Toshiba T2N - Manual (Page 202)

User's manual 189
4. I/O Allocation
The state of external input signals inputted to T2N input modules is read
via the input registers/devices (XW/X or IW/I) when scan control is
executed. On the other hand, the output data determined in user
program execution are outputted to output modules via output registers/
devices (YW/Y or OW/O) and outputs from the output modules to
external loads are based on these data.
Input/output allocation is the execution of mapping between input
registers/devices and input modules and of mapping between output
registers/devices and output modules. In other words, physical devices
called I/O modules are allocated to logic devices called registers/devices.
Input registers/devices and output registers/devices do not use their own
independent memory areas. They use a series of memory areas which
can be said to be input/output registers/devices (a register address
range of 128words from 000 to 127).
By executing input/output allocation, function type determination is
carried out by making addresses allocated to input modules input
registers/devices and addresses allocated to output modules output
registers/devices.
Note) Addresses not allocated to I/O modules are output (YW)
internally.
4.1
Overview
Input/Output Registers
Input/Output Registers
Input/output
allocation
execution
32-point input
16-point output
16-point output
Input signal ‘A’
Input signal ‘B’
Output signal ‘C’
Output signal ‘D’
I/O Modules