abnormal TTL counting while using USER2

[Rhou7]

Hi we have one PCIe-6323 and a BNC-2110 in our setup. In order to count two different TTL pulses, we have to use two port from BNC-2110. 

However, since we only have one PCIe-6323, the only port we can use to count is PFI0. So later we connected user-defined port, or USER2 to PFI8. Finally it looks like:

channel 1: TTL1----->PFI0

channel 2: TTL2----->USER2<--->PFI8

Both PFI0 and PFI8 are used for counting. But they gave out different values for the same signal. The channel 2 always gave us a 10 times larger count than channel 1. We do not know what's going on there.

We tried to connect USER2 to another counter port, say PFI 3 or PFI 5. The same situation happens.  It is about the USER2 port.

Can someone help us fixing that? Thanks.

[Kelly_B]

Hi Rhou7, 

Have you tried using USER1 instead of USER2?  Do you experience the same issue?

How is your counter task set up?  Its possible that it is a setting in NI MAX