6F3B0253
Basic Hardware and Function 77
6. Programming Information
External input devices (X)
These devices (X) indicate the ON/OFF states of external input signals through the
input circuits. External input devices can be used many times in a program.
External output devices (Y)
The external output devices (Y) store the ON/OFF signals that drive the external
devices through the output circuits. They can be used for coils in a program.
External input registers (XW)
These (XW) are 16-bit registers for storing values, which are received from the input
circuits.
External output registers (YW)
These 16-bit registers (YW) are used for storing values, which are sent to the output
circuits.
Auxiliary relay devices and registers (R/RW)
The auxiliary relay devices (R) are used to store intermediate results of sequences.
The auxiliary relay registers (RW) are used to store temporary results of function
instructions. The data in R/RW cannot be output directly to the output circuits. It is
necessary to move the data to Y/YW.
It is possible to make these registers retentive so that they retain data in the event of a
power failure. See section 5.3.
Timer devices and registers (T./T)
The timer registers (T) are used for storing the elapsed time of timer instructions, the
on-delay (TON), off-delay (TOF) and single-shot (SS) timers.
0.01 s base timers and 0.1 s base timers are provided.
Time base T1-16S
0.01 s T000 to T063
0.1 s T064 to T255
The timer devices (T.) work as the output of the timer instructions.
It is possible to specify the T registers as retentive to retain their data in the event of a
power failure. See section 5.3.