LabVIEW, Can I synchronize a cDAQ device (9231) and a CAN device (9862) in the same chassis (9174)

[TulaRen]

If I can, can someone share a sample LabVIEW code?

Thanks.

Ian

[GerdW]

Hi Ren,

in which way do you want to sync those modules?

- Do you want to measure some analog data for each CAN message? Or for specific CAN messages?

- How accurate do you need to sync? ms, µs or ns? (Which CAN baudrate do you use?)

- Your NI9231 uses a delta-sigma ADC, which is hard to sync with other devices. Other kind of ADCs are easier to sync…

[TulaRen]

GerdW,

Thanks for your response. I want to

1) measure a few (10-20) analog data signals for specific CAN messages. The CAN signals are updated at 100Hz rate.

2) start CAN and DAQ at the same time (by the same trigger signal, which I have found doable from the XNET example).

3) An accuracy about 1-2 ms is acceptable. The baudrate is 500kHz.

4) If I cannot sync 9231 with 9862 acquisition from the same clock base, and I just start CAN and DAQ by the same trigger, do you have a feel how long I could run data acquisition before the CAN and analog signals would be out of synch for more than 1-2 ms? module 9231 and 9862 are in the same 9174 chassis.

Thanks.

Ian

[TulaRen]

CAN will be acquiring data at 256Hz, so an synch error of one sample, i.e., 4ms, is acceptable.