NI 9423 Simultaneously get speed, direction and total count of 4 quadrature encoders

[joe4465]

Hi,

I am using the cDAQ-9178 chassis and the 9423 card connected to 4 quadrature encoders. I am programming in C# using the National instruments DAQmx DLL.

I have a few questions:

1. Can I change the PFI connections for each counter? I would like to connect 4 quadrature encoders A&B signals to the module such that:

Encoder 1 A -> PFI0

Encoder 1 B -> PFI1

Encoder 2 A -> PFI2

Encoder 2 B -> PFI3

Encoder 3 A -> PFI4

Encoder 3 B -> PFI5

Encoder 4 A -> PFI6

Encoder 4 B -> PFI7

2. I need to get speed (RPM), direction and count from 4 quadrature encoder simultaneously. Is there a virtual channel that does all of this or do I need to use seperate virtual channels and combine them into one task?

To count I think I should use CIChannels.CreateCountEdgesChannel. To get the speed I think I should use CIChannels.CreateFrequencyChannel. Is this correct?

How would I get direction?

How can I make sure that count goes both up and down when the quadrature encoder direction is reversed? I think I would use the direction to toggle the count up/down?

What is the best way of doing what I need? 

Thanks in advance

Joe

[Rob_Ward]

Dear Joe,

Thank you for posting this; have you been able to make any progress with this issue?  My knowledge of C# is rather limited but I was able to find this community example that you may find useful ( https://decibel.ni.com/content/docs/DOC-16563 ).

Kind Regards,