CompatcDAQ 9174 with 9215 simultaneous tasks?

[RVallieu]

If we have a C-DAQ 9174 or 9178 with 9215 modules can we run separate AI tasks simultaneously?

We want to be able to measure independently tested devices each with their own start/stop time and being able to run 8 independent DAQmx tasks at once would really simplify things.  I realize I might have to go with two c-DAQ-9174 and 2 9215 cards for 8 channels of independent tasks - I just want to know if this is possible on this chassis?

Thank you

[Jeff-P]

Hi Ryan,

Those two cDAQ chassis both have 4 counters, however there are only three available to analog input, so you can only have three independant analog input tasks on each chassis. Do you need to have hardware timing on all your tasks? Because if you use software timing or if you share counters between the tasks, it is possible to read from the 8 analog inputs on a single chassis.

Regards,

[John_P1]

In addition to only being allowed 3 analog input tasks per chassis, you can only have 1 analog input task per module.  This limitation actually applies to both hardware-timed and software-timed AI tasks.  The number of counters on the chassis is actually not relevant--the analog input timing engines use their own dedicated counters to divide down the internal timebase.

So to run 8 independent AI tasks you would need a minimum of 3 chassis and 8 modules.  Of course, if you can start and stop tasks such that you do not exceed 3 tasks per chassis and 1 task per module then you could have more tasks, but I wouldn't call these independent AI tasks at this point.

One alternative might be to just acquire from all of your channels continuously and only report/keep the data that you are interested in.

Best Regards,