Quentin

Ok great. Do you have an explaination for the issue of the process variable not showing up in the PID event graph/ figure?

see Posted Wednesday at 11:15 PM

New issue, the if loop control the relay will only run once per for loop. 

i.e. it will iterate through the for loop run the if loop once and then wait for the delay to be completed.

for (private i = 0, i < numrows(tempSPs), i++)
   curSP = tempSPs[i]
   if(Out < 0)
      Relay_control[0] = 0
      delay(0.02)
   else
      Relay_control[0] = 1
      delay(0.02)
   endif
   delay(tempDuration[i])
   ?tempSPs[i]
   ?tempDuration[i]
endfor

What is required is for the if loop to actually run continuously during the whole delay of the for loop, would this work?

for (private i = 0, i < numrows(tempSPs), i++)
   curSP = tempSPs[i]
   private startTime = systime()
   private elapsedTime = 0
   while (elapsedTime < tempDuration[i])
      if(Out < 0)
         Relay_control[0] = 0
         delay(0.02)
      else
         Relay_control[0] = 1
         delay(0.02)
      endif
      elapsedTime = systime() - startTime
   endwhile
   delay(tempDuration[i])
   ?tempSPs[i]
   ?tempDuration[i]
endfor

Found issue, my process variable dissapeared for no reason on PID1 but is present on PID2...

Test2_debug.ctl

I would also like to have a live time gage to indicate the live delay, would that be possible to display on my page0?

Great!

Like this then? Or do i need to setup globals first?

while(1)
   for (private i = 0, i < numrows(tempSPs), i++)
      curSP = tempSPs[i]
         if(Out < 0)
            Relay_control[0] = 0
            delay(0.02)
         else
            Relay_control[0] = 1
            delay(0.02)
         endif
      delay(SPduration[i])
   endfor
endwhile

Could i set an series maybe using a button- "set to" action and then have my sequence loop iterate through each value for the delay in time1:

Ok so I changed it a little bit to make it simple. We determined we actually don't need the PWM at all.

Now how do you suggest i setup multiple setpoints/ durations?

Test2_debug.ctl

Ok it's all good! I got it fixed with the labjack support. 

Setup solution:

Relay + port connect to VS on LJ

Relay - port connect to GND

Relay D port connect to FIO0 

Then setup your channel like this:

Rout = 1 (relay open)

Rout = 0 (relay closed)

My relay needs to operate at 3V does the labjack automatically adapt to 3v or I need to plug my relay on DAC0 and set the output (D to A) to 3v?

Maybe it is because my labjack is not configured on DAQfactory? When I click on configure device it only has the LabJack UD option that would correspond to U6 but then it promts me for a U9 ethernet. So I have configured any device...

ok the layout is good, i confirm it is an issue with DAQ factory. it seems like the signal doesn't stay high by using the toggle between feature... since it only goes to zero for a second and then back to 1. If i click continuously it stays at zero

ok understood. Still doesn't work after rebooting.

Troubleshooting my setup right now

this is weird, how come the sequence had anything to do with it, especially when they were not running?? And how come now it could be a reboot, does it lack robustness? I though this was industrial grade software.

alright then it might be an issue with my relay/ labjack pulg ins.

Currently have NC/NO/COM relay with NC on FIO0 and COM on GND

No, I have even deleted them now end I still have the same issue. I tried making a sequence that would keep it on or off depending on the status but it overrides the button action...

Test2_debug.ctl

Yes sorry, this has nothing to do with the issue, I had just changed all the names so it would not be confusing for you.

Here is a cleaner document. I still have the same issue. It switches the relay off for 1 second and then it's on again...

Test2.ctl

No I confirm that I need to implement a PID loop/ PWM in order to control more precisely the temperature of my casting ptocess

More precisely, how can I use the PID built-in feature with multiple temperature setpoints? A simple ramp and soak as presented above is not satisfactory for my application...

Great, thank you!

Two follow up questions:

1/     Where do I write this script? Sequence (which thread priority... PID?) or PID loop/ event tab?

global tempHyst = 1
while(1)
   if (TC[0] > curSP)
      relay_control = 0
   endif
   if (TC[0] < curSP - tempHyst)
      relay_control = 1
   endif
   delay(1)
endwhile

2/     Where can I read in the temperature setpoints from the page0 button/ set to as you suggested? How can IU communicate with the blue box/ "set point" input or do I have to add these directly from a sequence loop? If so can the button create a variable or I would have to create a distinct channel to store all of these values like in the exemple below? 

global tempSPs = {Temp1[0],Temp2[0],Temp3[0],Temp4[0],Temp5[0]}
global tempDuration = {time1[0],time2[0],time3[0],time4[0],time5[0]}

Thank you for the clairifications. Sorry I am very new to this...

I confirm that I am using an SSR relay. 

Would it be possible to read in those setpoints and durations from the page0? And then how could I communicate with my relay to ask it to stop/restart when it has reach the setpoint in question. 

Would I write the script in the sequence or in the PID loop - event script? 

Example:

Trying to reach 115 degrees and stay there for 2min, then 125 degrees and stay there for 3 min, then 135 degrees and stay there for 4min, then back to 120 and stay there for 5min and back to 110degrees and stay there for 5min with the minimum amount of overshoot.

I have attached my .ctl

Test2.ctl

Here is my setup, it's a bit messy because I'm also struggling to make a PID loop to control the Relay with 3 temperature setpoints from user inputs with their respective duration. 

Test2.ctl

I have a relay connected to my digital I/O (FIO0) on my labjack, I have created a channel (Dig Out) called relay_control to switch on/off this relay with a daqfactory page0 - descriptive text component (expression: relay_control[0], action: toggle between). for some reason when i click on the page component it does send a signal but then the relay switches back off because the signal is not sustained... I though that was the whole point of a "toggle". Do you know how I can fix this? 

I am trying to setup a PID loop with 5 different temperatures setpoints and 5 distinct durations for each setpoint. How do you suggest I proceed? 

The goal is to basically have a 5 setpoint entries on the page0 and 5 duration entries. The PID is controlling a relay that truns On/Off a heat pad. I am reading the temperature from a K-type thermocouple. 

I am using a labjack U6