how to untrigger 6008 in signal express

[Dave Sb]

Hi all,

we wish to collect 4 channels of analog signal throughout the day.  We only want data collected for 32 seconds at 1024 second intervals.  To do this we built an external circuit (externally timed by a 1 Hz clock signal) that is capable of producing a high logic level during the 30 second period.  We have Signal Express and are running a 6008 data acquisition card (Please note this card does not have hardware timing, but only software timing).  So I added a step to read 4 channels of analog.  I configured it to start on the rising edge of the trigger.  All fine so far.  here are my questions:

1. When I run the program it sees the trigger and starts but if I drop the logic low it keeps going.  How do I get it to stop collection?

2. how do I get the program to continue running and repeat at the next trigger?

Ideally, we would like to set this up and let it run weekly between data offloads.

3. can I put a weeks worth of data into a single log file?

Any suggestions would be much appreciated! 

[Jordan F]

Hi Dave,

To clarify, the USB-6008 is software timed for its digital I/O and analog ouput but you do have an internal clock for analog input (up to 10kS/s).  Also, you can not perform retriggerable analog input with this device or use an external sample clock.  So, for your application, the best way to perform what you are doing is to set up the acquisition in Signal Express and try using the recording options available.  In the recording options you can have start and stop conditions to acquire for a specified amount of time.  I attached a couple of screenshots to show what I mean.   

Logging Continuous Data to Multiple Files in LabVIEW SignalExpress

http://digital.ni.com/public.nsf/allkb/393BA6B1F74DA8AB862572910008661D?OpenDocument

Message Edited by Jordan F on 05-19-2009 11:40 AM