Omron TJ2-MC64 - PROGRAMMING Programming Manual page 278

Examples and tips
inputs are active (ON) when a 24 VDC signal is applied to them. When
you read them, they return their current status. Use the command IN to
read these inputs.
• Digital inputs 16 - 31.
These outputs are software inputs only. They do not physically exist on
the TJ2-MC64, but you can read them. You use them mostly in BASIC
programs to accomplish some control sequences that require inputs
which do not need to be physical. Use the command IN to read these
inputs.
• Digital inputs 32 - 255.
These inputs are physically present only if additional digital I/O units are
connected to the TJ2-MC64 via the MECHATROLINK-II bus. If you read
them if they do not physically exist (the I/O units are not connected), they
return 0. Use the command IN to read these inputs.
All inputs are unique to the controller. They are not accessed per axis.
PROGRAMMING MANUAL 272