NI PXI-6551: tristate output lines during a dynamic generation

[PEng]

I am using a PXI-6551 for dynamic pattern generation and acquisition and I need to set some of the output lines to a high impedance state (tri-state) during a dynamic generation session without stop or pause the pattern generation session (other output lines must continue generate pattern so I cannot define an idle state and pause the session). Is it possible with the 6551?

Fabio

[AlessioD]

Fabio,

if you take a look at the Online Help for the niHSDIO Tristate Channels Function in the NI-HSDIO library, you can read that calling this function allows you to immediately set the specified lines in a high-impedance state without having to stop the session that is running on the 6551 device.
Wiring in a TRUE constant Tristates the lines and wiring in a FALSE constant sets the lines back to normal impedance.
Try and see what happens using this function.
Regards,

AlessioD
National Instruments

[PEng]

AllessioD,
thank you for your answer. You are right: calling the NIHSDIO Trisate Channels I can set specified lines to a high-impedance state. But during the dynamic generation session I have to put some lines in a high-impedance state at specified time interval and back to a normal impedance state. This transition to a high-impedance state must be synchronous with 0-1 transition of other lines of the pattern with severe timing constraints and I don't think that I can achieve this with the NIHSDIO Tristate Channels function. Is it possible in another way?

Regards
Fabio Magnino