Total counter tasks c-DAQ 9178

[RuedigerSmooth]

Hello,

I'm currently using an NI c-DAQ 9178 with different cards to measure the electrical and hydraulic behavior of ec-pumps.

I’m using two 9361 and one 9474 card for counter tasks. For example, one 9361 is used to count the signal created by the flow meter. The 9474 is used to create a PWM Signal for the ECU of the ec-pump. So now to my problem:

Does every counter task need one timer of the c-DAQ 9178?

As far as my knowledge goes, the c-DAQ 9178 has 4 timers. Which would mean that after just 4 counter tasks in my VI the c-DAQ 9178 would have reached its limits?

Thanks for your help!

[PeterFoerster]

Hi Rüdiger,

normally you'd be right about a limit of 4 timing tasks. However, the 9361 is a timing module that addresses that shortcoming and it allows for more counters than the 9178 would allow. From the product site:

The NI‑9361 is a differential or single-ended input module. With this module, you can expand beyond the four counters in CompactDAQ to reach up to 64 counters per 8‑slot chassis. You can configure each channel to read a single pulse train or combine them to read up to four incremental encoders.

Is this working for you? Have you tried to just use 5 counters?

[RuedigerSmooth]

Hi PeterFoerster,

thanks for your answer!
So just to clarify for me: The NI 9361 Module increases my total number of timers?  
For me the total concept of timer for counter tasks is not really understood. 

If every module which would require a counter task has its own timer, why does the c-DAQ still come with 4 timer?

For me its important to know because we want to expand our system and I want to be sure that every thing than works as planed.
Thanks again for your help!

[Kevin_Price · Accepted solution]

Counter/timers can be programmed for a variety of behaviors, but each counter/timer can produce only one behavior at a time.  If you're using one for pulse generation it can't also be used for edge counting.  If you're measuring frequency, you can't also generate a pulse.  Etc.

Most cDAQ modules do *not* have any additional counter/timers of their own.  They depend on the counters built into the chassis.  The NI 9361 module is an exception as it's a special-purpose module designed specifically to provide more counter/timer I/O. 

Specific answers: when you configure a counter task for the 9474, you'll be using a counter from within the chassis and the 9474 acts as connectivity between that counter and the outside world.   When you configure a counter task for the 9361, you'll be using one of the counters built into the 9361 itself rather than one of the ones from the chassis.

-Kevin P