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74 T1-16S User’s Manual
6. Programming Information

6.1 Devices and registers

The T1-16S program consists of bit-based instructions that handle ON/OFF
information, such as contact and coil instructions, and register-based (16-bit)
instructions, such as those for data transfer and arithmetic operations.
Devices are used to store the ON/OFF information of contacts and coils, and registers
are used to store 16-bit data.
Devices are divided into six types:
X External input devices
Y External output devices
R Auxiliary relay devices
S Special devices
T. Timer devices
C. Counter devices
Registers are divided into eight types:
XW External input registers
YW External output registers
RW Auxiliary relay registers
SW Special registers
T Time r registers
C Counter registers
D Data registers
I, J, K Index registers

Device and register numbers

X devices share the same memory area as XW registers. Devic e X004, for example ,
represents the number 4 bit in the XW00 register.
Bit position / Number
(MSB) (LSB)
FEDCBA9876543210
XW00 1
X004
Thus, "X004 is ON" means that bit number 4 of XW00 is 1.
Y, R, and S devices work in a similar manner.