How to use the PXI's 10MHz backplane clock to synchronize two or more 6031E boards?

[Chienwei]

Hi,

I'm trying to use two 6031E boards to acquire multiple channels Analog Inputs, and I'd like to sync them with the PXI backplane clock (not the RTSI bus). I found an example from NI, "Two E-Series Shared ScanClk.vi", and modified it a bit. But I'm wondering if the two boards must have the same acqusition rate? e.g. Can I have 1 board acquiring at 1kHz while the other one at 20Hz? and if yes, how do I do it?

Your input will be very much appreciated. Thanks!

Dan

[Russell]

Unfortunately, E Series boards cannot synchronize with the 10 MHz PXI backplane clock. They do, however, have access to the PXI trigger lines, which are basically the RTSI lines. Except for line 6 which is the star trigger line. They can only read from this line.

The example program you have selected will definitely be part of your solution. It allows you to share the scan clock timing signal between two boards. If you would like the slave board to acquire at a slower scan rate, you could always route the master's scan clock to one of the slave's on-board counters which can act as a frequency divider. The output of this counter can become the new slower scan clock for the slave board. Use the Generate Pulse Train shipping example VI as your frequency d
ivider. Finally, make sure you route the signals appropriately and you'll be in business.

I hope this helps!

Russell McMurtrey
Applications Engineer
National Instruments
http://www.ni.com/support

[Chienwei]

Hi Russell,

Thank you very much for your input. One thing you mentioned is that I can use on-board counters? But the "counter group config" VI does not support E-series boards according to the VI description? So can you give me some hint on which VIs I should use?

Thanks

Dan