Encoder with external sample clock cDAQ 9361

[mdwebster]

I'm looking at potentially replacing an old Traditional NIDAQ PCI counter/timer setup with a cDAQ chassis.

The application is counting in 6 quadrature linear encoders using a converted pulsetrain from a rotary encoder as a clock signal so we get spatially arrayed data (instead of the more traditional time based).  Neat idea, but I want to make sure I can duplicate it on modern hardware.  (The conversion is a board that converts each positive or negative transition of A or B to a TTL pulse)

I'm looking at maybe using a cDAQ chassis with a couple of 9361's, but I'm not sure about importing the external clock.  I would put 3 encoders (A/B, no Z) on each of the 9361's (because of the limited number of PFI terminals, you can't put more than 4 encoders on one module).  I tried setting this up as a simulated device and trying to use the left-over 4th counter PFI3 as the external clock source, I get the error -89136 :  

Specified route cannot be satisfied, because the hardware does not support it.
Property: SampClk.Src
Property: SampClk.ActiveEdge
Source Device: cDAQ1Mod1
Source Terminal: PFI3

This was using a single module ethernet carrier (9181).  Do I need to use like a 9185 and wire the clock up to the SMB connector?

[Kevin_Price]

I don't have solid answers and I have limited cDAQ experience, but this question has been lingering a while and I figured I'd offer some educated guesses.  I've not used the 9361 and mainly have a passing awareness of a couple of its unique features -- the ability to do multi-channel counter input measurements and a special frequency measurement method.

I don't really know the signal routing options or restrictions for the 9361, and MAX isn't any help when I set up a simulated device.  It's conceivable (but no guarantees) that you could pair a 9361 with a simpler digital module on a multi-device chassis and still get the job done.

The chassis has 4 internal counters of its own and the digital module would provide access to route signals to and from them.  I expect there should be a way to use an external signal as a sample clock that's shared by chassis counters and 9361 counters to keep them in sync.  I just don't know the exact way to do it.

I would suggest doing some more experimenting to learn what kinds of signal routing are supported for your 9361, especially in a multi-device chassis.  Be sure to try single tasks all by themselves at first, to prevent any resource contention from other tasks.

-Kevin P