Turning Reference attenuation off for AOs on 6230 is causing DOs not to work

[Gilla]

I'm using a 6230 board under RTX for AI, AO, and DIO.  I have been able to get the DOs working using the dioex2.cpp example.  However, when I encorporate this DO logic into my code that is reading already reading AIs and DIs, writing AOs, all of the DO channels are changing from either 5V or 0V to 1.9V after the call  board->Static_AI_Control[dac+4].writeRegister(0) in ao.cpp.  Once this condition happens, I have to manually reset the DO channels using the Measurement & Automation Explorer->Reset Device function, then via the Test Panel, set the DOs either high or low.

Is this call to Static_AI_Control[dac+4].writeRegister(0) necessary?  I was suprised to see the "AI" reference in the AO routines.

Thanks,

Mike

[Tom_W_[DE]]

Hi Mike-

Good catch.  The 6230 (and other 623x isolated M Series devices) do not require the call to Static_AI_Control, and making the call as coded in the MHDDK will result in tristating the DO lines (as you observed).  You can remove this call and all should (hopefully) be well.

Hope this helps-

[Tom_W_[DE]]

Hi Mike-

I want to reword and add to my post for clarity, but alas I have passed the edit time limit.  Here's my revised post:

Hi Mike-

Good catch.  The 6230 (and other 623x isolated M Series devices) do not require the call to Static_AI_Control in aoConfigureDAC(), and making the call as coded in the MHDDK will result in tristating the DO lines (as you observed).  You can remove this call and all should (hopefully) be well.

On a related note, you will want to make sure, in addition to removing that line from aoConfigureDAC(), that you write Static_AI_Control[7] with a value of '1'.  This serves as an enable signal for the DO buffer on the I/O connector side of the isolation barrier.

Hope this helps-

Message Edited by Tom W [DE] on 04-25-2008 04:58 PM