T7-Pro Frequency In issue | LabJack
 

T7-Pro Frequency In issue

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Walid Ayoub
it2's picture
T7-Pro Frequency In issue

Hello LabJack support, 

The Frequency In (Extended Feature Index 3, Rising Edges) seems to miss the very first positive edge anytime after the DIO#_EF_ENABLE is switched from 0 to 1, however, this is not the case for Falling Edges (Extended Feature Index 4), the falling edges works as I believe it was intended.

I have only tested this using DIO0. Kipling and a Custom C# code I wrote reproduces the same error.

 

EDIT: This is consistent behaviour for both One-shot and Continous mode.

 

 

LabJack Support
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I see the same thing. A

I see the same thing. A firmware investigation has been started.

LabJack Support
LabJack Support's picture
I have been testing various

I have been testing various conditions and hardware settings. So far, I have found...

The first rising edge is captured properly only when the line is high when the DIO_EF is configured and the signal idles high. I have tried several hardware configuration options with no good results. At the moment this seems like a hardware nuance.

 

While we look at this, I recommend trying L2L.

Walid Ayoub
it2's picture
I switched to use Negative

I switched to use Negative Edges for now so this is not causing any major problem for me at the moment. but please keep me updated if this ever gets fixed.

One interesting experiment is to check if you miss a negative edge while the Input idles high first. (exactly the opposite) 

LabJack Support
LabJack Support's picture
We have been unable to get

We have been unable to get the hardware to capture that first edge. A note has been added to the Frequency In section of the datasheet.