Question for NI Motion GOD!

[joeycao]

I have an application where it some times requires moving two axis of motion at the same time.  The motion card is hooked up with a DAQ card through RTSI.  As the two axis are moving simultaneously, I like to have break points that trigger the DAQ card to capture analog inputs.   For example analog inputs 1-5 are for force reading on axis 1 and 6-10 are for force reading on axis 2. 

The PROBLEM I am facing is that the 7340 motion card I have requires me to reset the break point every time it triggers in software, so I think I will have to babysit a complete turn/cycle of an axis before I try to get data off the other axis.  Is there another alternative that allows me to move both axis at the same time and still keep the above mentioned data capturing capability?

My thoughts:

Solution1: One thing I thought of was may be get the 7350 card where I can load the break points onto a buffer on the motion card.  I prefer not to use this solution. 

Solution2: Put algorithm under "No Event" state of my statemachine to constantly check for break point flag from both axis, kind of like an interrupt handler.  I need 180 pts per turn/cycle of each axis, bandwidth might be an issue?

Please post if you need more clarification.

Joey Cao

CLD 

[johnsold]

I am not a motion expert but perhaps reading the analog channels continuously and then sorting the data in software might be a better approach. I am not sure what kinds of signals the motion card sends to create your "break points" but feeding those to unused analog inputs would allow synchornization with the force inputs. I used this method to synchronize some digital stimulus triggers with the analog data responses.

Lynn

[joeycao]

Well continuously reading analog inputs would work if I did not need to know the exact motion position of every DAQ analog inputs value.  I am using RTSI 0 to generate a sample clock for the DAQ card to grab the corresponding inputs in a timely fashion.  I could probably use the motion IO to trigger the DAQ card, but I think that will probably be the same.

[GiGe]

Hi Joey,

Both of your solutions are good ones, but something else you can try is using the Read per Axis.flx.  You can use one of these vi’s to monitor the status of each axis.  If they are placed in parallel loops then you will be able to re-enable the break points after they have been triggered.  Let me know if this helps.

Have a great day,

GG