Synchronize PXI Controller Timestamp with PXI Clk-10

[KoBe]

Hi,

i have a big problem: im my project I need to evaluate the difference between the RT timestamp and the Read X-NET CAN Frame Timestamp to sort my incoming data.

System: PXIe-8100 RT Controller; PXIe-1071 Chassis; PXI-8512 CAN Card

Unfortunately it came out, that these timestamps are not synchronized and have a different clock speed. I after some time it seems like I would receive the CAN messages before I trigger the external Hardware to send me a CAN frame.

I asked the support, if connecting the CAN Card Mastertimestamp with Clk-10 of my PXI would synchronize both clocks, but i was told, that the RT timestamp is software and can not be synchronized with any signal off the PXI backplane.

I hope really that this i not all of the truth, maybe there is some kind of workaround to synchronize the RT Timestamp with a fixed PXI clock. If there would be a fixed offset between RT Timestamp and the X-NET Timestamp I can correct it by software, but the varying offset at the moment is a serious problem for me.

Hopefully someone has I great idea!

[viSci]

Maybe this might give you some ideas...

http://forums.ni.com...time/m-p/392827

Also heard that cRIO CAN automatically synchronizes its timestamp with the cRIO VxWorks system Timestamp. So I guess

there should be no reason why it could not be done for Pharlap based RT.

"Moreover, on a CompactRIO system, the module’s timebase is corrected

for drift with respect to the RT controller’s timebase, allowing the

capability to correlate data with other modules in the chassis." - page 3-19 of the NI-XNET Hardware Overview Manual