Hello,
I have a PXIe-1078 chassis with PXIe-8840 embedded controller (Win 7 OS) and PXIe-4137 SMU. I need to acquire data for a window of time (trivial) while I trigger an external lamp supply (5V pulse trigger to a Xenon Flash Lamp power supply)
I configured the SMU to trigger on Software measure trigger (niDCPower configure software edge measure trigger.vi) and to route the Measure Trigger to the SMB trigger line of the 8840 (niDCPower Export Signal.vi) so I can trigger the flash lamp. This approach was recommended by an NI employee when I was configuring the chassis, so I currently don't have any other modules I could use (digital I/O for example).
While my program is running, the SMB trigger behaves as expected. I get a 250ns, 5V pulse out of the SMB trigger connection.
My problem is that when my VI is not running (say after turning on the chassis or closing the program) I get a DC 5V signal at the SMB connection. This results in my flash lamp triggering as fast as it is able (capacitors take a few seconds to charge) which is a huge safety concern for operators. Is there a way I can have the PXIe-8840 SMB trigger default to 0V instead of 5V or route to one of the PXI back-plane trigger lines?