Table Of Contents

Using Onboard Counters

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    Last Modified: August 20, 2020

    CompactDAQ chassis have onboard counters you can configure and use similarly to counter module channels. An onboard counter looks like a module in FlexLogger, but it is not a module and functions differently from a counter module, such as the NI 9361.

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    Note  

    To use onboard counters, navigate to File»Preferences»Preview Features and select Enable the use of onboard counters for cDAQ chassis.

    When configuring and using onboard counters, keep in mind the following functionality:
    • cDAQ chassis require digital modules—To connect to the onboard counter of a cDAQ chassis, you must connect a digital device to the chassis. For more information about supported digital modules, refer to "Digital I/O Considerations for C Series Devices" in NI-DAQmx Help matching your driver version.
    • You must specify the input terminal—You may have multiple options to use as the input terminal. You must specify which digital module you want to use as the input terminal.
    • You cannot use an onboard counter to create an internal sample clock—Onboard counters cannot divide down their timebase to create an internal sample clock. FlexLogger uses the Frequency Output (FREQ OUT) signal to supply the clock source.
    • Onboard counters have fixed supported sample rates—Sample rates cannot synchronize with anything else on the board and use a fixed number of sample rates based on the Frequency Output signal. The signal uses the 20 MHz, 10 MHz (20 MHz divided by 2), or 100 kHz Timebase, which you can divide by an integer from 1 to 16.

    You can find more information about onboard counters and the Frequency Output signal in the cDAQ chassis user manuals under Counters»Counter Timing Engine and Counters»Counter Output Applications»Frequency Generation.


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