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8 Digital Mixed I/O Units
NX-series Digital I/O Unit User’s Manual (W521)
8-4 Function
8
8-4-1 Input Functions
8-4 Function
This section describes the Digital Mixed I/O Unit functions.
Refer to the specifications of each model in A-1 Data Sheet on page A-2 for details on the functions.
8-4-1 Input Functions
Function name Description Reference
Free-Run Refreshing With this I/O refreshing method, the refresh cycle of the NX
bus and the I/O refresh cycles of the NX Units are asynchro-
nous.
5-2-4 Free-Run
Refreshing on
page 5-8
Synchronous I/O Refresh-
ing
With this I/O refreshing method, the timing to read inputs or to
refresh outputs is synchronized on a fixed interval between
more than one NX Unit connected to a CPU Unit.
In addition, with this I/O refreshing method, the timing to read
inputs or to refresh outputs is synchronized on a fixed interval
between more than one NX Unit on more than one Slave Ter-
minal.
5-2-5 Synchro-
nous Input
Refreshing on
page 5-12
Input Filter This function eliminates the chattering or the noises from input
signals.
It is used to prevent the error reading due to the noises. You
can set the filter time constant.
6-4-2 Input Filter
on page 6-14
8-4-2 Output Functions
Function name Description Reference
Free-Run Refreshing With this I/O refreshing method, the refresh cycle of the NX
bus and the I/O refresh cycles of the NX Units are asynchro-
nous.
5-2-4 Free-Run
Refreshing on
page 5-8
Synchronous I/O Refresh-
ing
With this I/O refreshing method, the timing to read inputs or to
refresh outputs is synchronized on a fixed interval between
more than one NX Unit connected to a CPU Unit.
In addition, with this I/O refreshing method, the timing to read
inputs or to refresh outputs is synchronized on a fixed interval
between more than one NX Unit on more than one Slave Ter-
minal.
5-2-5 Synchro-
nous Input
Refreshing on
page 5-12
Load Rejection Output
Setting
A function that performs the preset output operation when the
Digital Output Unit cannot receive output data due to an NX
bus error or CPU Unit watchdog timer error, in the case of
Units connected to a CPU Unit.
A function that performs the preset output operation when the
Digital Output Unit cannot receive output data due to a host
error on the Communications Coupler Unit or an error on the
NX bus, in the case of Slave Terminals.
7-4-2 Load Rejec-
tion Output Setting
on page 7-13
Load Short-circuit Protec-
tion
A function in which the output will turn OFF to protect the out-
put circuit when an overload or load short-circuit occurs due to
a failure of the connected external devices.
7-4-3 Load
Short-circuit Pro-
tection on page
7-17
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