How to export timebase from a cDAQ chassis 9174 to a cDAQ module 9234?

[Jimpe]

Dear all,

I'm trying to exort the 80MHz  timebase of a cDAQ9174 to a 9230 board and 9234 board by software.

System configuration:

- NI cDAQ 9174 with:

--> Slot 1: 9234 board

--> Slot2: 9230 board

--> Slot 3: 9211 board

--> Slot 4: 9862 board

Software:

LabView 2014

NI DAQmx 14.5

I would like to use the 80 MHz time base of the cDAQ 9184 as the master timebase for the boards 9234 and 9230. Measurements from these two boards must be synchronized and I would like to set the sampling rate to have a measurement every ms. However, the internal clock doesn't allow to set the sampling rate "as I want it to be". There are dedicated values with Fs = Fm/256/n with n between 1 ans 31 (from the board specification).

I tried to use the 80MHz timebase clock with the NI LabView example "Voltage-Continuous Input.vi" but the connection is not allowed

Error: "Requested Sampe clock source is invalid"

I tried to find a way to configure boards on  NI MAX but I have not found a solution there.

Is there a way to connect the 80MHz clock to the 9230 and 9234 boards, or to set the samplig rate so that it's possible to have a measurement every ms?

Thanks for the time you will consider to these questions.

Kind regards.

Jimmy

[=Jean]

Hi,

You can't export this clock. This clock could only (in some case) be used directly by counters (like the M series: http://www.ni.com/tutorial/3615/en/).

But I can't understand your point: both card can reach 51kS/s and 12.8kS/s, rates which are far more than every ms.

If you want to have a measurement every ms, go to 2056kS/s using the 10MHz Timebase and do a decimation on your values (3005S/s is even better).

Hope that helps! 

[Jimpe]

Hi,

thank you for your answer.

The datasheet of the 9230 and 9234 boards say that it's possible to use an external timebase.

I would like to synchronize the measurement of the 2 boards --> No problem with this point.

I know that my boards can reach 51.2 kS/s and 12.8 kS/s, but it means that I don't have a finite number of samples per ms (for 2.048 kS/s, I get 2.048 points / ms) and I want to integrate my measurement on a ms. That's why I would like to use an external timebase for both boards, to synchronize them and to integrate the measurement on 1 ms.

On a PXI 6289 board, I can set the rate to 2 kS/s, so 2 points per ms. This is this kind of behaviour that I'm tryig to get on my system.

Is there a way to do this? Can I use another clock from my cDAQ system 9174 that is shared with the 2 boards?

Thanks for the help.

Best regards.

Jimmy