6.1.1 Input/Output Variables

In do, dob, dow, dol, and dof, the suffixes b, w, l, and f mean “byte,” “word,” “long,” and “float,” respectively, and all are signed values. These are not separate memory spaces and represent the same 960-byte space just with different data types. For example, do[1~16], dob[1~2], and dow[1] are all the same output signals.

If a value is assigned to an output variable that starts with “do,” I/O signal output will be performed. The I/O signal currently being inputted can be acquired by reading the input variable value that starts with “di.” The do variable can be read and written, but the di variable can only be read.

The FB object name can be omitted as follows.

object name	do notation	fb.do notation
fb0	do0 ~ do959	fb0.do0 ~ fb0.do959
fb1	do960 ~ do1919	fb1.do0 ~ fb1.do959
fb2	do1920 ~ do2879	fb2.do0 ~ fb2.do959
fb3	do2880 ~ do3839	fb3.do0 ~ fb3.do959
fb4	do3840 ~ do4799	fb4.do0 ~ fb4.do959
fb5	do4800 ~ do5759	fb5.do0 ~ fb5.do959
fb6	do5760 ~ do6719	fb6.do0 ~ fb6.do959
fb7	do6720 ~ do7679	fb7.do0 ~ fb7.do959
fb8	do7680 ~ do8639	fb8.do0 ~ fb8.do959
fb9	do8640 ~ do9599	fb9.do0 ~ fb9.do959