cannot control ACK line in buffered pattern output mode

[bwz]

I am performing a high-speed, buffered pattern output with a PCI-6534 card  (actually, 2 synched cards, but that seems irrelevant).  I need the ACK line to remain high (5 V) while the buffer is being output.  Instead, the ACK remains low or slips into a tri-state mode where it just follows the load.  I know that I am able to set the ACK line high or low...I have written a test vi to do that.  I simply cannot tell it to remain high during the buffered output.

The buffered output process begins with the DIO config vi, which has in it an option for Acknowledge polarity ("active" or "no").  The digital mode config vi is also contained therein, and it seems to have options to set the Acknowledge mode to "high" or "low."  Changing these option seems to do nothing to the output ACK line during the buffered looping...it still will not hold at 5 V.

How can I tell the ACK line to stay high?



Thank you anyone for your help on this.

Benjamin

[Sean_C.]

Hello Benjamin,

After looking at the NI 653x User Manual, it appears that you cannot control a group's control lines if you are using that group in Pattern I/O or Handshaking modes.  However, if you have one group that is not in Handshaking or Pattern I/O, then you should still be able to set the state of that group's control lines.  Please see pages 2-3 through 2-6 in the User Manual for more information.

http://www.ni.com/pdf/manuals/371464d.pdf

I hope this helps.  Please let me know if you have any further questions.

Regards,
Sean C.