The NX-SID800 is a common device choice when designing an NX-Safety System, mainly due to the higher number of safety inputs it has to offer. It's important to note however, that some OMRON safety input devices are not compatible with this NX-Unit. The table below highlights that OMRON Special Special Safety Input Devices cannot be connected to this NX-Unit. This information can also be found in the NX-SI/SO datasheet.
| Model | Number of safety input points |
Number of test output points |
Internal I/O common | Rated input voltage | OMRON Special Safety Input Devices |
Number of safety slave connections |
I/O refreshing method |
| NX-SIH400 | 4 points | 2 points | Sinking inputs (PNP) | 24 VDC | Can be connected. | 1 | Free-Run refreshing |
| NX-SID800 | 8 points | 2 points | puts (PNP) | 24 VDC | Cannot be connected. | 1 | Free-Run refreshing |
The following table shows the OMRON Special Safety Input Devices that the previous table refers to.
| Category | Series |
| OMRON Single-beam Safety Sensors* | E3ZS and E3FS |
| OMRON Non-contact Door Switches | D40A-2 |
| D40Z | |
| D40A | |
| OMRON Safety Mats* | UM and UMA |
| OMRON Safety Edges* | SGE (4-wire connection) |
*OMRON Safety Mats, OMRON Safety Edges, and the E3FS Single-beam Safety Sensors have been discontinued and are no longer available to purchase.
Adding these devices to SYSMAC Studio.

The items listed in the previous table can be found in your Toolbox when viewing the Parameters for the NX-safety unit.
Safety Controller → Communications → Safety → Safety I/O → Unit[X] → Parameters.
When attempting to add one of these devices to an NX-SID800 you will get a build error stating that the device is not supported by the slave unit.
These devices must be connected to an NX-SIH400


Further information regarding NX-Safety units may be found in the NX-Series Safety Control Unit User's Manual (Z930-E1-27)