ljean
commented
6 years ago Hello Peter, Congratulations for this first success. Of course, your working code can be integrated into an app and add more feature. modbus_tk has a hook mechanism which allows to integrate specific features on some events like for example when a request is received.
You can look at this example which use the hook mechanism : https://github.com/ljean/modbus-tk/blob/master/examples/tcpmaster_example.py
Here is the full list of hooks : https://github.com/ljean/modbus-tk/blob/master/modbus_tk/hooks.py
Another possibility is to have a background task in charge of the calculations. You can have a look at this other example : https://github.com/ljean/modbus-tk/blob/master/examples/modbus_system_monitor.py
For sure, you'll have to learn a few things on Python to make this work, but Python is a very nice language and it worths to be learned.
I hope it helps Best luc
aztecdes
I have successfully used the master and slave to write and read both coils and holding registers using the master to carry out these requests using RS585 .This is great! However..I need to be able to do more than this..Basically I need to incorporate the modbus tk slave program into a python program in a Raspberry pi where I can take the data sent to the slave program/ device ( The holding registers or cioils)and then copy it into a variable list or array..then I conduct some calculations etc and then write the new data into back into the modsbus slave registers ( diferent from the location read from) ..them write to a coil to signify that the new data is ready to be read by the master.
I am very new to Python..so apologize in advance..but would very much appreciate guidance on how to read and write to and from the coils and holding registers from within the slave program itself? THANK YOU. Peter