The remote input device and the remote output device cannot be assigned in network parameters.
To assign them, create a program for updating data.

For details, refer to the following.
　Section 8.3 in the FX3U-16CCL-M User's Manual (Manual number: JY997D43601)
　　
The following programmable controllers and GX Works2 support some items, such as mode setting, in network parameters.
FX3G/FX3GC series: Ver. 2.00 or later (GX Works2: Ver. 1.87R or later)
FX3U/FX3UC series: Ver. 3.10 or later (GX Works2: Ver. 1.73B or later)
* The version of programmable controllers can be checked with the last three digits of the data in D8001/D8101.
* When connecting the FX3U-16CCL-M to a programmable controller of the FX3GC/FX3UC series, the FX2NC-CNV-IF or FX3UC-1PS-5V is required.

For details on items which can be set in network parameters, refer to the following.
　Section 8.4.1 in the FX3U-16CCL-M User's Manual (Manual number: JY997D43601)