Is there a maximum delay in ms that can be set into "Sequence" or other Pre and Post execution delays.

[jeff85207]

Problem Description :
I've set up a simple procedure to drive ports on DIO card, NI-USB-6501, which in turn drives relays using
DAQmx generate, Sequence steps and a Conditional loop.  Program runs fine when
tried with 10 minute Sequence pre-execution delay, (600,000ms set into pre-execution delay).  
Tried running with longer delay of 1 hour, (3600000ms) and the procedure won't continue to
the next step, it seems to be treating the Sequence pre-execution delay as infinate.  My final goal is a Conditional loop to run 3 times which simply enables 2 DIO channels high for 5 hours, and then the same channels low for 93 hours 20 minutes.  Is there a maximum time is milliseconds that can be set into the Sequence?  Do I need to add sequence steps to achieve the amount of delay I need?  Prior to the Conditional repeat there is also a DIO Digital generation step to set all DIO ports low as a reset, and then one DIO port high as a fail safe to turn on my relay card, then another generation after the Conditional loop to again set all the DIO ports low.  The project is run Once.  Again it operates just fine when I've used 10 minutes in the Sequence step as a delay, but not when tested it at 1
hour in the delay. 

[Case_in_Point]

Hi Jeff,

Have you tried any values in between 10 minutes and 1 hour? Something like 30 minutes, just to see if you can find where the behavior changes? I'm not aware of any limits, but seeing as it is measured in ms, asking for an hour could certainly be beyond what that delay is intended for. Multiple steps could be an option; give that a shot.

Cason

Applications Engr., NI

[jeff85207]

I'm in the process of trying to whittle it down.  1Meg ms works but 2Meg ms does not.  Trying 1.5Meg ms and if that doesn't work I'll probably start to try stacking 1Megs.

[jeff85207]

I did not find the actual upper limit in milliseconds that can be utilized, it is somewhere between 1Million and 1.5M.  Instead due to the simplicity of this project I strung together conditional loops to control the DIO channels, each loop with a sequence set for 10 minutes of delay (600,000ms), and conditioned each loop to exit with the multiple of 10 minutes needed to reach my lengthy delay times and used display meters for each loop to show the loops progress.

 As a side note, this project was to control relays which in turn control multiple audio amplifiers within environmental chambers under temp / humidity / altitude variations for very lengthy time frames required by automotive manufacturers.  A second project running simultaniously is then recording amplifier characteristics like current, output, distortion etc.