9-2
Using negative logic for programmable I/O terminals
The negative logic signaling system can be used for digital input terminals and transistor output
terminals by setting the function code data specifying the properties for those terminals. Negative
logic refers to the inverted ON/OFF (logical value 1 (true)/0 (false)) state of input or output signals. An
active-ON signal (the function takes effect if the terminal is short-circuited.) in the normal logic
system is functionally equivalent to active-OFF signal (the function takes effect if the terminal is
opened.) in the negative logic system. Active-ON signals can be switched to active-OFF signals, and
vice versa, with the function code data setting, except some signals.
To set the negative logic system for an input or output terminal, enter data of 1000s (by adding 1000 to
the data for the normal logic) in the corresponding function code.
Example: "Coast to a stop" command BX assigned to any of digital input terminals [X1] to [X3] using
any of function codes E01 through E03.
Function code data BX
7 Turning BX ON causes the motor to coast to a stop. (Active-ON)
1007 Turning BX OFF causes the motor to coast to a stop. (Active-OFF)
Limitation of data displayed on the LED monitor
Only four digits can be displayed on the 4-digit LED monitor. If you enter more than 4 digits of data
valid for a function code, any digits after the 4th digit of the set data will not be displayed, however
they will be processed correctly.
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