How can I set a on/off timer(ex. Turn on at 7am, and turn off at 8pm)?

[Detroit]

I want to set up a timer that turns of a mass flow controller at 7 am and turn it off at 8 pm everyday? Any suggestions (just for the timer part)?

[GerdW]

Hi Detroit,

check the system time, get the hours component, check range

(using a 24h time format is clearly easier here)

Use the usual boolean logic to detect changes in the state of "daytime?" (shift registerto remember old states; NOT(old state) AND (new state) to detect rising edge...)

Message Edited by GerdW on 08-17-2008 06:39 PM

[Pie56694]

Hi Detroit,

Depending on how critical the system is, you may want to consider a real-time platform.  If the reliability of the Windows Operating System is acceptable, there is a nifty scheduler built into Windows XP.  To launch the scheduler, goto Start » Settings » Control Panel » Scheduled Tasks » Add Scheduled Task.  You can browse to any EXE file.  If your VI-built-EXE runs for an hour, Windows can take care of scheduling the start.  Just another approach from GerdW's, no better or worse as far as I can tell.