positional count with 6036E and BNC-2110

[CFleischer]

Hello!

I've a problem with a quad-encoder connected to the bnc-2110 connector box. The box is connected to an 6036E card.
When I wire channel A of the quad encoder to the source pin (PFI8), GATE (PFI9) to +5V and UP/DOWN (DIO6) to +5V everything works as expected: No matter in which direction the encoder counts, values are reported as expected. But when I connect the channel B (90 deg phase shift) to the UP/DOWN-pin (DIO6), the negative values are twice as large as expected (the positive values are fine). What's wrong here?
Are the additional edges of the UP/DOWN-pin counted?
Is it okay to wire the encoder directly or do I need some small circuit in between?
Is this a special "mode" of the 6036? Configuration error?
Addit
ionally wiring the GATE-pin to the channel B does not help: the counter just counts in one direction afterwards (but those values are ok in both directions, just the sign is wrong!).
Is it a problem that some of the pins might be used as output-pins also? (this is not the case here, but maybe this is why it goes wrong).

I appreciate ANY help!
Thanks,
Christian

[Robert H.]

Hello Christian,

in principle you don't need an additional circuit between your card and the encoder.
did you try to watch the signal of your encoder with a scope?
what happens, if you switch A and B signals?
did you connect the ground from your encoder to the ground of the card, to make sure to have the same ground level?

regards,
Robert H
National Instruments