Copley Motion Objects and LV Real Time

[Maciekdp]

I have an NI PCI CAN 2 card installed in a real time system.  I'd like to use it to control a Xenus amplifier from Copley Inc.  It seems that CMO objects are not supported.  Has anyone had any luck with it?

Maciek

[Justin_E]

Hi Maciekdp,

CMO objects are built to communicate over a CANopen network. We produce a CANopen Library for use in LabVIEW (which can be found here : http://sine.ni.com/nips/cds/view/p/lang/en/nid/202614). The library that we supply has support for LabVIEW Real-Time only with Series 2 PXI high-speed CAN interfaces. Thus, unfortunately it looks like you will not be able to communicate with your PCI CAN 2 card over a CANopen network (in this case, CMO) in your real-time system. I would also double-check with Copley to see if they can give you any information, as CMO is their product.

[Maciekdp]

Hi,

We actually borrowed the card from NI to see how well it would work.  At this point we could attempt to try the latest card, provided that the communication is fast enough.  After posting my question I learned that CAN is limited to only 500 Hz.  Is this due to the nature of CAN?  Is the max. transfer rate the same in RTOS?

Maciek

[Justin_E]

Hey Maciekdp,

I'm not sure if I completely understand what you mean when you say that CAN is limited to 500Hz. The baud rate set in a CAN device sets the speed that data is transmitted across the bus, and for a PCI CAN card the max baud rate ranges across cards/setups from 33.3kbps to 1Mbps (this data was found in the NI-CAN Hardware and Software Manual, Appendix E found here : http://www.ni.com/pdf/manuals/370289k.pdf ). In a Real-Time system, the limitation to data transfer speed is based on that maximum baud rate, and not necessarily the operating system. The maximum transfer rate between CAN devices in a Real-Time Operating System is also based on this maximum baud rate. 

Message Edited by Justin E on 02-10-2009 03:22 PM