Reading float values about pylsv2

[drunsinn]

Hello @orkhands,

thanks for the feedback! I will add your software version to my list :-)

I am sorry to say that as far as i know TNCscope is using the DNC library instead of LSV2. I have done quite a bit of searching and analysis with Wireshark but DNC is quite a bit harder to decode than LSV2 which is for the most part just plain text without any encoding.

On the upside it seems that there is indeed a problem in pyLSV2 in reading from the memory address. Currently it is using the telegram R_MB to read values from memory, on a TNC 640 this has worked just fine and i assumed it would also work on an iTNC as i got good values for everything i checked. This seems to not be the case! After checking again with TNCcmd again I found the command GETVALUE which i always ignored as it has some strict limitations:
Availability: iTNC 530 as of 34049x 03 and 60642x 01 or TNC 640 as of 34059x 01 (only with TNCcmdPlus)
This command uses the telegram R_DP to read values by using some kind of special path like \PLC\memory\M\100.

I created a new branch to try reading via R_DP and it seems to work at least for one value :-) check it out here: data_path
It adds the new function read_data_path(path) which takes a string like TNCcmd. This is not ready yet as i have not been able to figure out the meaning of all the byte values sent and revived. If i have time i will take a look next weekend on what i can figure out. If you are interested you can take a look yourself, Pull requests are always welcome!