programming analoge module(mitsubishi)

hi how are you, thanks to you i,m starting to create my own program now. i have two questions??

i,m using a melsec FX2n PLC
i,m now trying to program a FX2n -2AD. this module is used to convert two anlog signals to digitals one. the problem is that in the programming manuals there are two fuction which can do this ,
1 THe "FROM" and the "to"
2 the RD3a

1 can anyone help me with a sample program using the RD3A fucntion

FROM is used to copy data from module to PLC memory so your
program can use it.
TO is used to send data to module for example to configure it
or to write values to analog outputs.

Take a good look at the Buffer memory settings.

You will find them in the booklet that came with the PLC.

Every buffer has its own meanning.

In some you will activate a chanel.
In others you will read the realtime value or the average value. This average will be based on scans or time and of course these settings are written TO some buffers.

So to read a value you will use FROM and to qwrite to a buffer you will use TO.