S7-200 “). When you wish to end your program, it is required to deinitialise
the connections by means of the unload_tool function.