Is there a way to attach NI 9148 Expansion Chassis to cRIO in Scan Mode?

[JimMacD]

The "Getting Started with the NI 9148 Ethernet RIO Expansion Chassis" whitepaper indicates that the 9148 chassis is compatible with the cRIO controller series: http://zone.ni.com/devzone/cda/tut/p/id/11703

I'm having trouble finding information on connecting this expansion chassis to a cRIO, and if it can be done while accessing the IO in Scan Mode. Does anyone have information on this?

Thanks

[Blayne_K]

Hello JimMacD,

The process of adding a 9148 ethernet expansion chassis to a cRIO controller would be the same process in the LabVIEW project explorer as adding a standard cRIO chassis, namely right clicking on the CompactRIO RT Controller -> New -> Targets and Devices -> Chassis Type (in your case 9148). The project configuration tree might look something like the following:

Additionally, you will be able to read and write successfully to various cRIO modules in scan mode on the 9148. The following KnowledgeBase article covers which modules will work with the 9148 and which mode (FPGA vs Scan) will apply to each module.

Regards, 

Blayne K

[JimMacD]

Blayne,

When I try to add a second chassis to an existing cRIO in the project, there is a message saying "only one chassis per controller". My hope was to have both the attached cRIO backplane and a 9148 extension (for up to 16 modules on one cRIO). It seems like this should be possible, what am I doing wrong?

-JimM

[Blayne_K]

Hi JimM,

Unfortunately, you will be unable to add more than one chassis to the cRIO controller as you may have intended with the 9148. That being said, you could add the 9148 to your project if its connected through an ethernet network and share data via Network Published IO Variables if you wish to pass data back to the cRIO controller, or to a dedicated PC. Perhaps, the functionality you may have been intending could have been achieved with an EtherCat expansion chassis like the 9144. The 9144 would allow you to daisy chain multiple chassis and greatly expand a given systems IO capabilities.

Best,

Blayne K

[JimMacD]

Blayne,

You are correct, I was hoping to use it like the 9144 Ethercat Chassis. The one down side to the Ethercat setup is that it does not allow Port 2 on the cRIO to be used as a standard TCP/IP Port: http://zone.ni.com/devzone/cda/tut/p/id/10555 (see: Configuring the Master Controller). I normally use this port to setup a Secondary network to talk Modbus TCP/IP to stand-alone process controllers (Temperature controllers, PLCs, etc...) that I do not want to be on the main subnet (Port 1).

-Jim