Niagara Remote Input Output, similar to the equivalent NDIO (or Ndio) “Niagara Direct Input Output” driver that is the station interface to other types of I/O hardware. Note throughout this document, capitalization of NRIO is typically limited to the leading “N”, as in “Nrio proxy point”. This reflects actual Niagara component and view names, such as NrioNetwork, Nrio16Module, Nrio Device Manager, and so on. Occasionally, the lowercase “nrio” is used when referring to the actual nrio module (as in .jar file).

To start with, each driver supports a different group of I/O hardware. Initially, the Nrio driver is needed only for the “onboard I/O” of a JACE-x02 Express or “M2M JACE”. It will also be used for “remote I/O modules” as they are released. Both drivers use a “low-level daemon” to communicate to I/O processors on I/O hardware. Unlike the I²C bus used by the Ndio daemon, the daemon in Nrio uses RS-485, and thus multiple NrioNetworks (each with a separate daemon) are possible on a JACE station—each NrioNetwork requires a specific COM port. Whereas, in Ndio, only one NdioNetwork is supported.

Also, in an NdioNetwork, all “devices” (NdioBoards) are automatically discovered and addressed relative to the physical order of attachment of I/O modules to the parent JACE. However, when RS-485 connected remote I/O devices (NrioModules) are discovered under an NrioNetwork, this proximity order does not exist. Instead, the driver automatically assigns consecutive addresses, and provides a “wink” action on each device so you can positively associate the discovered component to the actual physical I/O module.

Apart from these “network and device” differences, at the proxy point level there is little difference between Nrio and Ndio. Nrio and Ndio proxy points that represent hardware I/O points are nearly identical. There are fewer components in the Nrio palette, but the manager views in the Nrio driver allow you to create whatever new components are needed—even if working with the Nrio hardware offline.

In the Nrio Point Manager if you add a VoltageInputPoint, ResistiveInputPoint, or ThermistorInputPoint and change the point’s Facets to another category of units, you typically see this fault status. This happens because those types of proxy points are automatically added with a “LinearCalibrationExt”, and its “units” property does not automatically stay in sync with the proxy point’s Facets.

To clear this fault status, go to the property sheet of the LinearCalibrationExt under the point, and assign the identical units as you did in the proxy point’s Facets. Alternatively, you could simply delete the point extension, but that would remove the “Offset” (calibration) utility that it provides.

Note this fault status happens most for VoltageInputPoints, and rarely (if ever) for a ThermistorInputPoint—because its units should always remain temperature, even if changing between ˚C and ˚F.