How To Get Daqfactory To Resume A Valve In The Event Of Power Outage?

[meerooo80]

I'm trying to control a valve automatically, off for 30 minutes each day at 11pm.  I also need to make sure the sequence stays running if the power goes off to the valve.  How do I do this?

[AzeoTech]

Here's the code:

 

//valve position "3000" is the open position, PILS sample

//valve position "0" is the closed position, background sample

device.Three_way_valve.Write("100r" + chr(13))

device.Three_way_valve.Write("3000g" + chr(13))

//valve position opened for 23.5 hrs/day

//valve position closed for 30min/day

 

private nexttime = 23h00
if (systime() > nexttime)
   nexttime += 86400
endif
// open valve
private offTime = 1800 // 30 min /day off time
private loopTime = 86400 // once a day
device.Three_way_valve.Write("3000g" + chr(13))
private mode = 1  // 1 = open, 0 = closed
device.Three_way_valve.Purge()
while(1)
   try
      if (systime() > nexttime)
         if (mode == 1)
            try
               // close the valve
               device.Three_way_valve.Purge()
               device.Three_way_valve.Write("0g" + chr(13))
               device.Three_way_valve.Read(4)
               mode = 0
               nexttime += offTime
            catch()
               ? strLastError
            endcatch
         else
            try
               // open the valve
               device.Three_way_valve.Purge()
               device.Three_way_valve.Write("3000g" + chr(13))
               device.Three_way_valve.Read(4)
               mode = 1
               nexttime += loopTime - offTime
            catch()
               ? strLastError
            endcatch
         endif
      endif
   catch()
      ? strLastError
   endcatch
   delay(1)
endwhile

I use the nexttime variable to control when the next time an event should occur (open or closing of the valve), and the mode variable to keep track of whether I need to open or close the valve.  The internal try/catch blocks ensure that things happen even if the power goes off.  Note that if the power is off when an event occurs and stays off until the next event time (i.e. power is off from 10:59pm to 11:31pm), the sequence will do both events in rapid (1 second) succession once the power is restored.

[meerooo80]

Here is the code I am using for testing the valve.

 

 

private nexttime = 02h15   // first time to switch

if (systime() > nexttime)

   nexttime += 10

endif

// open valve

private offTime = 20 // how long valve is off for,  30 min /day off time

private loopTime = 30   // total loop time (off + on time).  On time = looptime - offtime.  86400 = one day

device.Three_way_valve.Write("3000g" + chr(13))

private mode = 1  // 1 = open, 0 = closed

device.Three_way_valve.Purge()

while(1)

   try

      if (systime() > nexttime)

         if (mode == 1)

            try

               // close the valve

               device.Three_way_valve.Purge()

               device.Three_way_valve.Write("0g" + chr(13))

               device.Three_way_valve.Read(4)

               mode = 0

               nexttime += offTime

            catch()

               ? strLastError

            endcatch

         else

            try

               // open the valve

               device.Three_way_valve.Purge()

               device.Three_way_valve.Write("3000g" + chr(13))

               device.Three_way_valve.Read(4)

               mode = 1

               nexttime += loopTime - offTime

            catch()

               ? strLastError

            endcatch

         endif

      endif

   catch()

      ? strLastError

   endcatch

   logging.Three_way_valve_log.strFileName = "c:\DAQFactoryData\Three_way_valve_" + formatDateTime("%m.%d.%y", systime ()) + ".csv"

   position1=mode

   delay(1)

endwhile

[AzeoTech]

That's because you have the first time set to 2h15 which is 2:15am.  Judging from the time of your post, I'm guessing you really want 14h15.

[meerooo80]

well I have checked it using military time and it is not working either.

[AzeoTech]

Look in the comm monitor and see if the command are going out the serial port and if the device is responding.  Also look for alerts.

[meerooo80]

The valve is responding when I give it commands on the comm monitor, yet not with the code at hand. 

 

No alerts.

[AzeoTech]

Do the commands appear at all in the comm monitor when the sequence is running?

 

nexttime += 10 really should stay as nexttime += 86400.  The way you have it, if its any time after 2:15am when you start the sequence you are basically going to have the valve switch back and forth every second until it catches up.