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Shared signal connection while using all counters on NI-9411 corrupts data?

Currently have 3 quadratic encoders (w/o z-ref) wired into NI9411 counter inputs.  Allows me to get position and rpm with same signal.  However, the counter inputs shared a common wiring hub and therefore interferes with each others readings.  How can I solve this?  I am using Daqmx and the connections are provided to me through the software.  I can hook up each encoder individually and they work fine on their given ports but cannot run them all simultaneusly. 

Example: Cntr 0 uses terminals PFI0 and PFI2

              Ctnr 1 uses terminals PFI3 and PFI5

               Cntr 2 uses terminals PFI2 and PFI1

               Cntr 3 uses terminals PFI5 and PFI4

As you can see there are shared connections points whcich would only allow me to use two counters simultaneusly when I need to use three. 

Any help would be great.

 

Thanks,

-P

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Hi HDtech,

 

Unfortunately you won't be able to take more than two counter inputs at a time with this module. Although it allows some counter functionality, this module is primarily used for industrial DI functionality. If you need more counter inputs you could get another 9411, or you can get a module more dedicated to counter inputs such as the 9402 which can take four counter inputs. Alternatively, if you have other modules in your cDAQ chassis you might be able to make use of one of them for the third counter input channel.

 

Hopefully this helps,

 

Chris G

Applications Engineer
National Instruments
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