How do I prevent false triggering?

[BradB3030]

I have a VB6 Application that reads 8 channels of voltages from 0 to 10 volts. However, the trigger behavior is very erratic. I am using the PFI0 pin on the PCI-6033E DAQ, and even when set to HWAnalog trigger, it will trigger at any voltage.

I took the entire system apart and touched a wire to the PFI0 pin, and it triggered. The wire was not connected to anything. I'm wondering what the best solution is for my design.

The system's application is on a molding press. When the mold closes, it needs to trigger. It is usually every 15 seconds, but sometimes there will be a long pause between cycles and before the mold closes again.

Any help would be appreciated.

[RIO-Todd]

Brad,

Are you working with an example program or a program that you've created? I would suggest to start with an example program. There is an example program installed with NI-DAQ for visual basic entitled 'DAQsingleBufAnalogTrig' and can be found in the ...\Program Files\National Instruments\NI-DAQ\Examples\VBasic\Ai directory. I open and run this example with an E Series card and the trigger level functions correctly.

One thing you might want to take a look at is the help for the Configure_HW_Analog_Trigger function. The high and low levels you give this function are not actual voltage levels. With a 16-bit device, the the low and high values will be between 0 and 4096. The values 0 through 4096 will correlate with voltage values based on whether you're
triggering off of an analog channel or PFI line and whether your device is configured for unipolar or bipolar.

I've linked the NI-DAQ reference where you can view this information. I hope this helps.

NI-DAQ Function Reference Manual for PC Compatibles
http://digital.ni.com/manuals.nsf/webAdvsearch/1630A0B68738B269862567C1007A2912?OpenDocument&vid=niwc&node=132100_US

Regards,

Todd D.