I am using OpenPLC to query some slaves and I want to process the obtained values using a function that includes reading from a text file. This feature is not offered by a structure text, so I went to incorporate this function within a modbus_master.cpp file. I found the part that reads a holding register in querySlaveDevices and for simple testing, I assign a constant number to the holding register.
But when I run the PLC, the monitor page keeps giving me the value received from the slave. Did I miss something? Should I compile the OpenPLC code through the terminal to get the update?