libmodbus tcp on arm linux

Hi There,

i am working on a modbus project which is over tcp. i am using libmodbus libraries from Gitlibmodbus. as per the requirements i have to enable the registers individually.

to do that i am using modbus_write_register to write to a register and modbus_read_registers to read from the registers, which works fine as long as i just write to the register and readback immediately.
but where i struck is when i enable one of the registers it should run the test for sometime and read the value while test is running/after completed to client window.

i couldn’t figure out how i could do this. any ideas on how do i proceed with this is much appreciated.i will post the program if it is required

Thanks in advance.